el refactor

Cargo.toml

@@ -1,30 +1,44 @@
-[package]
-name = "ethers"
-version = "0.1.0"
-authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
-edition = "2018"
+[workspace]
 
-[dependencies]
-ethereum-types = { version = "0.9.2", default-features = false, features = ["serialize"] }
-url = { version = "2.1.1", default-features = false }
-async-trait = { version = "0.1.31", default-features = false }
-reqwest = { version = "0.10.4", default-features = false, features = ["json", "rustls-tls"] }
-serde = { version = "1.0.110", default-features = false, features = ["derive"] }
-serde_json = { version = "1.0.53", default-features = false }
-thiserror = { version = "1.0.19", default-features = false }
-rustc-hex = { version = "2.1.0", default-features = false }
-rand = { version = "0.5.1", default-features = false } # this should be the same rand crate version as the one in secp
-secp256k1 = { version = "0.17.2", default-features = false, features = ["std", "recovery", "rand"] }
-zeroize = { version = "1.1.0", default-features = false }
-tiny-keccak = { version = "2.0.2", default-features = false }
+members = [
+    # "./crates/ethers",
+    # "./crates/ethers-abi",
+    # "./crates/ethers-contract",
+    # "./crates/ethers-derive",
+    # "./crates/ethers-providers",
+    # "./crates/ethers-signers",
+    "./crates/ethers-types",
+    # "./crates/ethers-utils",
+]
 
-solc = { git = "https://github.com/paritytech/rust_solc "}
-rlp = "0.4.5"
-ethabi = "12.0.0"
-bincode = "1.2.1"
-arrayvec = "0.5.1"
-
-[dev-dependencies]
-tokio = { version = "0.2.21", features = ["macros"] }
-failure = "0.1.8"
-rand = { version = "0.5.1" }
+# [dependencies]
+# ethers-derive = { path = "ethers-derive", optional = true }
+# 
+# ethereum-types = { version = "0.9.2", default-features = false, features = ["serialize"] }
+# url = { version = "2.1.1", default-features = false }
+# async-trait = { version = "0.1.31", default-features = false }
+# reqwest = { version = "0.10.4", default-features = false, features = ["json", "rustls-tls"] }
+# serde = { version = "1.0.110", default-features = false, features = ["derive"] }
+# serde_json = { version = "1.0.53", default-features = false }
+# thiserror = { version = "1.0.19", default-features = false }
+# rustc-hex = { version = "2.1.0", default-features = false }
+# rand = { version = "0.5.1", default-features = false } # this should be the same rand crate version as the one in secp
+# secp256k1 = { version = "0.17.2", default-features = false, features = ["std", "recovery", "rand"] }
+# zeroize = { version = "1.1.0", default-features = false }
+# tiny-keccak = { version = "2.0.2", default-features = false }
+# 
+# solc = { git = "https://github.com/paritytech/rust_solc", optional = true }
+# rlp = "0.4.5"
+# ethabi = "12.0.0"
+# bincode = "1.2.1"
+# arrayvec = "0.5.1"
+# 
+# [dev-dependencies]
+# tokio = { version = "0.2.21", features = ["macros"] }
+# failure = "0.1.8"
+# rand = { version = "0.5.1" }
+# 
+# [features]
+# default = ["derive"]
+# derive = ["ethers-derive"]
+# 

contract.sol

@@ -0,0 +1,22 @@
+pragma solidity ^0.6.6;
+
+contract SimpleStorage {
+
+    event ValueChanged(address indexed author, string oldValue, string newValue);
+
+    string _value;
+
+    constructor(string memory value) public {
+        emit ValueChanged(msg.sender, _value, value);
+        _value = value;
+    }
+
+    function getValue() view public returns (string memory) {
+        return _value;
+    }
+
+    function setValue(string memory value) public {
+        emit ValueChanged(msg.sender, _value, value);
+        _value = value;
+    }
+}

crates/ethers-abi/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ethers-abi"
+version = "0.1.0"
+authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

crates/ethers-contract/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ethers-contract"
+version = "0.1.0"
+authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

crates/ethers-contract/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}

crates/ethers-derive/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "ethers-derive"
+version = "0.1.0"
+authors = ["Nicholas Rodrigues Lordello <nlordell@gmail.com>", "Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+license = "MIT OR Apache-2.0"
+repository = "https://github.com/gnosis/ethcontract-rs"
+homepage = "https://github.com/gnosis/ethcontract-rs"
+documentation = "https://docs.rs/ethcontract"
+description = "Code generation for type-safe bindings to Ethereum smart contracts"
+
+[dependencies]
+ethers-abi = { path = "../ethers-abi" }
+
+anyhow = "1.0"
+curl = "0.4"
+Inflector = "0.11"
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = "1.0.12"
+url = "2.1"

crates/ethers-derive/src/README.md

@@ -0,0 +1,55 @@
+# `ethcontract-generate`
+
+An alternative API for generating type-safe contract bindings from `build.rs`
+scripts. Using this method instead of the procedural macro has a couple
+advantages:
+- Proper integration with with RLS and Racer for autocomplete support
+- Ability to inspect the generated code
+
+The downside of using the generator API is the requirement of having a build
+script instead of a macro invocation.
+
+## Getting Started
+
+Using crate requires two dependencies - one for the runtime and one for the
+generator:
+
+```toml
+[dependencies]
+ethcontract = { version = "...", default-features = false }
+
+[build-dependencies]
+ethcontract-generate = "..."
+```
+
+It is recommended that both versions be kept in sync or else unexpected
+behaviour may occur.
+
+Then, in your `build.rs` include the following code:
+
+```rs
+use ethcontract_generate::Builder;
+use std::env;
+use std::path::Path;
+
+fn main() {
+    let dest = env::var("OUT_DIR").unwrap();
+    Builder::new("path/to/truffle/build/contract/Contract.json")
+        .generate()
+        .unwrap()
+        .write_to_file(Path::new(&dest).join("rust_coin.rs"))
+        .unwrap();
+}
+```
+
+## Relation to `ethcontract-derive`
+
+`ethcontract-derive` uses `ethcontract-generate` under the hood so their
+generated bindings should be identical, they just provide different APIs to the
+same functionality.
+
+The long term goal of this project is to maintain `ethcontract-derive`. For now
+there is no extra work in having it split into two separate crates. That being
+said if RLS support improves for procedural macro generated code, it is possible
+that this crate be deprecated in favour of `ethcontract-derive` as long as there
+is no good argument to keep it around.

