go__parsing_demo/02-basic_tree_walk/parse.go

package main

import (
	"fmt"
	"go/ast"
	"go/token"
)

func parseFile(f *ast.File) {
	loc := f.Name.String()
	for _, d := range f.Decls {
		switch d := d.(type) {
		case *ast.GenDecl:
			parseGenDecl(loc, d)
		case *ast.FuncDecl:
			parseFuncDecl(loc, d)
		default:
			fmt.Printf("Unknown decl type in %s: %T\n", loc, d)
		}
	}
}

// type specification: "type [=] <typ>"
func parseTypeSpec(loc string, s *ast.TypeSpec) {
	// type foo bool: .Name + .Type / .Assign = NoPos (== 0)
	// type foo = bool: .Name + .Type / .Assign = <pos>
	name := s.Name.String()
	if s.Assign == token.NoPos {
		fmt.Printf("%s/Defined %s: ", loc, name)
	} else {
		fmt.Printf("%s/Aliased %s: ", loc, name)
	}
	parseTypeExpr(loc, s.Type, true)
}