go-vimlparser walk

output

node = (*ast.File) &{Start:sample.vim:1:1 Body:[0xc420001200 0xc420001380]}
  node = (*ast.Function) &{Func:sample.vim:1:1 ExArg:{Forceit:true AddrCount:0 Line1:0 Line2:0 Flags:0 DoEcmdCmd: DoEcmdLnum:0 Append:0 Usefilter:false Amount:0 Regname:0 ForceBin:0 ReadEdit:0 ForceFf: ForceEnc: BadChar: Linepos:sample.vim:1:1 Cmdpos:sample.vim:1:1 Argpos:sample.vim:1:11 Cmd:0xc42005e500 Modifiers:[] Range:[] Argopt:map[] Argcmd:map[]} Body:[0xc4200e3540] Name:0xc42005e640 Params:[] Attr:{Range:false Abort:false Dict:false Closure:false} EndFunction:0xc4200e3680}
    node = (*ast.Ident) &{NamePos:sample.vim:1:11 Name:s:f}
      node = (<nil>) <nil>
    node = (*ast.ExCall) &{ExCall:sample.vim:2:3 ExArg:{Forceit:false AddrCount:0 Line1:0 Line2:0 Flags:0 DoEcmdCmd: DoEcmdLnum:0 Append:0 Usefilter:false Amount:0 Regname:0 ForceBin:0 ReadEdit:0 ForceFf: ForceEnc: BadChar: Linepos:sample.vim:2:3 Cmdpos:sample.vim:2:3 Argpos:sample.vim:2:8 Cmd:0xc42005e540 Modifiers:[] Range:[] Argopt:map[] Argcmd:map[]} FuncCall:0xc42008d630}
      node = (*ast.CallExpr) &{Fun:0xc42005e580 Lparen:sample.vim:2:11 Args:[0xc42008d5e0]}
        node = (*ast.Ident) &{NamePos:sample.vim:2:8 Name:s:g}
          node = (<nil>) <nil>
        node = (*ast.BinaryExpr) &{Left:0xc42005e5c0 OpPos:sample.vim:2:14 Op:+ Right:0xc42005e600}
          node = (*ast.BasicLit) &{ValuePos:sample.vim:2:12 Kind:<NUMBER> Value:1}
            node = (<nil>) <nil>
          node = (*ast.BasicLit) &{ValuePos:sample.vim:2:16 Kind:<NUMBER> Value:1}
            node = (<nil>) <nil>
          node = (<nil>) <nil>
        node = (<nil>) <nil>
      node = (<nil>) <nil>
    node = (*ast.EndFunction) &{EndFunc:sample.vim:3:1 ExArg:{Forceit:false AddrCount:0 Line1:0 Line2:0 Flags:0 DoEcmdCmd: DoEcmdLnum:0 Append:0 Usefilter:false Amount:0 Regname:0 ForceBin:0 ReadEdit:0 ForceFf: ForceEnc: BadChar: Linepos:sample.vim:3:1 Cmdpos:sample.vim:3:1 Argpos:sample.vim:3:12 Cmd:0xc42005e680 Modifiers:[] Range:[] Argopt:map[] Argcmd:map[]}}
      node = (<nil>) <nil>
    node = (<nil>) <nil>
  node = (*ast.Function) &{Func:sample.vim:5:1 ExArg:{Forceit:true AddrCount:0 Line1:0 Line2:0 Flags:0 DoEcmdCmd: DoEcmdLnum:0 Append:0 Usefilter:false Amount:0 Regname:0 ForceBin:0 ReadEdit:0 ForceFf: ForceEnc: BadChar: Linepos:sample.vim:5:1 Cmdpos:sample.vim:5:1 Argpos:sample.vim:5:11 Cmd:0xc42005e6c0 Modifiers:[] Range:[] Argopt:map[] Argcmd:map[]} Body:[] Name:0xc42005e700 Params:[0xc42005e740] Attr:{Range:false Abort:false Dict:false Closure:false} EndFunction:0xc4200e37c0}
    node = (*ast.Ident) &{NamePos:sample.vim:5:11 Name:s:g}
      node = (<nil>) <nil>
    node = (*ast.Ident) &{NamePos:sample.vim:5:15 Name:n}
      node = (<nil>) <nil>
    node = (*ast.EndFunction) &{EndFunc:sample.vim:6:1 ExArg:{Forceit:false AddrCount:0 Line1:0 Line2:0 Flags:0 DoEcmdCmd: DoEcmdLnum:0 Append:0 Usefilter:false Amount:0 Regname:0 ForceBin:0 ReadEdit:0 ForceFf: ForceEnc: BadChar: Linepos:sample.vim:6:1 Cmdpos:sample.vim:6:1 Argpos:sample.vim:6:12 Cmd:0xc42005e780 Modifiers:[] Range:[] Argopt:map[] Argcmd:map[]}}
      node = (<nil>) <nil>
    node = (<nil>) <nil>
  node = (<nil>) <nil>

sample.vim

function! s:f()
  call s:g(1 + 1)
endfunction

function! s:g(n)
endfunction

walk.go

package main

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"strings"

	vimlparser "github.com/haya14busa/go-vimlparser"
	"github.com/haya14busa/go-vimlparser/ast"
)

func main() {
	if len(os.Args) < 2 {
		fmt.Println("Usage: <prog> <file>.vim")
		return
	}
	src, err := ioutil.ReadFile(os.Args[1])
	if err != nil {
		panic(err)
	}
	node, err := vimlparser.ParseFile(bytes.NewReader(src), os.Args[1], nil)
	if err != nil {
		panic(err)
	}
	ast.Walk(&visitor{}, node)
}

type visitor struct {
	indent int
}

func (v *visitor) Visit(node ast.Node) ast.Visitor {
	indent := strings.Repeat("  ", v.indent)
	fmt.Printf("%snode = (%T) %+v\n", indent, node, node)
	if node == nil {
		v.indent--
	} else {
		v.indent++
	}
	return v
}