crates/ethers-derive/src/lib.rs

@@ -0,0 +1,503 @@
+//! Implementation of procedural macro for generating type-safe bindings to an
+//! ethereum smart contract.
+#![deny(missing_docs, unsafe_code)]
+
+extern crate proc_macro;
+
+mod spanned;
+use crate::spanned::{ParseInner, Spanned, parse_address, Address, Builder};
+
+use ethers::abi::{Function, Param, ParamType, FunctionExt, ParamTypeExt};
+
+use proc_macro::TokenStream;
+use proc_macro2::{Span, TokenStream as TokenStream2};
+use quote::{quote, ToTokens as _};
+use std::collections::HashSet;
+use std::error::Error;
+use syn::ext::IdentExt;
+use syn::parse::{Error as ParseError, Parse, ParseStream, Result as ParseResult};
+use syn::{
+    braced, parenthesized, parse_macro_input, Error as SynError, Ident, LitInt, LitStr, Path,
+    Token, Visibility,
+};
+
+// TODO: Make it accept an inline ABI array
+/// Proc macro to generate type-safe bindings to a contract. This macro accepts
+/// an Ethereum contract ABIABI or a path. Note that this path is rooted in
+/// the crate's root `CARGO_MANIFEST_DIR`.
+///
+/// ```ignore
+/// ethcontract::contract!("build/contracts/MyContract.json");
+/// ```
+///
+/// Alternatively, other sources may be used, for full details consult the
+/// `ethcontract-generate::source` documentation. Some basic examples:
+///
+/// ```ignore
+/// // HTTP(S) source
+/// ethcontract::contract!("https://my.domain.local/path/to/contract.json")
+/// // Etherscan.io
+/// ethcontract::contract!("etherscan:0x0001020304050607080910111213141516171819");
+/// ethcontract::contract!("https://etherscan.io/address/0x0001020304050607080910111213141516171819");
+/// // npmjs
+/// ethcontract::contract!("npm:@org/package@1.0.0/path/to/contract.json")
+/// ```
+///
+/// Note that Etherscan rate-limits requests to their API, to avoid this an
+/// `ETHERSCAN_API_KEY` environment variable can be set. If it is, it will use
+/// that API key when retrieving the contract ABI.
+///
+/// Currently the proc macro accepts additional parameters to configure some
+/// aspects of the code generation. Specifically it accepts:
+/// - `crate`: The name of the `ethcontract` crate. This is useful if the crate
+///   was renamed in the `Cargo.toml` for whatever reason.
+/// - `contract`: Override the contract name that is used for the generated
+///   type. This is required when using sources that do not provide the contract
+///   name in the artifact JSON such as Etherscan.
+/// - `mod`: The name of the contract module to place generated code in. Note
+///   that the root contract type gets re-exported in the context where the
+///   macro was invoked. This defaults to the contract name converted into snake
+///   case.
+/// - `methods`: A list of mappings from method signatures to method names
+///   allowing methods names to be explicitely set for contract methods. This
+///   also provides a workaround for generating code for contracts with multiple
+///   methods with the same name.
+/// - `event_derives`: A list of additional derives that should be added to
+///   contract event structs and enums.
+///
+/// Additionally, the ABI source can be preceeded by a visibility modifier such
+/// as `pub` or `pub(crate)`. This visibility modifier is applied to both the
+/// generated module and contract re-export. If no visibility modifier is
+/// provided, then none is used for the generated code as well, making the
+/// module and contract private to the scope where the macro was invoked.
+///
+/// ```ignore
+/// ethcontract::contract!(
+///     pub(crate) "build/contracts/MyContract.json",
+///     crate = ethcontract_rename,
+///     mod = my_contract_instance,
+///     contract = MyContractInstance,
+///     deployments {
+///         4 => "0x000102030405060708090a0b0c0d0e0f10111213",
+///         5777 => "0x0123456789012345678901234567890123456789",
+///     },
+///     methods {
+///         myMethod(uint256,bool) as my_renamed_method;
+///     },
+///     event_derives (serde::Deserialize, serde::Serialize),
+/// );
+/// ```
+///
+/// See [`ethcontract`](ethcontract) module level documentation for additional
+/// information.
+#[proc_macro]
+pub fn contract(input: TokenStream) -> TokenStream {
+    let args = parse_macro_input!(input as Spanned<ContractArgs>);
+
+    let span = args.span();
+    expand(args.into_inner())
+        .unwrap_or_else(|e| SynError::new(span, format!("{:?}", e)).to_compile_error())
+        .into()
+}
+
+fn expand(args: ContractArgs) -> Result<TokenStream2, Box<dyn Error>> {
+    Ok(args.into_builder()?.generate()?.into_tokens())
+}
+
+/// Contract procedural macro arguments.
+#[cfg_attr(test, derive(Debug, Eq, PartialEq))]
+struct ContractArgs {
+    visibility: Option<String>,
+    artifact_path: String,
+    parameters: Vec<Parameter>,
+}
+
+impl ContractArgs {
+    fn into_builder(self) -> Result<Builder, Box<dyn Error>> {
+        let mut builder = Builder::from_source_url(&self.artifact_path)?
+            .with_visibility_modifier(self.visibility);
+
+        for parameter in self.parameters.into_iter() {
+            builder = match parameter {
+                Parameter::Mod(name) => builder.with_contract_mod_override(Some(name)),
+                Parameter::Contract(name) => builder.with_contract_name_override(Some(name)),
+                Parameter::Crate(name) => builder.with_runtime_crate_name(name),
+                Parameter::Deployments(deployments) => {
+                    deployments.into_iter().fold(builder, |builder, d| {
+                        builder.add_deployment(d.network_id, d.address)
+                    })
+                }
+                Parameter::Methods(methods) => methods.into_iter().fold(builder, |builder, m| {
+                    builder.add_method_alias(m.signature, m.alias)
+                }),
+                Parameter::EventDerives(derives) => derives
+                    .into_iter()
+                    .fold(builder, |builder, derive| builder.add_event_derive(derive)),
+            };
+        }
+
+        Ok(builder)
+    }
+}
+
+impl ParseInner for ContractArgs {
+    fn spanned_parse(input: ParseStream) -> ParseResult<(Span, Self)> {
+        let visibility = match input.parse::<Visibility>()? {
+            Visibility::Inherited => None,
+            token => Some(quote!(#token).to_string()),
+        };
+
+        // TODO(nlordell): Due to limitation with the proc-macro Span API, we
+        //   can't currently get a path the the file where we were called from;
+        //   therefore, the path will always be rooted on the cargo manifest
+        //   directory. Eventually we can use the `Span::source_file` API to
+        //   have a better experience.
+        let (span, artifact_path) = {
+            let literal = input.parse::<LitStr>()?;
+            (literal.span(), literal.value())
+        };
+
+        if !input.is_empty() {
+            input.parse::<Token![,]>()?;
+        }
+        let parameters = input
+            .parse_terminated::<_, Token![,]>(Parameter::parse)?
+            .into_iter()
+            .collect();
+
+        Ok((
+            span,
+            ContractArgs {
+                visibility,
+                artifact_path,
+                parameters,
+            },
+        ))
+    }
+}
+
+/// A single procedural macro parameter.
+#[cfg_attr(test, derive(Debug, Eq, PartialEq))]
+enum Parameter {
+    Mod(String),
+    Contract(String),
+    Crate(String),
+    Deployments(Vec<Deployment>),
+    Methods(Vec<Method>),
+    EventDerives(Vec<String>),
+}
+
+impl Parse for Parameter {
+    fn parse(input: ParseStream) -> ParseResult<Self> {
+        let name = input.call(Ident::parse_any)?;
+        let param = match name.to_string().as_str() {
+            "crate" => {
+                input.parse::<Token![=]>()?;
+                let name = input.call(Ident::parse_any)?.to_string();
+                Parameter::Crate(name)
+            }
+            "mod" => {
+                input.parse::<Token![=]>()?;
+                let name = input.parse::<Ident>()?.to_string();
+                Parameter::Mod(name)
+            }
+            "contract" => {
+                input.parse::<Token![=]>()?;
+                let name = input.parse::<Ident>()?.to_string();
+                Parameter::Contract(name)
+            }
+            "deployments" => {
+                let content;
+                braced!(content in input);
+                let deployments = {
+                    let parsed =
+                        content.parse_terminated::<_, Token![,]>(Spanned::<Deployment>::parse)?;
+
+                    let mut deployments = Vec::with_capacity(parsed.len());
+                    let mut networks = HashSet::new();
+                    for deployment in parsed {
+                        if !networks.insert(deployment.network_id) {
+                            return Err(ParseError::new(
+                                deployment.span(),
+                                "duplicate network ID in `ethcontract::contract!` macro invocation",
+                            ));
+                        }
+                        deployments.push(deployment.into_inner())
+                    }
+
+                    deployments
+                };
+
+                Parameter::Deployments(deployments)
+            }
+            "methods" => {
+                let content;
+                braced!(content in input);
+                let methods = {
+                    let parsed =
+                        content.parse_terminated::<_, Token![;]>(Spanned::<Method>::parse)?;
+
+                    let mut methods = Vec::with_capacity(parsed.len());
+                    let mut signatures = HashSet::new();
+                    let mut aliases = HashSet::new();
+                    for method in parsed {
+                        if !signatures.insert(method.signature.clone()) {
+                            return Err(ParseError::new(
+                                method.span(),
+                                "duplicate method signature in `ethcontract::contract!` macro invocation",
+                            ));
+                        }
+                        if !aliases.insert(method.alias.clone()) {
+                            return Err(ParseError::new(
+                                method.span(),
+                                "duplicate method alias in `ethcontract::contract!` macro invocation",
+                            ));
+                        }
+                        methods.push(method.into_inner())
+                    }
+
+                    methods
+                };
+
+                Parameter::Methods(methods)
+            }
+            "event_derives" => {
+                let content;
+                parenthesized!(content in input);
+                let derives = content
+                    .parse_terminated::<_, Token![,]>(Path::parse)?
+                    .into_iter()
+                    .map(|path| path.to_token_stream().to_string())
+                    .collect();
+                Parameter::EventDerives(derives)
+            }
+            _ => {
+                return Err(ParseError::new(
+                    name.span(),
+                    format!("unexpected named parameter `{}`", name),
+                ))
+            }
+        };
+
+        Ok(param)
+    }
+}
+
+/// A manually specified dependency.
+#[cfg_attr(test, derive(Debug, Eq, PartialEq))]
+struct Deployment {
+    network_id: u32,
+    address: Address,
+}
+
+impl Parse for Deployment {
+    fn parse(input: ParseStream) -> ParseResult<Self> {
+        let network_id = input.parse::<LitInt>()?.base10_parse()?;
+        input.parse::<Token![=>]>()?;
+        let address = {
+            let literal = input.parse::<LitStr>()?;
+            parse_address(&literal.value()).map_err(|err| ParseError::new(literal.span(), err))?
+        };
+
+        Ok(Deployment {
+            network_id,
+            address,
+        })
+    }
+}
+
+/// An explicitely named contract method.
+#[cfg_attr(test, derive(Debug, Eq, PartialEq))]
+struct Method {
+    signature: String,
+    alias: String,
+}
+
+impl Parse for Method {
+    fn parse(input: ParseStream) -> ParseResult<Self> {
+        let function = {
+            let name = input.parse::<Ident>()?.to_string();
+
+            let content;
+            parenthesized!(content in input);
+            let inputs = content
+                .parse_terminated::<_, Token![,]>(Ident::parse)?
+                .iter()
+                .map(|ident| {
+                    let kind = ParamType::from_str(&ident.to_string())
+                        .map_err(|err| ParseError::new(ident.span(), err))?;
+                    Ok(Param {
+                        name: "".into(),
+                        kind,
+                    })
+                })
+                .collect::<ParseResult<Vec<_>>>()?;
+
+            Function {
+                name,
+                inputs,
+
+                // NOTE: The output types and const-ness of the function do not
+                //   affect its signature.
+                outputs: vec![],
+                constant: false,
+            }
+        };
+        let signature = function.abi_signature();
+        input.parse::<Token![as]>()?;
+        let alias = {
+            let ident = input.parse::<Ident>()?;
+            ident.to_string()
+        };
+
+        Ok(Method { signature, alias })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    macro_rules! contract_args_result {
+        ($($arg:tt)*) => {{
+            use syn::parse::Parser;
+            <Spanned<ContractArgs> as Parse>::parse
+                .parse2(quote::quote! { $($arg)* })
+        }};
+    }
+    macro_rules! contract_args {
+        ($($arg:tt)*) => {
+            contract_args_result!($($arg)*)
+                .expect("failed to parse contract args")
+                .into_inner()
+        };
+    }
+    macro_rules! contract_args_err {
+        ($($arg:tt)*) => {
+            contract_args_result!($($arg)*)
+                .expect_err("expected parse contract args to error")
+        };
+    }
+
+    fn deployment(network_id: u32, address: &str) -> Deployment {
+        Deployment {
+            network_id,
+            address: parse_address(address).expect("failed to parse deployment address"),
+        }
+    }
+
+    fn method(signature: &str, alias: &str) -> Method {
+        Method {
+            signature: signature.into(),
+            alias: alias.into(),
+        }
+    }
+
+    #[test]
+    fn parse_contract_args() {
+        let args = contract_args!("path/to/artifact.json");
+        assert_eq!(args.artifact_path, "path/to/artifact.json");
+    }
+
+    #[test]
+    fn crate_parameter_accepts_keywords() {
+        let args = contract_args!("artifact.json", crate = crate);
+        assert_eq!(args.parameters, &[Parameter::Crate("crate".into())]);
+    }
+
+    #[test]
+    fn parse_contract_args_with_defaults() {
+        let args = contract_args!("artifact.json");
+        assert_eq!(
+            args,
+            ContractArgs {
+                visibility: None,
+                artifact_path: "artifact.json".into(),
+                parameters: vec![],
+            },
+        );
+    }
+
+    #[test]
+    fn parse_contract_args_with_parameters() {
+        let args = contract_args!(
+            pub(crate) "artifact.json",
+            crate = foobar,
+            mod = contract,
+            contract = Contract,
+            deployments {
+                1 => "0x000102030405060708090a0b0c0d0e0f10111213",
+                4 => "0x0123456789012345678901234567890123456789",
+            },
+            methods {
+                myMethod(uint256, bool) as my_renamed_method;
+                myOtherMethod() as my_other_renamed_method;
+            },
+            event_derives (Asdf, a::B, a::b::c::D)
+        );
+        assert_eq!(
+            args,
+            ContractArgs {
+                visibility: Some(quote!(pub(crate)).to_string()),
+                artifact_path: "artifact.json".into(),
+                parameters: vec![
+                    Parameter::Crate("foobar".into()),
+                    Parameter::Mod("contract".into()),
+                    Parameter::Contract("Contract".into()),
+                    Parameter::Deployments(vec![
+                        deployment(1, "0x000102030405060708090a0b0c0d0e0f10111213"),
+                        deployment(4, "0x0123456789012345678901234567890123456789"),
+                    ]),
+                    Parameter::Methods(vec![
+                        method("myMethod(uint256,bool)", "my_renamed_method"),
+                        method("myOtherMethod()", "my_other_renamed_method"),
+                    ]),
+                    Parameter::EventDerives(vec![
+                        "Asdf".into(),
+                        "a :: B".into(),
+                        "a :: b :: c :: D".into()
+                    ])
+                ],
+            },
+        );
+    }
+
+    #[test]
+    fn duplicate_network_id_error() {
+        contract_args_err!(
+            "artifact.json",
+            deployments {
+                1 => "0x000102030405060708090a0b0c0d0e0f10111213",
+                1 => "0x0123456789012345678901234567890123456789",
+            }
+        );
+    }
+
+    #[test]
+    fn duplicate_method_rename_error() {
+        contract_args_err!(
+            "artifact.json",
+            methods {
+                myMethod(uint256) as my_method_1;
+                myMethod(uint256) as my_method_2;
+            }
+        );
+        contract_args_err!(
+            "artifact.json",
+            methods {
+                myMethod1(uint256) as my_method;
+                myMethod2(uint256) as my_method;
+            }
+        );
+    }
+
+    #[test]
+    fn method_invalid_method_parameter_type() {
+        contract_args_err!(
+            "artifact.json",
+            methods {
+                myMethod(invalid) as my_method;
+            }
+        );
+    }
+}

crates/ethers-derive/src/spanned.rs

@@ -0,0 +1,50 @@
+//! Provides implementation for helpers used in parsing `TokenStream`s where the
+//! data ultimately does not care about its `Span` information, but it is useful
+//! during intermediate processing.
+
+use proc_macro2::Span;
+use std::ops::Deref;
+use syn::parse::{Parse, ParseStream, Result as ParseResult};
+
+/// Trait that abstracts functionality for inner data that can be parsed and
+/// wrapped with a specific `Span`.
+pub trait ParseInner: Sized {
+    fn spanned_parse(input: ParseStream) -> ParseResult<(Span, Self)>;
+}
+
+impl<T: Parse> ParseInner for T {
+    fn spanned_parse(input: ParseStream) -> ParseResult<(Span, Self)> {
+        Ok((input.span(), T::parse(input)?))
+    }
+}
+
+impl<T: ParseInner> Parse for Spanned<T> {
+    fn parse(input: ParseStream) -> ParseResult<Self> {
+        let (span, value) = T::spanned_parse(input)?;
+        Ok(Spanned(span, value))
+    }
+}
+
+/// A struct that captures `Span` information for inner parsable data.
+#[cfg_attr(test, derive(Clone, Debug))]
+pub struct Spanned<T>(Span, T);
+
+impl<T> Spanned<T> {
+    /// Retrieves the captured `Span` information for the parsed data.
+    pub fn span(&self) -> Span {
+        self.0
+    }
+
+    /// Retrieves the inner data.
+    pub fn into_inner(self) -> T {
+        self.1
+    }
+}
+
+impl<T> Deref for Spanned<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        &self.1
+    }
+}

