README.md

Go Parser

The go-parser package is a small wrapper around the parser and ast packages.

Installation

To install this package, run:

go get github.com/zpatrick/go-parser

Motivation

If you've ever tried to implement code generation in Go, you're probably familiar with the parser and ast packages. These packages analyze and parse Go source files. The main problems I have with these packages are:

• They aren't very intuitive
• The amount of type assertions required to use them causes code to look cluttered and confusing

This package is meant to fix both of those issues. For example, the following two snippets of code perform the same function:

Using go-parser

    goFile, err := parser.ParseFile("user.go")
    if err != nil {
        log.Fatal(err)
    }

    for _, goStruct := range goFile.Structs {
        for _, goField := range goStruct.Fields {
            log.Println(goField.Name, goField.Type, goField.Tag)
        }
    }

Using ast and parser

    src, err := ioutil.ReadFile("user.go")
    if err != nil {
        log.Fatal(err)
    }

    file, err := parser.ParseFile(token.NewFileSet(), path, nil, 0)
    if err != nil {
        log.Fatal(err)
    }

    for _, d := range file.Decls {
        if typeDecl, ok := d.(*ast.GenDecl); ok {
            for _, s := range typeDecl.Specs {
                if typeSpec, ok := s.(*ast.TypeSpec); ok {
                    if structDecl, ok := typeSpec.Type.(*ast.StructType); ok {
                        for _, field := range structDecl.Fields.List {
                            for _, name := range field.Names {
                                name := name.String()
                                _type := string(src[field.Type.Pos()-1 : field.Type.End()-1])
                                tag := ""
                                if field.Tag != nil{
                                    tag = field.Tag.Value
                                }
                                
                                fmt.Printf(name, _type, tag)
                            }
                        }
                    }
                }
            }
        }
    }

Disclaimer & Contributing

I have been adding coverage on an as-needed basis. As such, this package is very much incomplete relative to the amount of coverage available in the ast and parser packages. However, merge requests are strongly encouraged! I've added a lot of comments to the parsing code to hopefully make it easier to read and contribute to.

License

This work is published under the MIT license.

Please see the LICENSE file for details.