Struct scanner

list-structs.go

package main

import (
    "flag"
    "fmt"
    "go/ast"
    "go/parser"
    "go/token"
    "io"
    "os"
)

var file string
var help bool

func init() {
    flag.StringVar(&file, "i", "", "input file")
    flag.BoolVar(&help, "h", false, "show this help")
    flag.Parse()

    if help {
        flag.Usage()
        os.Exit(0)
    }
}

type Summary map[string][]string

func newSummary() Summary {
    return Summary{}
}

func (s Summary) Add(key, value string) {
    if _, ok := s[key]; ok {
        s[key] = append(s[key], value)
    } else {
        s[key] = []string{value}
    }
}

func (s Summary) Write(w io.Writer) {
    for k, names := range s {
        fmt.Fprintf(w, "%s:\n", k)
        for _, name := range names {
            fmt.Fprintf(w, "\t%s\n", name)
        }
    }
}

func main() {
    fset := token.NewFileSet()
    f, err := parser.ParseFile(fset, file, nil, 0)
    if err != nil {
        panic(err)
    }
    fmt.Println("~~ Hi!! ~~")

    summary := newSummary()

    for _, decl := range f.Decls {
        dec, ok := decl.(*ast.GenDecl)
        if !ok || dec.Tok != token.TYPE {
            continue
        }

        for _, spec := range dec.Specs {
            ty, ok := spec.(*ast.TypeSpec)
            if !ok {
                continue
            }

            structName := ty.Name.Name

            st, ok := ty.Type.(*ast.StructType)
            if !ok {
                continue
            }

            for _, field := range st.Fields.List {
                for _, name := range field.Names {
                    summary.Add(structName, name.Name)
                }
            }
        }
    }

    summary.Write(os.Stdout)
}