crates/ethers-derive/src/src/contract.rs

@@ -0,0 +1,178 @@
+#![deny(missing_docs)]
+
+//! Crate for generating type-safe bindings to Ethereum smart contracts. This
+//! crate is intended to be used either indirectly with the `ethcontract`
+//! crate's `contract` procedural macro or directly from a build script.
+
+mod common;
+mod deployment;
+mod events;
+mod methods;
+mod types;
+
+use crate::util;
+use crate::Args;
+use anyhow::{anyhow, Context as _, Result};
+use ethcontract_common::{Address, Artifact};
+use inflector::Inflector;
+use proc_macro2::{Ident, Literal, TokenStream};
+use quote::quote;
+use std::collections::HashMap;
+use syn::{Path, Visibility};
+
+/// Internal shared context for generating smart contract bindings.
+pub(crate) struct Context {
+    /// The artifact JSON as string literal.
+    artifact_json: Literal,
+    /// The parsed artifact.
+    artifact: Artifact,
+    /// The identifier for the runtime crate. Usually this is `ethcontract` but
+    /// it can be different if the crate was renamed in the Cargo manifest for
+    /// example.
+    runtime_crate: Ident,
+    /// The visibility for the generated module and re-exported contract type.
+    visibility: Visibility,
+    /// The name of the module as an identifier in which to place the contract
+    /// implementation. Note that the main contract type gets re-exported in the
+    /// root.
+    contract_mod: Ident,
+    /// The contract name as an identifier.
+    contract_name: Ident,
+    /// Additional contract deployments.
+    deployments: HashMap<u32, Address>,
+    /// Manually specified method aliases.
+    method_aliases: HashMap<String, Ident>,
+    /// Derives added to event structs and enums.
+    event_derives: Vec<Path>,
+}
+
+impl Context {
+    /// Create a context from the code generation arguments.
+    fn from_args(args: Args) -> Result<Self> {
+        let (artifact_json, artifact) = {
+            let artifact_json = args
+                .artifact_source
+                .artifact_json()
+                .context("failed to get artifact JSON")?;
+
+            let artifact = Artifact::from_json(&artifact_json)
+                .with_context(|| format!("invalid artifact JSON '{}'", artifact_json))
+                .with_context(|| {
+                    format!(
+                        "failed to parse artifact from source {:?}",
+                        args.artifact_source,
+                    )
+                })?;
+
+            (Literal::string(&artifact_json), artifact)
+        };
+
+        let raw_contract_name = if let Some(name) = args.contract_name_override.as_ref() {
+            name
+        } else if !artifact.contract_name.is_empty() {
+            &artifact.contract_name
+        } else {
+            return Err(anyhow!(
+                "contract artifact is missing a name, this can happen when \
+                 using a source that does not provide a contract name such  as \
+                 Etherscan; in this case the contract must be manually \
+                 specified"
+            ));
+        };
+
+        let runtime_crate = util::ident(&args.runtime_crate_name);
+        let visibility = match args.visibility_modifier.as_ref() {
+            Some(vis) => syn::parse_str(vis)?,
+            None => Visibility::Inherited,
+        };
+        let contract_mod = if let Some(name) = args.contract_mod_override.as_ref() {
+            util::ident(name)
+        } else {
+            util::ident(&raw_contract_name.to_snake_case())
+        };
+        let contract_name = util::ident(raw_contract_name);
+
+        // NOTE: We only check for duplicate signatures here, since if there are
+        //   duplicate aliases, the compiler will produce a warning because a
+        //   method will be re-defined.
+        let mut method_aliases = HashMap::new();
+        for (signature, alias) in args.method_aliases.into_iter() {
+            let alias = syn::parse_str(&alias)?;
+            if method_aliases.insert(signature.clone(), alias).is_some() {
+                return Err(anyhow!(
+                    "duplicate method signature '{}' in method aliases",
+                    signature,
+                ));
+            }
+        }
+
+        let event_derives = args
+            .event_derives
+            .iter()
+            .map(|derive| syn::parse_str::<Path>(derive))
+            .collect::<Result<Vec<_>, _>>()
+            .context("failed to parse event derives")?;
+
+        Ok(Context {
+            artifact_json,
+            artifact,
+            runtime_crate,
+            visibility,
+            contract_mod,
+            contract_name,
+            deployments: args.deployments,
+            method_aliases,
+            event_derives,
+        })
+    }
+}
+
+#[cfg(test)]
+impl Default for Context {
+    fn default() -> Self {
+        Context {
+            artifact_json: Literal::string("{}"),
+            artifact: Artifact::empty(),
+            runtime_crate: util::ident("ethcontract"),
+            visibility: Visibility::Inherited,
+            contract_mod: util::ident("contract"),
+            contract_name: util::ident("Contract"),
+            deployments: HashMap::new(),
+            method_aliases: HashMap::new(),
+            event_derives: Vec::new(),
+        }
+    }
+}
+
+pub(crate) fn expand(args: Args) -> Result<TokenStream> {
+    let cx = Context::from_args(args)?;
+    let contract = expand_contract(&cx).context("error expanding contract from its ABI")?;
+
+    Ok(contract)
+}
+
+fn expand_contract(cx: &Context) -> Result<TokenStream> {
+    let runtime_crate = &cx.runtime_crate;
+    let vis = &cx.visibility;
+    let contract_mod = &cx.contract_mod;
+    let contract_name = &cx.contract_name;
+
+    let common = common::expand(cx);
+    let deployment = deployment::expand(cx)?;
+    let methods = methods::expand(cx)?;
+    let events = events::expand(cx)?;
+
+    Ok(quote! {
+        #[allow(dead_code)]
+        #vis mod #contract_mod {
+            #[rustfmt::skip]
+            use #runtime_crate as ethcontract;
+
+            #common
+            #deployment
+            #methods
+            #events
+        }
+        #vis use self::#contract_mod::Contract as #contract_name;
+    })
+}

crates/ethers-derive/src/src/contract/common.rs

@@ -0,0 +1,200 @@
+use crate::contract::Context;
+use crate::util::expand_doc;
+use ethcontract_common::Address;
+use proc_macro2::{Literal, TokenStream};
+use quote::quote;
+
+pub(crate) fn expand(cx: &Context) -> TokenStream {
+    let artifact_json = &cx.artifact_json;
+    let contract_name = &cx.contract_name;
+
+    let doc_str = cx
+        .artifact
+        .devdoc
+        .details
+        .as_deref()
+        .unwrap_or("Generated by `ethcontract`");
+    let doc = expand_doc(doc_str);
+
+    let deployments = cx.deployments.iter().map(|(network_id, address)| {
+        let network_id = Literal::string(&network_id.to_string());
+        let address = expand_address(*address);
+
+        quote! {
+            artifact.networks.insert(
+                #network_id.to_owned(),
+                self::ethcontract::common::truffle::Network {
+                    address: #address,
+                    transaction_hash: None,
+                },
+            );
+        }
+    });
+
+    quote! {
+        #doc
+        #[derive(Clone)]
+        pub struct Contract {
+            methods: Methods,
+        }
+
+        impl Contract {
+            /// Retrieves the truffle artifact used to generate the type safe
+            /// API for this contract.
+            pub fn artifact() -> &'static self::ethcontract::Artifact {
+                use self::ethcontract::private::lazy_static;
+                use self::ethcontract::Artifact;
+
+                lazy_static! {
+                    pub static ref ARTIFACT: Artifact = {
+                        #[allow(unused_mut)]
+                        let mut artifact = Artifact::from_json(#artifact_json)
+                            .expect("valid artifact JSON");
+                        #( #deployments )*
+
+                        artifact
+                    };
+                }
+                &ARTIFACT
+            }
+
+            /// Creates a new contract instance with the specified `web3`
+            /// provider at the given `Address`.
+            ///
+            /// Note that this does not verify that a contract with a maching
+            /// `Abi` is actually deployed at the given address.
+            pub fn at<F, T>(
+                web3: &self::ethcontract::web3::api::Web3<T>,
+                address: self::ethcontract::Address,
+            ) -> Self
+            where
+                F: self::ethcontract::web3::futures::Future<
+                    Item = self::ethcontract::json::Value,
+                    Error = self::ethcontract::web3::Error,
+                > + Send + 'static,
+                T: self::ethcontract::web3::Transport<Out = F> + Send + Sync + 'static,
+            {
+                Contract::with_transaction(web3, address, None)
+            }
+
+
+            /// Creates a new contract instance with the specified `web3` provider with
+            /// the given `Abi` at the given `Address` and an optional transaction hash.
+            /// This hash is used to retrieve contract related information such as the
+            /// creation block (which is useful for fetching all historic events).
+            ///
+            /// Note that this does not verify that a contract with a matching `Abi` is
+            /// actually deployed at the given address nor that the transaction hash,
+            /// when provided, is actually for this contract deployment.
+            pub fn with_transaction<F, T>(
+                web3: &self::ethcontract::web3::api::Web3<T>,
+                address: self::ethcontract::Address,
+                transaction_hash: Option<self::ethcontract::H256>,
+            ) -> Self
+            where
+                F: self::ethcontract::web3::futures::Future<
+                    Item = self::ethcontract::json::Value,
+                    Error = self::ethcontract::web3::Error,
+                > + Send + 'static,
+                T: self::ethcontract::web3::Transport<Out = F> + Send + Sync + 'static,
+            {
+                use self::ethcontract::Instance;
+                use self::ethcontract::transport::DynTransport;
+                use self::ethcontract::web3::api::Web3;
+
+                let transport = DynTransport::new(web3.transport().clone());
+                let web3 = Web3::new(transport);
+                let abi = Self::artifact().abi.clone();
+                let instance = Instance::with_transaction(web3, abi, address, transaction_hash);
+
+                Contract::from_raw(instance)
+            }
+
+            /// Creates a contract from a raw instance.
+            fn from_raw(instance: self::ethcontract::dyns::DynInstance) -> Self {
+                let methods = Methods { instance };
+                Contract { methods }
+            }
+
+            /// Returns the contract address being used by this instance.
+            pub fn address(&self) -> self::ethcontract::Address {
+                self.raw_instance().address()
+            }
+
+            /// Returns the hash for the transaction that deployed the contract
+            /// if it is known, `None` otherwise.
+            pub fn transaction_hash(&self) -> Option<self::ethcontract::H256> {
+                self.raw_instance().transaction_hash()
+            }
+
+            /// Returns a reference to the default method options used by this
+            /// contract.
+            pub fn defaults(&self) -> &self::ethcontract::contract::MethodDefaults {
+                &self.raw_instance().defaults
+            }
+
+            /// Returns a mutable reference to the default method options used
+            /// by this contract.
+            pub fn defaults_mut(&mut self) -> &mut self::ethcontract::contract::MethodDefaults {
+                &mut self.raw_instance_mut().defaults
+            }
+
+            /// Returns a reference to the raw runtime instance used by this
+            /// contract.
+            pub fn raw_instance(&self) -> &self::ethcontract::dyns::DynInstance {
+                &self.methods.instance
+            }
+
+            /// Returns a mutable reference to the raw runtime instance used by
+            /// this contract.
+            fn raw_instance_mut(&mut self) -> &mut self::ethcontract::dyns::DynInstance {
+                &mut self.methods.instance
+            }
+        }
+
+        impl std::fmt::Debug for Contract {
+            fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+                f.debug_tuple(stringify!(#contract_name))
+                    .field(&self.address())
+                    .finish()
+            }
+        }
+    }
+}
+
+/// Expands an `Address` into a literal representation that can be used with
+/// quasi-quoting for code generation.
+fn expand_address(address: Address) -> TokenStream {
+    let bytes = address
+        .as_bytes()
+        .iter()
+        .copied()
+        .map(Literal::u8_unsuffixed);
+
+    quote! {
+        self::ethcontract::H160([#( #bytes ),*])
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    #[rustfmt::skip]
+    fn expand_address_value() {
+        assert_quote!(
+            expand_address(Address::zero()),
+            {
+                self::ethcontract::H160([ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ])
+            },
+        );
+
+        assert_quote!(
+            expand_address("000102030405060708090a0b0c0d0e0f10111213".parse().unwrap()),
+            {
+                self::ethcontract::H160([0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19])
+            },
+        );
+    }
+}

