go-sigparser

The go-sigparser is a Go package that helps parse Ethereum function signatures. This parser uses the Solidity grammar rules.

However, it doesn't need argument names or the returns and function keywords to parse signatures. So, you can use it for both complete Solidity signatures and shorter versions like bar(uint256,bytes32).

Tuples are represented as a list of parameters, e.g. (uint256,bytes32). The list can be optionally prefixed with tuple keyword, e.g. tuple(uint256,bytes32).

The go-sigparser supports many different signature formats. Here are a few examples:

• getPrice(string)
• getPrice(string)((uint256,unit256))
• function getPrice(string calldata symbol) external view returns (tuple(uint256 price, uint256 timestamp) result)
• constructor(string symbol, string name)
• receive() external payable
• fallback (bytes calldata input) external payable returns (bytes memory output)
• event PriceUpdated(string indexed symbol, uint256 price)
• error PriceExpired(string symbol, uint256 timestamp)

Installation

You can install the go-sigparser package with this command:

go get github.com/ethereum/go-sigparser

Usage

Parsing Signature

package main

import (
	"fmt"

	"github.com/defiweb/go-sigparser"
)

func main() {
	sig, err := sigparser.ParseSignature("function getPrices(string[] calldata symbols) external view returns ((uint256 price, uint256 timestamp)[] result)")
	if err != nil {
		panic(err)
	}

	fmt.Println(sig.Kind)                     // function
	fmt.Println(sig.Name)                     // getPrice
	fmt.Println(sig.Inputs[0].Name)           // symbol
	fmt.Println(sig.Inputs[0].Type)           // string
	fmt.Println(sig.Inputs[0].Arrays)         // [-1] (-1 means that the array is unbounded)
	fmt.Println(sig.Inputs[0].DataLocation)   // calldata
	fmt.Println(sig.Modifiers)                // [external, view]
	fmt.Println(sig.Outputs[0].Name)          // result
	fmt.Println(sig.Outputs[0].Arrays)        // [-1] 
	fmt.Println(sig.Outputs[0].Tuple[0].Name) // price
	fmt.Println(sig.Outputs[0].Tuple[0].Type) // uint256
	fmt.Println(sig.Outputs[0].Tuple[1].Name) // timestamp
	fmt.Println(sig.Outputs[0].Tuple[1].Type) // uint256
}

Parsing Parameter

package main

import (
	"fmt"

	"github.com/defiweb/go-sigparser"
)

func main() {
	param, err := sigparser.ParseParameter("(uint256 price, uint256 timestamp)")
	if err != nil {
		panic(err)
	}

	fmt.Println(param.Tuple[0].Name) // price
	fmt.Println(param.Tuple[0].Type) // uint256
	fmt.Println(param.Tuple[1].Name) // timestamp
	fmt.Println(param.Tuple[1].Type) // uint256
}

Parsing Struct

You can also parse structs with go-sigparser. When you parse a struct, you get a tuple where the struct name is the parameter name, and the struct fields are the tuple elements. Here's an example:

package main

import (
	"fmt"

	"github.com/defiweb/go-sigparser"
)

func main() {
	param, err := sigparser.ParseStruct("struct name { uint256 price; uint256 timestamp; }")
	if err != nil {
		panic(err)
	}

	fmt.Println(param.Name)          // name
	fmt.Println(param.Tuple[0].Name) // price
	fmt.Println(param.Tuple[0].Type) // uint256
	fmt.Println(param.Tuple[1].Name) // timestamp
	fmt.Println(param.Tuple[1].Type) // uint256
}

Documentation

For more information about the go-sigparser package, visit https://pkg.go.dev/github.com/defiweb/go-sigparser.