crates/ethers-derive/src/src/contract/deployment.rs

@@ -0,0 +1,167 @@
+use crate::contract::{methods, Context};
+use crate::util;
+use anyhow::{Context as _, Result};
+use inflector::Inflector;
+use proc_macro2::{Literal, TokenStream};
+use quote::quote;
+
+pub(crate) fn expand(cx: &Context) -> Result<TokenStream> {
+    let deployed = expand_deployed(&cx);
+    let deploy =
+        expand_deploy(&cx).context("error generating contract `deploy` associated function")?;
+
+    Ok(quote! {
+        #deployed
+        #deploy
+    })
+}
+
+fn expand_deployed(cx: &Context) -> TokenStream {
+    if cx.artifact.networks.is_empty() && cx.deployments.is_empty() {
+        return quote! {};
+    }
+
+    quote! {
+        impl Contract {
+            /// Locates a deployed contract based on the current network ID
+            /// reported by the `web3` provider.
+            ///
+            /// Note that this does not verify that a contract with a maching
+            /// `Abi` is actually deployed at the given address.
+            pub async fn deployed<F, T>(
+                web3: &self::ethcontract::web3::api::Web3<T>,
+            ) -> Result<Self, self::ethcontract::errors::DeployError>
+            where
+                F: self::ethcontract::web3::futures::Future<
+                    Item = self::ethcontract::json::Value,
+                    Error = self::ethcontract::web3::Error
+                > + Send + 'static,
+                T: self::ethcontract::web3::Transport<Out = F> + Send + Sync + 'static,
+            {
+                use self::ethcontract::{Instance, Web3};
+                use self::ethcontract::transport::DynTransport;
+
+                let transport = DynTransport::new(web3.transport().clone());
+                let web3 = Web3::new(transport);
+                let instance = Instance::deployed(web3, Contract::artifact().clone()).await?;
+
+                Ok(Contract::from_raw(instance))
+            }
+        }
+    }
+}
+
+fn expand_deploy(cx: &Context) -> Result<TokenStream> {
+    if cx.artifact.bytecode.is_empty() {
+        // do not generate deploy method for contracts that have empty bytecode
+        return Ok(quote! {});
+    }
+
+    // TODO(nlordell): not sure how contructor documentation get generated as I
+    //   can't seem to get truffle to output it
+    let doc = util::expand_doc("Generated by `ethcontract`");
+
+    let (input, arg) = match cx.artifact.abi.constructor() {
+        Some(contructor) => (
+            methods::expand_inputs(&contructor.inputs)?,
+            methods::expand_inputs_call_arg(&contructor.inputs),
+        ),
+        None => (quote! {}, quote! {()}),
+    };
+
+    let libs: Vec<_> = cx
+        .artifact
+        .bytecode
+        .undefined_libraries()
+        .map(|name| (name, util::safe_ident(&name.to_snake_case())))
+        .collect();
+    let (lib_struct, lib_input, link) = if !libs.is_empty() {
+        let lib_struct = {
+            let lib_struct_fields = libs.iter().map(|(name, field)| {
+                let doc = util::expand_doc(&format!("Address of the `{}` library.", name));
+
+                quote! {
+                    #doc pub #field: self::ethcontract::Address
+                }
+            });
+
+            quote! {
+                /// Undefinied libraries in the contract bytecode that are
+                /// required for linking in order to deploy.
+                pub struct Libraries {
+                    #( #lib_struct_fields, )*
+                }
+            }
+        };
+
+        let link = {
+            let link_libraries = libs.iter().map(|(name, field)| {
+                let name_lit = Literal::string(&name);
+
+                quote! {
+                    bytecode.link(#name_lit, libs.#field).expect("valid library");
+                }
+            });
+
+            quote! {
+                let mut bytecode = bytecode;
+                #( #link_libraries )*
+            }
+        };
+
+        (lib_struct, quote! { , libs: Libraries }, link)
+    } else {
+        Default::default()
+    };
+
+    Ok(quote! {
+        #lib_struct
+
+        impl Contract {
+            #doc
+            pub fn builder<F, T>(
+                web3: &self::ethcontract::web3::api::Web3<T> #lib_input #input ,
+            ) -> self::ethcontract::dyns::DynDeployBuilder<Self>
+            where
+                F: self::ethcontract::web3::futures::Future<
+                    Item = self::ethcontract::json::Value,
+                    Error = self::ethcontract::web3::Error,
+                > + Send + 'static,
+                T: self::ethcontract::web3::Transport<Out = F> + Send + Sync + 'static,
+            {
+                use self::ethcontract::dyns::DynTransport;
+                use self::ethcontract::contract::DeployBuilder;
+                use self::ethcontract::web3::api::Web3;
+
+                let transport = DynTransport::new(web3.transport().clone());
+                let web3 = Web3::new(transport);
+
+                let bytecode = Self::artifact().bytecode.clone();
+                #link
+
+                DeployBuilder::new(web3, bytecode, #arg).expect("valid deployment args")
+            }
+        }
+
+        impl self::ethcontract::contract::Deploy<self::ethcontract::dyns::DynTransport> for Contract {
+            type Context = self::ethcontract::common::Bytecode;
+
+            fn bytecode(cx: &Self::Context) -> &self::ethcontract::common::Bytecode {
+                cx
+            }
+
+            fn abi(_: &Self::Context) -> &self::ethcontract::common::Abi {
+                &Self::artifact().abi
+            }
+
+            fn from_deployment(
+                web3: self::ethcontract::dyns::DynWeb3,
+                address: self::ethcontract::Address,
+                transaction_hash: self::ethcontract::H256,
+                _: Self::Context,
+            ) -> Self {
+                Self::with_transaction(&web3, address, Some(transaction_hash))
+            }
+        }
+    })
+}

crates/ethers-derive/src/src/contract/events.rs

@@ -0,0 +1,855 @@
+use crate::contract::{types, Context};
+use crate::util;
+use anyhow::Result;
+use ethcontract_common::abi::{Event, EventParam, Hash, ParamType};
+use ethcontract_common::abiext::EventExt;
+use inflector::Inflector;
+use proc_macro2::{Literal, TokenStream};
+use quote::quote;
+use syn::Path;
+
+pub(crate) fn expand(cx: &Context) -> Result<TokenStream> {
+    let structs_mod = expand_structs_mod(cx)?;
+    let filters = expand_filters(cx)?;
+    let all_events = expand_all_events(cx);
+
+    Ok(quote! {
+        #structs_mod
+        #filters
+        #all_events
+    })
+}
+
+/// Expands into a module containing all the event data structures from the ABI.
+fn expand_structs_mod(cx: &Context) -> Result<TokenStream> {
+    let data_types = cx
+        .artifact
+        .abi
+        .events()
+        .map(|event| expand_data_type(event, &cx.event_derives))
+        .collect::<Result<Vec<_>>>()?;
+    if data_types.is_empty() {
+        return Ok(quote! {});
+    }
+
+    Ok(quote! {
+        /// Module containing all generated data models for this contract's
+        /// events.
+        pub mod event_data {
+            use super::ethcontract;
+
+            #( #data_types )*
+        }
+    })
+}
+
+fn expand_derives(derives: &[Path]) -> TokenStream {
+    quote! {#(#derives),*}
+}
+
+/// Expands an ABI event into a single event data type. This can expand either
+/// into a structure or a tuple in the case where all event parameters (topics
+/// and data) are anonymous.
+fn expand_data_type(event: &Event, event_derives: &[Path]) -> Result<TokenStream> {
+    let event_name = expand_struct_name(event);
+
+    let signature = expand_hash(event.signature());
+
+    let abi_signature = event.abi_signature();
+    let abi_signature_lit = Literal::string(&abi_signature);
+    let abi_signature_doc = util::expand_doc(&format!("`{}`", abi_signature));
+
+    let params = expand_params(event)?;
+
+    let all_anonymous_fields = event.inputs.iter().all(|input| input.name.is_empty());
+    let (data_type_definition, data_type_construction) = if all_anonymous_fields {
+        expand_data_tuple(&event_name, &params)
+    } else {
+        expand_data_struct(&event_name, &params)
+    };
+
+    let params_len = Literal::usize_unsuffixed(params.len());
+    let read_param_token = params
+        .iter()
+        .map(|(name, ty)| {
+            quote! {
+                let #name = <#ty as self::ethcontract::web3::contract::tokens::Tokenizable>
+                    ::from_token(tokens.next().unwrap())?;
+            }
+        })
+        .collect::<Vec<_>>();
+
+    let derives = expand_derives(event_derives);
+
+    Ok(quote! {
+        #[derive(Clone, Debug, Default, Eq, PartialEq, #derives)]
+        pub #data_type_definition
+
+        impl #event_name {
+            /// Retrieves the signature for the event this data corresponds to.
+            /// This signature is the Keccak-256 hash of the ABI signature of
+            /// this event.
+            pub fn signature() -> self::ethcontract::H256 {
+                #signature
+            }
+
+            /// Retrieves the ABI signature for the event this data corresponds
+            /// to. For this event the value should always be:
+            ///
+            #abi_signature_doc
+            pub fn abi_signature() -> &'static str {
+                #abi_signature_lit
+            }
+        }
+
+        impl self::ethcontract::web3::contract::tokens::Detokenize for #event_name {
+            fn from_tokens(
+                tokens: Vec<self::ethcontract::common::abi::Token>,
+            ) -> Result<Self, self::ethcontract::web3::contract::Error> {
+                if tokens.len() != #params_len {
+                    return Err(self::ethcontract::web3::contract::Error::InvalidOutputType(format!(
+                        "Expected {} tokens, got {}: {:?}",
+                        #params_len,
+                        tokens.len(),
+                        tokens
+                    )));
+                }
+
+                #[allow(unused_mut)]
+                let mut tokens = tokens.into_iter();
+                #( #read_param_token )*
+
+                Ok(#data_type_construction)
+            }
+        }
+    })
+}
+
+/// Expands an ABI event into an identifier for its event data type.
+fn expand_struct_name(event: &Event) -> TokenStream {
+    let event_name = util::ident(&event.name.to_pascal_case());
+    quote! { #event_name }
+}
+
+/// Expands an ABI event into name-type pairs for each of its parameters.
+fn expand_params(event: &Event) -> Result<Vec<(TokenStream, TokenStream)>> {
+    event
+        .inputs
+        .iter()
+        .enumerate()
+        .map(|(i, input)| {
+            // NOTE: Events can contain nameless values.
+            let name = util::expand_input_name(i, &input.name);
+            let ty = expand_input_type(&input)?;
+
+            Ok((name, ty))
+        })
+        .collect()
+}
+
+/// Expands an event data structure from its name-type parameter pairs. Returns
+/// a tuple with the type definition (i.e. the struct declaration) and
+/// construction (i.e. code for creating an instance of the event data).
+fn expand_data_struct(
+    name: &TokenStream,
+    params: &[(TokenStream, TokenStream)],
+) -> (TokenStream, TokenStream) {
+    let fields = params
+        .iter()
+        .map(|(name, ty)| quote! { pub #name: #ty })
+        .collect::<Vec<_>>();
+
+    let param_names = params
+        .iter()
+        .map(|(name, _)| name)
+        .cloned()
+        .collect::<Vec<_>>();
+
+    let definition = quote! { struct #name { #( #fields, )* } };
+    let construction = quote! { #name { #( #param_names ),* } };
+
+    (definition, construction)
+}
+
+/// Expands an event data named tuple from its name-type parameter pairs.
+/// Returns a tuple with the type definition and construction.
+fn expand_data_tuple(
+    name: &TokenStream,
+    params: &[(TokenStream, TokenStream)],
+) -> (TokenStream, TokenStream) {
+    let fields = params
+        .iter()
+        .map(|(_, ty)| quote! { pub #ty })
+        .collect::<Vec<_>>();
+
+    let param_names = params
+        .iter()
+        .map(|(name, _)| name)
+        .cloned()
+        .collect::<Vec<_>>();
+
+    let definition = quote! { struct #name( #( #fields ),* ); };
+    let construction = quote! { #name( #( #param_names ),* ) };
+
+    (definition, construction)
+}
+
+/// Expands into an `Events` type with method definitions for creating event
+/// streams for all non-anonymous contract events in the ABI.
+fn expand_filters(cx: &Context) -> Result<TokenStream> {
+    let standard_events = cx
+        .artifact
+        .abi
+        .events()
+        .filter(|event| !event.anonymous)
+        .collect::<Vec<_>>();
+    if standard_events.is_empty() {
+        return Ok(quote! {});
+    }
+
+    let filters = standard_events
+        .iter()
+        .map(|event| expand_filter(event))
+        .collect::<Result<Vec<_>>>()?;
+    let builders = standard_events
+        .iter()
+        .map(|event| expand_builder_type(event))
+        .collect::<Result<Vec<_>>>()?;
+
+    Ok(quote! {
+        impl Contract {
+            /// Retrieves a handle to a type containing for creating event
+            /// streams for all the contract events.
+            pub fn events(&self) -> Events<'_> {
+                Events {
+                    instance: self.raw_instance(),
+                }
+            }
+        }
+
+        pub struct Events<'a> {
+            instance: &'a self::ethcontract::dyns::DynInstance,
+        }
+
+        impl Events<'_> {
+            #( #filters )*
+        }
+
+        /// Module containing the generated event stream builders with type safe
+        /// filter methods for this contract's events.
+        pub mod event_builders {
+            use super::ethcontract;
+            use super::event_data;
+
+            #( #builders )*
+        }
+    })
+}
+
+/// Expands into a single method for contracting an event stream.
+fn expand_filter(event: &Event) -> Result<TokenStream> {
+    let name = util::safe_ident(&event.name.to_snake_case());
+    let builder_name = expand_builder_name(event);
+    let signature = expand_hash(event.signature());
+
+    Ok(quote! {
+        /// Generated by `ethcontract`.
+        pub fn #name(&self) -> self::event_builders::#builder_name {
+            self::event_builders::#builder_name(
+                self.instance.event(#signature)
+                    .expect("generated event filter"),
+            )
+        }
+    })
+}
+
+/// Expands an ABI event into a wrapped `EventBuilder` type with type-safe
+/// filter methods.
+fn expand_builder_type(event: &Event) -> Result<TokenStream> {
+    let event_name = expand_struct_name(event);
+    let builder_doc = util::expand_doc(&format!(
+        "A builder for creating a filtered stream of `{}` events.",
+        event_name
+    ));
+    let builder_name = expand_builder_name(event);
+    let topic_filters = expand_builder_topic_filters(event)?;
+
+    Ok(quote! {
+        #builder_doc
+        pub struct #builder_name(
+            /// The inner event builder.
+            pub self::ethcontract::dyns::DynEventBuilder<self::event_data::#event_name>,
+        );
+
+        impl #builder_name {
+            /// Sets the starting block from which to stream logs for.
+            ///
+            /// If left unset defaults to the latest block.
+            #[allow(clippy::wrong_self_convention)]
+            pub fn from_block(mut self, block: self::ethcontract::BlockNumber) -> Self {
+                self.0 = (self.0).from_block(block);
+                self
+            }
+
+            /// Sets the last block from which to stream logs for.
+            ///
+            /// If left unset defaults to the streaming until the end of days.
+            #[allow(clippy::wrong_self_convention)]
+            pub fn to_block(mut self, block: self::ethcontract::BlockNumber) -> Self {
+                self.0 = (self.0).to_block(block);
+                self
+            }
+
+            /// Limit the number of events that can be retrieved by this filter.
+            ///
+            /// Note that this parameter is non-standard.
+            pub fn limit(mut self, value: usize) -> Self {
+                self.0 = (self.0).limit(value);
+                self
+            }
+
+            /// The polling interval. This is used as the interval between
+            /// consecutive `eth_getFilterChanges` calls to get filter updates.
+            pub fn poll_interval(mut self, value: std::time::Duration) -> Self {
+                self.0 = (self.0).poll_interval(value);
+                self
+            }
+
+            #topic_filters
+
+            /// Returns a future that resolves with a collection of all existing
+            /// logs matching the builder parameters.
+            pub async fn query(self) -> std::result::Result<
+                std::vec::Vec<self::ethcontract::Event<self::event_data::#event_name>>,
+                self::ethcontract::errors::EventError,
+            > {
+                (self.0).query().await
+            }
+
+            /// Creates an event stream from the current event builder.
+            pub fn stream(self) -> impl self::ethcontract::futures::stream::Stream<
+                Item = std::result::Result<
+                    self::ethcontract::StreamEvent<self::event_data::#event_name>,
+                    self::ethcontract::errors::EventError,
+                >,
+            > {
+                (self.0).stream()
+            }
+        }
+    })
+}
+
+/// Expands an ABI event into filter methods for its indexed parameters.
+fn expand_builder_topic_filters(event: &Event) -> Result<TokenStream> {
+    let topic_filters = event
+        .inputs
+        .iter()
+        .filter(|input| input.indexed)
+        .enumerate()
+        .map(|(topic_index, input)| expand_builder_topic_filter(topic_index, input))
+        .collect::<Result<Vec<_>>>()?;
+
+    Ok(quote! {
+        #( #topic_filters )*
+    })
+}
+
+/// Expands a event parameter into an event builder filter method for the
+/// specified topic index.
+fn expand_builder_topic_filter(topic_index: usize, param: &EventParam) -> Result<TokenStream> {
+    let doc = util::expand_doc(&format!(
+        "Adds a filter for the {} event parameter.",
+        param.name,
+    ));
+    let topic = util::ident(&format!("topic{}", topic_index));
+    let name = if param.name.is_empty() {
+        topic.clone()
+    } else {
+        util::safe_ident(&param.name.to_snake_case())
+    };
+    let ty = expand_input_type(&param)?;
+
+    Ok(quote! {
+        #doc
+        pub fn #name(mut self, topic: self::ethcontract::Topic<#ty>) -> Self {
+            self.0 = (self.0).#topic(topic);
+            self
+        }
+    })
+}
+
+/// Expands an ABI event into an identifier for its event data type.
+fn expand_builder_name(event: &Event) -> TokenStream {
+    let builder_name = util::ident(&format!("{}Builder", &event.name.to_pascal_case()));
+    quote! { #builder_name }
+}
+
+/// Expands into the `all_events` method on the root contract type if it
+/// contains events. Expands to nothing otherwise.
+fn expand_all_events(cx: &Context) -> TokenStream {
+    if cx.artifact.abi.events.is_empty() {
+        return quote! {};
+    }
+
+    let event_enum = expand_event_enum(cx);
+    let event_parse_log = expand_event_parse_log(cx);
+
+    quote! {
+        impl Contract {
+            /// Returns a log stream with all events.
+            pub fn all_events(&self) -> self::ethcontract::dyns::DynAllEventsBuilder<Event> {
+                self::ethcontract::dyns::DynAllEventsBuilder::new(
+                    self.raw_instance().web3(),
+                    self.address(),
+                    self.transaction_hash(),
+                )
+            }
+        }
+
+        #event_enum
+        #event_parse_log
+    }
+}
+
+/// Expands into an enum with one variant for each distinct event type,
+/// including anonymous types.
+fn expand_event_enum(cx: &Context) -> TokenStream {
+    let variants = {
+        let mut events = cx.artifact.abi.events().collect::<Vec<_>>();
+
+        // NOTE: We sort the events by name so that the generated enum is
+        //   consistent. This also faciliates testing as so that the same ABI
+        //   yields consistent code.
+        events.sort_unstable_by_key(|event| &event.name);
+
+        events
+            .into_iter()
+            .map(|event| {
+                let struct_name = expand_struct_name(&event);
+                quote! {
+                    #struct_name(self::event_data::#struct_name)
+                }
+            })
+            .collect::<Vec<_>>()
+    };
+
+    let derives = expand_derives(&cx.event_derives);
+
+    quote! {
+        /// A contract event.
+        #[derive(Clone, Debug, Eq, PartialEq, #derives)]
+        pub enum Event {
+            #( #variants, )*
+        }
+    }
+}
+
+/// Expands the `ParseLog` implementation for the event enum.
+fn expand_event_parse_log(cx: &Context) -> TokenStream {
+    let all_events = {
+        let mut all_events = cx
+            .artifact
+            .abi
+            .events()
+            .map(|event| {
+                let struct_name = expand_struct_name(&event);
+
+                let name = Literal::string(&event.name);
+                let decode_event = quote! {
+                    log.clone().decode(
+                        &Contract::artifact()
+                            .abi
+                            .event(#name)
+                            .expect("generated event decode")
+                    )
+                };
+
+                (event, struct_name, decode_event)
+            })
+            .collect::<Vec<_>>();
+
+        // NOTE: We sort the events by name so that the anonymous error decoding
+        //   is consistent. Since the events are stored in a `HashMap`, there is
+        //   no guaranteed order, and in the case where there is ambiguity in
+        //   decoding anonymous events, its nice if they follow some strict and
+        //   predictable order.
+        all_events.sort_unstable_by_key(|(event, _, _)| &event.name);
+        all_events
+    };
+
+    let standard_event_match_arms = all_events
+        .iter()
+        .filter(|(event, _, _)| !event.anonymous)
+        .map(|(event, struct_name, decode_event)| {
+            // These are all possible stardard (i.e. non-anonymous) events that
+            // the contract can produce, along with its signature and index in
+            // the contract ABI. For these, we match topic 0 to the signature
+            // and try to decode.
+
+            let signature = expand_hash(event.signature());
+            quote! {
+                #signature => Ok(Event::#struct_name(#decode_event?)),
+            }
+        })
+        .collect::<Vec<_>>();
+
+    let anonymous_event_try_decode = all_events
+        .iter()
+        .filter(|(event, _, _)| event.anonymous)
+        .map(|(_, struct_name, decode_event)| {
+            // For anonymous events, just try to decode one at a time and return
+            // the first that succeeds.
+
+            quote! {
+                if let Ok(data) = #decode_event {
+                    return Ok(Event::#struct_name(data));
+                }
+            }
+        })
+        .collect::<Vec<_>>();
+
+    let invalid_data = expand_invalid_data();
+
+    quote! {
+        impl self::ethcontract::contract::ParseLog for Event {
+            fn parse_log(
+                log: self::ethcontract::RawLog,
+            ) -> Result<Self, self::ethcontract::errors::ExecutionError> {
+                let standard_event = log.topics
+                    .get(0)
+                    .copied()
+                    .map(|topic| match topic {
+                        #( #standard_event_match_arms )*
+                        _ => #invalid_data,
+                    });
+
+                if let Some(Ok(data)) = standard_event {
+                    return Ok(data);
+                }
+
+                #( #anonymous_event_try_decode )*
+
+                #invalid_data
+            }
+        }
+    }
+}
+
+/// Expands an event property type.
+///
+/// Note that this is slightly different than an expanding a Solidity type as
+/// complex types like arrays and strings get emited as hashes when they are
+/// indexed.
+fn expand_input_type(input: &EventParam) -> Result<TokenStream> {
+    Ok(match (&input.kind, input.indexed) {
+        (ParamType::Array(..), true)
+        | (ParamType::Bytes, true)
+        | (ParamType::FixedArray(..), true)
+        | (ParamType::String, true)
+        | (ParamType::Tuple(..), true) => {
+            quote! { self::ethcontract::H256 }
+        }
+        (kind, _) => types::expand(kind)?,
+    })
+}
+
+/// Expands a 256-bit `Hash` into a literal representation that can be used with
+/// quasi-quoting for code generation.
+fn expand_hash(hash: Hash) -> TokenStream {
+    let bytes = hash.as_bytes().iter().copied().map(Literal::u8_unsuffixed);
+
+    quote! {
+        self::ethcontract::H256([#( #bytes ),*])
+    }
+}
+
+/// Expands to a generic `InvalidData` error.
+fn expand_invalid_data() -> TokenStream {
+    quote! {
+        Err(self::ethcontract::errors::ExecutionError::from(
+            self::ethcontract::common::abi::Error::InvalidData
+        ))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ethcontract_common::abi::{EventParam, ParamType};
+
+    #[test]
+    fn expand_empty_filters() {
+        assert_quote!(expand_filters(&Context::default()).unwrap(), {});
+    }
+
+    #[test]
+    fn expand_transfer_filter() {
+        let event = Event {
+            name: "Transfer".into(),
+            inputs: vec![
+                EventParam {
+                    name: "from".into(),
+                    kind: ParamType::Address,
+                    indexed: true,
+                },
+                EventParam {
+                    name: "to".into(),
+                    kind: ParamType::Address,
+                    indexed: true,
+                },
+                EventParam {
+                    name: "amount".into(),
+                    kind: ParamType::Uint(256),
+                    indexed: false,
+                },
+            ],
+            anonymous: false,
+        };
+        let signature = expand_hash(event.signature());
+
+        assert_quote!(expand_filter(&event).unwrap(), {
+            /// Generated by `ethcontract`.
+            pub fn transfer(&self) -> self::event_builders::TransferBuilder {
+                self::event_builders::TransferBuilder(
+                    self.instance.event(#signature)
+                        .expect("generated event filter"),
+                )
+            }
+        });
+    }
+
+    #[test]
+    fn expand_transfer_builder_topic_filters() {
+        let event = Event {
+            name: "Transfer".into(),
+            inputs: vec![
+                EventParam {
+                    name: "from".into(),
+                    kind: ParamType::Address,
+                    indexed: true,
+                },
+                EventParam {
+                    name: "to".into(),
+                    kind: ParamType::Address,
+                    indexed: true,
+                },
+                EventParam {
+                    name: "amount".into(),
+                    kind: ParamType::Uint(256),
+                    indexed: false,
+                },
+            ],
+            anonymous: false,
+        };
+
+        #[rustfmt::skip]
+        assert_quote!(expand_builder_topic_filters(&event).unwrap(), {
+            #[doc = "Adds a filter for the from event parameter."]
+            pub fn from(mut self, topic: self::ethcontract::Topic<self::ethcontract::Address>) -> Self {
+                self.0 = (self.0).topic0(topic);
+                self
+            }
+
+            #[doc = "Adds a filter for the to event parameter."]
+            pub fn to(mut self, topic: self::ethcontract::Topic<self::ethcontract::Address>) -> Self {
+                self.0 = (self.0).topic1(topic);
+                self
+            }
+        });
+    }
+
+    #[test]
+    fn expand_data_struct_value() {
+        let event = Event {
+            name: "Foo".into(),
+            inputs: vec![
+                EventParam {
+                    name: "a".into(),
+                    kind: ParamType::Bool,
+                    indexed: false,
+                },
+                EventParam {
+                    name: String::new(),
+                    kind: ParamType::Address,
+                    indexed: false,
+                },
+            ],
+            anonymous: false,
+        };
+
+        let name = expand_struct_name(&event);
+        let params = expand_params(&event).unwrap();
+        let (definition, construction) = expand_data_struct(&name, &params);
+
+        assert_quote!(definition, {
+            struct Foo {
+                pub a: bool,
+                pub p1: self::ethcontract::Address,
+            }
+        });
+        assert_quote!(construction, { Foo { a, p1 } });
+    }
+
+    #[test]
+    fn expand_data_tuple_value() {
+        let event = Event {
+            name: "Foo".into(),
+            inputs: vec![
+                EventParam {
+                    name: String::new(),
+                    kind: ParamType::Bool,
+                    indexed: false,
+                },
+                EventParam {
+                    name: String::new(),
+                    kind: ParamType::Address,
+                    indexed: false,
+                },
+            ],
+            anonymous: false,
+        };
+
+        let name = expand_struct_name(&event);
+        let params = expand_params(&event).unwrap();
+        let (definition, construction) = expand_data_tuple(&name, &params);
+
+        assert_quote!(definition, {
+            struct Foo(pub bool, pub self::ethcontract::Address);
+        });
+        assert_quote!(construction, { Foo(p0, p1) });
+    }
+
+    #[test]
+    fn expand_enum_for_all_events() {
+        let context = {
+            let mut context = Context::default();
+            context.artifact.abi.events.insert(
+                "Foo".into(),
+                vec![Event {
+                    name: "Foo".into(),
+                    inputs: vec![EventParam {
+                        name: String::new(),
+                        kind: ParamType::Bool,
+                        indexed: false,
+                    }],
+                    anonymous: false,
+                }],
+            );
+            context.artifact.abi.events.insert(
+                "Bar".into(),
+                vec![Event {
+                    name: "Bar".into(),
+                    inputs: vec![EventParam {
+                        name: String::new(),
+                        kind: ParamType::Address,
+                        indexed: false,
+                    }],
+                    anonymous: true,
+                }],
+            );
+            context.event_derives = ["Asdf", "a::B", "a::b::c::D"]
+                .iter()
+                .map(|derive| syn::parse_str::<Path>(derive).unwrap())
+                .collect();
+            context
+        };
+
+        assert_quote!(expand_event_enum(&context), {
+            /// A contract event.
+            #[derive(Clone, Debug, Eq, PartialEq, Asdf, a::B, a::b::c::D)]
+            pub enum Event {
+                Bar(self::event_data::Bar),
+                Foo(self::event_data::Foo),
+            }
+        });
+    }
+
+    #[test]
+    fn expand_parse_log_impl_for_all_events() {
+        let context = {
+            let mut context = Context::default();
+            context.artifact.abi.events.insert(
+                "Foo".into(),
+                vec![Event {
+                    name: "Foo".into(),
+                    inputs: vec![EventParam {
+                        name: String::new(),
+                        kind: ParamType::Bool,
+                        indexed: false,
+                    }],
+                    anonymous: false,
+                }],
+            );
+            context.artifact.abi.events.insert(
+                "Bar".into(),
+                vec![Event {
+                    name: "Bar".into(),
+                    inputs: vec![EventParam {
+                        name: String::new(),
+                        kind: ParamType::Address,
+                        indexed: false,
+                    }],
+                    anonymous: true,
+                }],
+            );
+            context
+        };
+
+        let foo_signature = expand_hash(context.artifact.abi.event("Foo").unwrap().signature());
+        let invalid_data = expand_invalid_data();
+
+        assert_quote!(expand_event_parse_log(&context), {
+            impl self::ethcontract::contract::ParseLog for Event {
+                fn parse_log(
+                    log: self::ethcontract::RawLog,
+                ) -> Result<Self, self::ethcontract::errors::ExecutionError> {
+                    let standard_event = log.topics
+                        .get(0)
+                        .copied()
+                        .map(|topic| match topic {
+                            #foo_signature => Ok(Event::Foo(
+                                log.clone().decode(
+                                    &Contract::artifact()
+                                        .abi
+                                        .event("Foo")
+                                        .expect("generated event decode")
+                                )?
+                            )),
+                            _ => #invalid_data,
+                        });
+
+                    if let Some(Ok(data)) = standard_event {
+                        return Ok(data);
+                    }
+
+                    if let Ok(data) = log.clone().decode(
+                        &Contract::artifact()
+                            .abi
+                            .event("Bar")
+                            .expect("generated event decode")
+                    ) {
+                        return Ok(Event::Bar(data));
+                    }
+
+                    #invalid_data
+                }
+            }
+        });
+    }
+
+    #[test]
+    #[rustfmt::skip]
+    fn expand_hash_value() {
+        assert_quote!(
+            expand_hash(
+                "000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f".parse().unwrap()
+            ),
+            {
+                self::ethcontract::H256([
+                    0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
+                    16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31
+                ])
+            },
+        );
+    }
+}

crates/ethers-derive/src/src/contract/methods.rs

@@ -0,0 +1,255 @@
+use crate::contract::{types, Context};
+use crate::util;
+use anyhow::{anyhow, Context as _, Result};
+use ethcontract_common::abi::{Function, Param};
+use ethcontract_common::abiext::FunctionExt;
+use ethcontract_common::hash::H32;
+use inflector::Inflector;
+use proc_macro2::{Literal, TokenStream};
+use quote::quote;
+use syn::Ident;
+
+pub(crate) fn expand(cx: &Context) -> Result<TokenStream> {
+    let functions = expand_functions(cx)?;
+    let fallback = expand_fallback(cx);
+
+    Ok(quote! {
+        #functions
+        #fallback
+    })
+}
+
+/// Expands a context into a method struct containing all the generated bindings
+/// to the Solidity contract methods.
+fn expand_functions(cx: &Context) -> Result<TokenStream> {
+    let mut aliases = cx.method_aliases.clone();
+    let functions = cx
+        .artifact
+        .abi
+        .functions()
+        .map(|function| {
+            let signature = function.abi_signature();
+            expand_function(&cx, function, aliases.remove(&signature))
+                .with_context(|| format!("error expanding function '{}'", signature))
+        })
+        .collect::<Result<Vec<_>>>()?;
+    if let Some(unused) = aliases.keys().next() {
+        return Err(anyhow!(
+            "a manual method alias for '{}' was specified but this method does not exist",
+            unused,
+        ));
+    }
+
+    let methods_attrs = quote! { #[derive(Clone)] };
+    let methods_struct = quote! {
+        struct Methods {
+            instance: self::ethcontract::dyns::DynInstance,
+        }
+    };
+
+    if functions.is_empty() {
+        // NOTE: The methods struct is still needed when there are no functions
+        //   as it contains the the runtime instance. The code is setup this way
+        //   so that the contract can implement `Deref` targetting the methods
+        //   struct and, therefore, call the methods directly.
+        return Ok(quote! {
+            #methods_attrs
+            #methods_struct
+        });
+    }
+
+    Ok(quote! {
+        impl Contract {
+            /// Retrives a reference to type containing all the generated
+            /// contract methods. This can be used for methods where the name
+            /// would collide with a common method (like `at` or `deployed`).
+            pub fn methods(&self) -> &Methods {
+                &self.methods
+            }
+        }
+
+        /// Type containing all contract methods for generated contract type.
+        #methods_attrs
+        pub #methods_struct
+
+        #[allow(clippy::too_many_arguments, clippy::type_complexity)]
+        impl Methods {
+            #( #functions )*
+        }
+
+        impl std::ops::Deref for Contract {
+            type Target = Methods;
+            fn deref(&self) -> &Self::Target {
+                &self.methods
+            }
+        }
+    })
+}
+
+fn expand_function(cx: &Context, function: &Function, alias: Option<Ident>) -> Result<TokenStream> {
+    let name = alias.unwrap_or_else(|| util::safe_ident(&function.name.to_snake_case()));
+    let signature = function.abi_signature();
+    let selector = expand_selector(function.selector());
+
+    let doc_str = cx
+        .artifact
+        .devdoc
+        .methods
+        .get(&signature)
+        .or_else(|| cx.artifact.userdoc.methods.get(&signature))
+        .and_then(|entry| entry.details.as_ref())
+        .map(String::as_str)
+        .unwrap_or("Generated by `ethcontract`");
+    let doc = util::expand_doc(doc_str);
+
+    let input = expand_inputs(&function.inputs)?;
+    let outputs = expand_fn_outputs(&function.outputs)?;
+    let (method, result_type_name) = if function.constant {
+        (quote! { view_method }, quote! { DynViewMethodBuilder })
+    } else {
+        (quote! { method }, quote! { DynMethodBuilder })
+    };
+    let result = quote! { self::ethcontract::dyns::#result_type_name<#outputs> };
+    let arg = expand_inputs_call_arg(&function.inputs);
+
+    Ok(quote! {
+        #doc
+        pub fn #name(&self #input) -> #result {
+            self.instance.#method(#selector, #arg)
+                .expect("generated call")
+        }
+    })
+}
+
+pub(crate) fn expand_inputs(inputs: &[Param]) -> Result<TokenStream> {
+    let params = inputs
+        .iter()
+        .enumerate()
+        .map(|(i, param)| {
+            let name = util::expand_input_name(i, &param.name);
+            let kind = types::expand(&param.kind)?;
+            Ok(quote! { #name: #kind })
+        })
+        .collect::<Result<Vec<_>>>()?;
+    Ok(quote! { #( , #params )* })
+}
+
+pub(crate) fn expand_inputs_call_arg(inputs: &[Param]) -> TokenStream {
+    let names = inputs
+        .iter()
+        .enumerate()
+        .map(|(i, param)| util::expand_input_name(i, &param.name));
+    quote! { ( #( #names ,)* ) }
+}
+
+fn expand_fn_outputs(outputs: &[Param]) -> Result<TokenStream> {
+    match outputs.len() {
+        0 => Ok(quote! { self::ethcontract::Void }),
+        1 => types::expand(&outputs[0].kind),
+        _ => {
+            let types = outputs
+                .iter()
+                .map(|param| types::expand(&param.kind))
+                .collect::<Result<Vec<_>>>()?;
+            Ok(quote! { (#( #types ),*) })
+        }
+    }
+}
+
+fn expand_selector(selector: H32) -> TokenStream {
+    let bytes = selector.iter().copied().map(Literal::u8_unsuffixed);
+    quote! { [#( #bytes ),*] }
+}
+
+/// Expands a context into fallback method when the contract implements one,
+/// and an empty token stream otherwise.
+fn expand_fallback(cx: &Context) -> TokenStream {
+    if cx.artifact.abi.fallback {
+        quote! {
+            impl Contract {
+                /// Returns a method builder to setup a call to a smart
+                /// contract's fallback function.
+                pub fn fallback<D>(&self, data: D) -> self::ethcontract::dyns::DynMethodBuilder<
+                    self::ethcontract::Void,
+                >
+                where
+                    D: Into<Vec<u8>>,
+                {
+                    self.raw_instance().fallback(data)
+                        .expect("generated fallback method")
+                }
+            }
+        }
+    } else {
+        quote! {}
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ethcontract_common::abi::ParamType;
+
+    #[test]
+    fn expand_inputs_empty() {
+        assert_quote!(expand_inputs(&[]).unwrap().to_string(), {},);
+    }
+
+    #[test]
+    fn expand_inputs_() {
+        assert_quote!(
+            expand_inputs(
+
+                &[
+                    Param {
+                        name: "a".to_string(),
+                        kind: ParamType::Bool,
+                    },
+                    Param {
+                        name: "b".to_string(),
+                        kind: ParamType::Address,
+                    },
+                ],
+            )
+            .unwrap(),
+            { , a: bool, b: self::ethcontract::Address },
+        );
+    }
+
+    #[test]
+    fn expand_fn_outputs_empty() {
+        assert_quote!(expand_fn_outputs(&[],).unwrap(), {
+            self::ethcontract::Void
+        });
+    }
+
+    #[test]
+    fn expand_fn_outputs_single() {
+        assert_quote!(
+            expand_fn_outputs(&[Param {
+                name: "a".to_string(),
+                kind: ParamType::Bool,
+            }])
+            .unwrap(),
+            { bool },
+        );
+    }
+
+    #[test]
+    fn expand_fn_outputs_muliple() {
+        assert_quote!(
+            expand_fn_outputs(&[
+                Param {
+                    name: "a".to_string(),
+                    kind: ParamType::Bool,
+                },
+                Param {
+                    name: "b".to_string(),
+                    kind: ParamType::Address,
+                },
+            ],)
+            .unwrap(),
+            { (bool, self::ethcontract::Address) },
+        );
+    }
+}

crates/ethers-derive/src/src/contract/types.rs

@@ -0,0 +1,48 @@
+use anyhow::{anyhow, Result};
+use ethcontract_common::abi::ParamType;
+use proc_macro2::{Literal, TokenStream};
+use quote::quote;
+
+pub(crate) fn expand(kind: &ParamType) -> Result<TokenStream> {
+    match kind {
+        ParamType::Address => Ok(quote! { self::ethcontract::Address }),
+        ParamType::Bytes => Ok(quote! { Vec<u8> }),
+        ParamType::Int(n) => match n / 8 {
+            1 => Ok(quote! { i8 }),
+            2 => Ok(quote! { i16 }),
+            3..=4 => Ok(quote! { i32 }),
+            5..=8 => Ok(quote! { i64 }),
+            9..=16 => Ok(quote! { i128 }),
+            17..=32 => Ok(quote! { self::ethcontract::I256 }),
+            _ => Err(anyhow!("unsupported solidity type int{}", n)),
+        },
+        ParamType::Uint(n) => match n / 8 {
+            1 => Ok(quote! { u8 }),
+            2 => Ok(quote! { u16 }),
+            3..=4 => Ok(quote! { u32 }),
+            5..=8 => Ok(quote! { u64 }),
+            9..=16 => Ok(quote! { u128 }),
+            17..=32 => Ok(quote! { self::ethcontract::U256 }),
+            _ => Err(anyhow!("unsupported solidity type uint{}", n)),
+        },
+        ParamType::Bool => Ok(quote! { bool }),
+        ParamType::String => Ok(quote! { String }),
+        ParamType::Array(t) => {
+            let inner = expand(t)?;
+            Ok(quote! { Vec<#inner> })
+        }
+        ParamType::FixedBytes(n) => {
+            // TODO(nlordell): what is the performance impact of returning large
+            //   `FixedBytes` and `FixedArray`s with `web3`?
+            let size = Literal::usize_unsuffixed(*n);
+            Ok(quote! { [u8; #size] })
+        }
+        ParamType::FixedArray(t, n) => {
+            // TODO(nlordell): see above
+            let inner = expand(t)?;
+            let size = Literal::usize_unsuffixed(*n);
+            Ok(quote! { [#inner; #size] })
+        }
+        ParamType::Tuple(_) => Err(anyhow!("ABIEncoderV2 is currently not supported")),
+    }
+}

crates/ethers-derive/src/src/lib.rs

@@ -0,0 +1,286 @@
+#![deny(missing_docs, unsafe_code)]
+
+//! Crate for generating type-safe bindings to Ethereum smart contracts. This
+//! crate is intended to be used either indirectly with the `ethcontract`
+//! crate's `contract` procedural macro or directly from a build script.
+
+#[cfg(test)]
+#[allow(missing_docs)]
+#[macro_use]
+#[path = "test/macros.rs"]
+mod test_macros;
+
+mod contract;
+mod rustfmt;
+mod source;
+mod util;
+
+pub use crate::source::Source;
+pub use crate::util::parse_address;
+use anyhow::Result;
+pub use ethcontract_common::Address;
+use proc_macro2::TokenStream;
+use std::collections::HashMap;
+use std::fs::File;
+use std::io::Write;
+use std::path::Path;
+
+/// Internal global arguments passed to the generators for each individual
+/// component that control expansion.
+pub(crate) struct Args {
+    /// The source of the truffle artifact JSON for the contract whose bindings
+    /// are being generated.
+    artifact_source: Source,
+    /// The runtime crate name to use.
+    runtime_crate_name: String,
+    /// The visibility modifier to use for the generated module and contract
+    /// re-export.
+    visibility_modifier: Option<String>,
+    /// Override the contract module name that contains the generated code.
+    contract_mod_override: Option<String>,
+    /// Override the contract name to use for the generated type.
+    contract_name_override: Option<String>,
+    /// Manually specified deployed contract addresses.
+    deployments: HashMap<u32, Address>,
+    /// Manually specified contract method aliases.
+    method_aliases: HashMap<String, String>,
+    /// Derives added to event structs and enums.
+    event_derives: Vec<String>,
+}
+
+impl Args {
+    /// Creates a new builder given the path to a contract's truffle artifact
+    /// JSON file.
+    pub fn new(source: Source) -> Self {
+        Args {
+            artifact_source: source,
+            runtime_crate_name: "ethcontract".to_owned(),
+            visibility_modifier: None,
+            contract_mod_override: None,
+            contract_name_override: None,
+            deployments: HashMap::new(),
+            method_aliases: HashMap::new(),
+            event_derives: Vec::new(),
+        }
+    }
+}
+
+/// Internal output options for controlling how the generated code gets
+/// serialized to file.
+struct SerializationOptions {
+    /// Format the code using a locally installed copy of `rustfmt`.
+    rustfmt: bool,
+}
+
+impl Default for SerializationOptions {
+    fn default() -> Self {
+        SerializationOptions { rustfmt: true }
+    }
+}
+
+/// Builder for generating contract code. Note that no code is generated until
+/// the builder is finalized with `generate` or `output`.
+pub struct Builder {
+    /// The contract binding generation args.
+    args: Args,
+    /// The serialization options.
+    options: SerializationOptions,
+}
+
+impl Builder {
+    /// Creates a new builder given the path to a contract's truffle artifact
+    /// JSON file.
+    pub fn new<P>(artifact_path: P) -> Self
+    where
+        P: AsRef<Path>,
+    {
+        Builder::with_source(Source::local(artifact_path))
+    }
+
+    /// Creates a new builder from a source URL.
+    pub fn from_source_url<S>(source_url: S) -> Result<Self>
+    where
+        S: AsRef<str>,
+    {
+        let source = Source::parse(source_url)?;
+        Ok(Builder::with_source(source))
+    }
+
+    /// Creates a new builder with the given artifact JSON source.
+    pub fn with_source(source: Source) -> Self {
+        Builder {
+            args: Args::new(source),
+            options: SerializationOptions::default(),
+        }
+    }
+
+    /// Sets the crate name for the runtime crate. This setting is usually only
+    /// needed if the crate was renamed in the Cargo manifest.
+    pub fn with_runtime_crate_name<S>(mut self, name: S) -> Self
+    where
+        S: Into<String>,
+    {
+        self.args.runtime_crate_name = name.into();
+        self
+    }
+
+    /// Sets an optional visibility modifier for the generated module and
+    /// contract re-export.
+    pub fn with_visibility_modifier<S>(mut self, vis: Option<S>) -> Self
+    where
+        S: Into<String>,
+    {
+        self.args.visibility_modifier = vis.map(S::into);
+        self
+    }
+
+    /// Sets the optional contract module name override.
+    pub fn with_contract_mod_override<S>(mut self, name: Option<S>) -> Self
+    where
+        S: Into<String>,
+    {
+        self.args.contract_mod_override = name.map(S::into);
+        self
+    }
+
+    /// Sets the optional contract name override. This setting is needed when
+    /// using a artifact JSON source that does not provide a contract name such
+    /// as Etherscan.
+    pub fn with_contract_name_override<S>(mut self, name: Option<S>) -> Self
+    where
+        S: Into<String>,
+    {
+        self.args.contract_name_override = name.map(S::into);
+        self
+    }
+
+    /// Manually adds specifies the deployed address of a contract for a given
+    /// network. Note that manually specified deployments take precedence over
+    /// deployments in the Truffle artifact (in the `networks` property of the
+    /// artifact).
+    ///
+    /// This is useful for integration test scenarios where the address of a
+    /// contract on the test node is deterministic (for example using
+    /// `ganache-cli -d`) but the contract address is not part of the Truffle
+    /// artifact; or to override a deployment included in a Truffle artifact.
+    pub fn add_deployment(mut self, network_id: u32, address: Address) -> Self {
+        self.args.deployments.insert(network_id, address);
+        self
+    }
+
+    /// Manually adds specifies the deployed address as a string of a contract
+    /// for a given network. See `Builder::add_deployment` for more information.
+    ///
+    /// # Panics
+    ///
+    /// This method panics if the specified address string is invalid. See
+    /// `parse_address` for more information on the address string format.
+    pub fn add_deployment_str<S>(self, network_id: u32, address: S) -> Self
+    where
+        S: AsRef<str>,
+    {
+        self.add_deployment(
+            network_id,
+            parse_address(address).expect("failed to parse address"),
+        )
+    }
+
+    /// Manually adds a solidity method alias to specify what the method name
+    /// will be in Rust. For solidity methods without an alias, the snake cased
+    /// method name will be used.
+    pub fn add_method_alias<S1, S2>(mut self, signature: S1, alias: S2) -> Self
+    where
+        S1: Into<String>,
+        S2: Into<String>,
+    {
+        self.args
+            .method_aliases
+            .insert(signature.into(), alias.into());
+        self
+    }
+
+    /// Specify whether or not to format the code using a locally installed copy
+    /// of `rustfmt`.
+    ///
+    /// Note that in case `rustfmt` does not exist or produces an error, the
+    /// unformatted code will be used.
+    pub fn with_rustfmt(mut self, rustfmt: bool) -> Self {
+        self.options.rustfmt = rustfmt;
+        self
+    }
+
+    /// Add a custom derive to the derives for event structs and enums.
+    ///
+    /// This makes it possible to for example derive serde::Serialize and
+    /// serde::Deserialize for events.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use ethcontract_generate::Builder;
+    /// let builder = Builder::new("path")
+    ///     .add_event_derive("serde::Serialize")
+    ///     .add_event_derive("serde::Deserialize");
+    /// ```
+    pub fn add_event_derive<S>(mut self, derive: S) -> Self
+    where
+        S: Into<String>,
+    {
+        self.args.event_derives.push(derive.into());
+        self
+    }
+
+    /// Generates the contract bindings.
+    pub fn generate(self) -> Result<ContractBindings> {
+        let tokens = contract::expand(self.args)?;
+        Ok(ContractBindings {
+            tokens,
+            options: self.options,
+        })
+    }
+}
+
+/// Type-safe contract bindings generated by a `Builder`. This type can be
+/// either written to file or into a token stream for use in a procedural macro.
+pub struct ContractBindings {
+    /// The TokenStream representing the contract bindings.
+    tokens: TokenStream,
+    /// The output options used for serialization.
+    options: SerializationOptions,
+}
+
+impl ContractBindings {
+    /// Writes the bindings to a given `Write`.
+    pub fn write<W>(&self, mut w: W) -> Result<()>
+    where
+        W: Write,
+    {
+        let source = {
+            let raw = self.tokens.to_string();
+
+            if self.options.rustfmt {
+                rustfmt::format(&raw).unwrap_or(raw)
+            } else {
+                raw
+            }
+        };
+
+        w.write_all(source.as_bytes())?;
+        Ok(())
+    }
+
+    /// Writes the bindings to the specified file.
+    pub fn write_to_file<P>(&self, path: P) -> Result<()>
+    where
+        P: AsRef<Path>,
+    {
+        let file = File::create(path)?;
+        self.write(file)
+    }
+
+    /// Converts the bindings into its underlying token stream. This allows it
+    /// to be used within a procedural macro.
+    pub fn into_tokens(self) -> TokenStream {
+        self.tokens
+    }
+}

crates/ethers-derive/src/src/rustfmt.rs

@@ -0,0 +1,36 @@
+//! This module implements basic `rustfmt` code formatting.
+
+use anyhow::{anyhow, Result};
+use std::io::Write;
+use std::process::{Command, Stdio};
+
+/// Format the raw input source string and return formatted output.
+pub fn format<S>(source: S) -> Result<String>
+where
+    S: AsRef<str>,
+{
+    let mut rustfmt = Command::new("rustfmt")
+        .stdin(Stdio::piped())
+        .stdout(Stdio::piped())
+        .spawn()?;
+
+    {
+        let stdin = rustfmt
+            .stdin
+            .as_mut()
+            .ok_or_else(|| anyhow!("stdin was not created for `rustfmt` child process"))?;
+        stdin.write_all(source.as_ref().as_bytes())?;
+    }
+
+    let output = rustfmt.wait_with_output()?;
+    if !output.status.success() {
+        return Err(anyhow!(
+            "`rustfmt` exited with code {}:\n{}",
+            output.status,
+            String::from_utf8_lossy(&output.stderr),
+        ));
+    }
+
+    let stdout = String::from_utf8(output.stdout)?;
+    Ok(stdout)
+}

crates/ethers-derive/src/src/source.rs

@@ -0,0 +1,260 @@
+//! Module implements reading of contract artifacts from various sources.
+
+use crate::util;
+use anyhow::{anyhow, Context, Error, Result};
+use ethcontract_common::Address;
+use std::borrow::Cow;
+use std::env;
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::str::FromStr;
+use url::Url;
+
+/// A source of a Truffle artifact JSON.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub enum Source {
+    /// A Truffle artifact or ABI located on the local file system.
+    Local(PathBuf),
+    /// A truffle artifact or ABI to be retrieved over HTTP(S).
+    Http(Url),
+    /// An address of a mainnet contract that has been verified on Etherscan.io.
+    Etherscan(Address),
+    /// The package identifier of an npm package with a path to a Truffle
+    /// artifact or ABI to be retrieved from `unpkg.io`.
+    Npm(String),
+}
+
+impl Source {
+    /// Parses an artifact source from a string.
+    ///
+    /// Contract artifacts can be retrieved from the local filesystem or online
+    /// from `etherscan.io`, this method parses artifact source URLs and accepts
+    /// the following:
+    /// - `relative/path/to/Contract.json`: a relative path to a truffle
+    ///   artifact JSON file. This relative path is rooted in the current
+    ///   working directory. To specify the root for relative paths, use
+    ///   `Source::with_root`.
+    /// - `/absolute/path/to/Contract.json` or
+    ///   `file:///absolute/path/to/Contract.json`: an absolute path or file URL
+    ///   to a truffle artifact JSON file.
+    /// - `http(s)://...` an HTTP url to a contract ABI or Truffle artifact.
+    /// - `etherscan:0xXX..XX` or `https://etherscan.io/address/0xXX..XX`: a
+    ///   address or URL of a verified contract on Etherscan.
+    /// - `npm:@org/package@1.0.0/path/to/contract.json` an npmjs package with
+    ///   an optional version and path (defaulting to the latest version and
+    ///   `index.js`). The contract artifact or ABI will be retrieved through
+    ///   `unpkg.io`.
+    pub fn parse<S>(source: S) -> Result<Self>
+    where
+        S: AsRef<str>,
+    {
+        let root = env::current_dir()?.canonicalize()?;
+        Source::with_root(root, source)
+    }
+
+    /// Parses an artifact source from a string and a specified root directory
+    /// for resolving relative paths. See `Source::with_root` for more details
+    /// on supported source strings.
+    pub fn with_root<P, S>(root: P, source: S) -> Result<Self>
+    where
+        P: AsRef<Path>,
+        S: AsRef<str>,
+    {
+        let base = Url::from_directory_path(root)
+            .map_err(|_| anyhow!("root path '{}' is not absolute"))?;
+        let url = base.join(source.as_ref())?;
+
+        match url.scheme() {
+            "file" => Ok(Source::local(url.path())),
+            "http" | "https" => match url.host_str() {
+                Some("etherscan.io") => Source::etherscan(
+                    url.path()
+                        .rsplit('/')
+                        .next()
+                        .ok_or_else(|| anyhow!("HTTP URL does not have a path"))?,
+                ),
+                _ => Ok(Source::Http(url)),
+            },
+            "etherscan" => Source::etherscan(url.path()),
+            "npm" => Ok(Source::npm(url.path())),
+            _ => Err(anyhow!("unsupported URL '{}'", url)),
+        }
+    }
+
+    /// Creates a local filesystem source from a path string.
+    pub fn local<P>(path: P) -> Self
+    where
+        P: AsRef<Path>,
+    {
+        Source::Local(path.as_ref().into())
+    }
+
+    /// Creates an HTTP source from a URL.
+    pub fn http<S>(url: S) -> Result<Self>
+    where
+        S: AsRef<str>,
+    {
+        Ok(Source::Http(Url::parse(url.as_ref())?))
+    }
+
+    /// Creates an Etherscan source from an address string.
+    pub fn etherscan<S>(address: S) -> Result<Self>
+    where
+        S: AsRef<str>,
+    {
+        let address =
+            util::parse_address(address).context("failed to parse address for Etherscan source")?;
+        Ok(Source::Etherscan(address))
+    }
+
+    /// Creates an Etherscan source from an address string.
+    pub fn npm<S>(package_path: S) -> Self
+    where
+        S: Into<String>,
+    {
+        Source::Npm(package_path.into())
+    }
+
+    /// Retrieves the source JSON of the artifact this will either read the JSON
+    /// from the file system or retrieve a contract ABI from the network
+    /// dependending on the source type.
+    pub fn artifact_json(&self) -> Result<String> {
+        match self {
+            Source::Local(path) => get_local_contract(path),
+            Source::Http(url) => get_http_contract(url),
+            Source::Etherscan(address) => get_etherscan_contract(*address),
+            Source::Npm(package) => get_npm_contract(package),
+        }
+    }
+}
+
+impl FromStr for Source {
+    type Err = Error;
+
+    fn from_str(s: &str) -> Result<Self> {
+        Source::parse(s)
+    }
+}
+
+/// Reads a Truffle artifact JSON file from the local filesystem.
+fn get_local_contract(path: &Path) -> Result<String> {
+    let path = if path.is_relative() {
+        let absolute_path = path.canonicalize().with_context(|| {
+            format!(
+                "unable to canonicalize file from working dir {} with path {}",
+                env::current_dir()
+                    .map(|cwd| cwd.display().to_string())
+                    .unwrap_or_else(|err| format!("??? ({})", err)),
+                path.display(),
+            )
+        })?;
+        Cow::Owned(absolute_path)
+    } else {
+        Cow::Borrowed(path)
+    };
+
+    let json = fs::read_to_string(path).context("failed to read artifact JSON file")?;
+    Ok(abi_or_artifact(json))
+}
+
+/// Retrieves a Truffle artifact or ABI from an HTTP URL.
+fn get_http_contract(url: &Url) -> Result<String> {
+    let json = util::http_get(url.as_str())
+        .with_context(|| format!("failed to retrieve JSON from {}", url))?;
+    Ok(abi_or_artifact(json))
+}
+
+/// Retrieves a contract ABI from the Etherscan HTTP API and wraps it in an
+/// artifact JSON for compatibility with the code generation facilities.
+fn get_etherscan_contract(address: Address) -> Result<String> {
+    // NOTE: We do not retrieve the bytecode since deploying contracts with the
+    //   same bytecode is unreliable as the libraries have already linked and
+    //   probably don't reference anything when deploying on other networks.
+
+    let api_key = env::var("ETHERSCAN_API_KEY")
+        .map(|key| format!("&apikey={}", key))
+        .unwrap_or_default();
+
+    let abi_url = format!(
+        "http://api.etherscan.io/api\
+         ?module=contract&action=getabi&address={:?}&format=raw{}",
+        address, api_key,
+    );
+    let abi = util::http_get(&abi_url).context("failed to retrieve ABI from Etherscan.io")?;
+
+    // NOTE: Wrap the retrieved ABI in an empty contract, this is because
+    //   currently, the code generation infrastructure depends on having an
+    //   `Artifact` instance.
+    let json = format!(
+        r#"{{"abi":{},"networks":{{"1":{{"address":"{:?}"}}}}}}"#,
+        abi, address,
+    );
+
+    Ok(json)
+}
+
+/// Retrieves a Truffle artifact or ABI from an npm package through `unpkg.io`.
+fn get_npm_contract(package: &str) -> Result<String> {
+    let unpkg_url = format!("https://unpkg.io/{}", package);
+    let json = util::http_get(&unpkg_url)
+        .with_context(|| format!("failed to retrieve JSON from for npm package {}", package))?;
+
+    Ok(abi_or_artifact(json))
+}
+
+/// A best-effort coersion of an ABI or Truffle artifact JSON document into a
+/// Truffle artifact JSON document.
+///
+/// This method uses the fact that ABIs are arrays and Truffle artifacts are
+/// objects to guess at what type of document this is. Note that no parsing or
+/// validation is done at this point as the document gets parsed and validated
+/// at generation time.
+///
+/// This needs to be done as currently the contract generation infrastructure
+/// depends on having a Truffle artifact.
+fn abi_or_artifact(json: String) -> String {
+    if json.trim().starts_with('[') {
+        format!(r#"{{"abi":{}}}"#, json.trim())
+    } else {
+        json
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn parse_source() {
+        let root = "/rooted";
+        for (url, expected) in &[
+            (
+                "relative/Contract.json",
+                Source::local("/rooted/relative/Contract.json"),
+            ),
+            (
+                "/absolute/Contract.json",
+                Source::local("/absolute/Contract.json"),
+            ),
+            (
+                "https://my.domain.eth/path/to/Contract.json",
+                Source::http("https://my.domain.eth/path/to/Contract.json").unwrap(),
+            ),
+            (
+                "etherscan:0x0001020304050607080910111213141516171819",
+                Source::etherscan("0x0001020304050607080910111213141516171819").unwrap(),
+            ),
+            (
+                "https://etherscan.io/address/0x0001020304050607080910111213141516171819",
+                Source::etherscan("0x0001020304050607080910111213141516171819").unwrap(),
+            ),
+            (
+                "npm:@openzeppelin/contracts@2.5.0/build/contracts/IERC20.json",
+                Source::npm("@openzeppelin/contracts@2.5.0/build/contracts/IERC20.json"),
+            ),
+        ] {
+            let source = Source::with_root(root, url).unwrap();
+            assert_eq!(source, *expected);
+        }
+    }
+}

crates/ethers-derive/src/src/test/macros.rs

@@ -0,0 +1,10 @@
+/// Asserts the result of an expansion matches source output.
+///
+/// # Panics
+///
+/// If the expanded source does not match the quoted source.
+macro_rules! assert_quote {
+    ($ex:expr, { $($t:tt)* } $(,)?) => {
+        assert_eq!($ex.to_string(), quote::quote! { $($t)* }.to_string())
+    };
+}

crates/ethers-derive/src/src/util.rs

@@ -0,0 +1,117 @@
+use anyhow::{anyhow, Result};
+use curl::easy::Easy;
+use ethcontract_common::Address;
+use inflector::Inflector;
+use proc_macro2::{Ident, Literal, Span, TokenStream};
+use quote::quote;
+use syn::Ident as SynIdent;
+
+/// Expands a identifier string into an token.
+pub fn ident(name: &str) -> Ident {
+    Ident::new(name, Span::call_site())
+}
+
+/// Expands an identifier string into a token and appending `_` if the
+/// identifier is for a reserved keyword.
+///
+/// Parsing keywords like `self` can fail, in this case we add an underscore.
+pub fn safe_ident(name: &str) -> Ident {
+    syn::parse_str::<SynIdent>(name).unwrap_or_else(|_| ident(&format!("{}_", name)))
+}
+
+/// Expands a positional identifier string that may be empty.
+///
+/// Note that this expands the parameter name with `safe_ident`, meaning that
+/// identifiers that are reserved keywords get `_` appended to them.
+pub fn expand_input_name(index: usize, name: &str) -> TokenStream {
+    let name_str = match name {
+        "" => format!("p{}", index),
+        n => n.to_snake_case(),
+    };
+    let name = safe_ident(&name_str);
+
+    quote! { #name }
+}
+
+/// Expands a doc string into an attribute token stream.
+pub fn expand_doc(s: &str) -> TokenStream {
+    let doc = Literal::string(s);
+    quote! {
+        #[doc = #doc]
+    }
+}
+
+/// Parses the given address string
+pub fn parse_address<S>(address_str: S) -> Result<Address>
+where
+    S: AsRef<str>,
+{
+    let address_str = address_str.as_ref();
+    if !address_str.starts_with("0x") {
+        return Err(anyhow!("address must start with '0x'"));
+    }
+    Ok(address_str[2..].parse()?)
+}
+
+/// Perform an HTTP GET request and return the contents of the response.
+pub fn http_get(url: &str) -> Result<String> {
+    let mut buffer = Vec::new();
+    let mut handle = Easy::new();
+    handle.url(url)?;
+    {
+        let mut transfer = handle.transfer();
+        transfer.write_function(|data| {
+            buffer.extend_from_slice(data);
+            Ok(data.len())
+        })?;
+        transfer.perform()?;
+    }
+
+    let buffer = String::from_utf8(buffer)?;
+    Ok(buffer)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn input_name_to_ident_empty() {
+        assert_quote!(expand_input_name(0, ""), { p0 });
+    }
+
+    #[test]
+    fn input_name_to_ident_keyword() {
+        assert_quote!(expand_input_name(0, "self"), { self_ });
+    }
+
+    #[test]
+    fn input_name_to_ident_snake_case() {
+        assert_quote!(expand_input_name(0, "CamelCase1"), { camel_case_1 });
+    }
+
+    #[test]
+    fn parse_address_missing_prefix() {
+        if parse_address("0000000000000000000000000000000000000000").is_ok() {
+            panic!("parsing address not starting with 0x should fail");
+        }
+    }
+
+    #[test]
+    fn parse_address_address_too_short() {
+        if parse_address("0x00000000000000").is_ok() {
+            panic!("parsing address not starting with 0x should fail");
+        }
+    }
+
+    #[test]
+    fn parse_address_ok() {
+        let expected = Address::from([
+            0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
+        ]);
+        assert_eq!(
+            parse_address("0x000102030405060708090a0b0c0d0e0f10111213").unwrap(),
+            expected
+        );
+    }
+}

crates/ethers-providers/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ethers-providers"
+version = "0.1.0"
+authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

crates/ethers-providers/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}

crates/ethers-signers/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ethers-signers"
+version = "0.1.0"
+authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

crates/ethers-signers/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}

crates/ethers-types/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "ethers-types"
+version = "0.1.0"
+authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+ethereum-types = { version = "0.9.2", default-features = false, features = ["serialize"] }
+serde = { version = "1.0.110", default-features = false, features = ["derive"] }
+rlp = { version = "0.4.5", default-features = false }
+rustc-hex = { version = "2.1.0", default-features = false }
+thiserror = { version = "1.0.19", default-features = false }
+
+# crypto
+secp256k1 = { version = "0.17.2", default-features = false, features = ["std", "recovery", "rand"] }
+rand = { version = "0.5.1", default-features = false } # this should be the same rand crate version as the one in secp
+zeroize = { version = "1.1.0", default-features = false }

crates/ethers-utils/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "ethers-utils"
+version = "0.1.0"
+authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

crates/ethers-utils/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}

crates/ethers/Cargo.toml

@@ -0,0 +1,11 @@
+[package]
+name = "ethers"
+version = "0.1.0"
+authors = ["Georgios Konstantopoulos <me@gakonst.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+
+# TODO: Make this have features for each available module