以下測(cè)試嘗試使用 AST 向結(jié)構(gòu)添加字段。字段添加正確，但注釋添加順序不正確。我認(rèn)為可能需要手動(dòng)指定位置，但到目前為止我已經(jīng)找到了答案。這是一個(gè)失敗的測(cè)試：http : //play.golang.org/p/RID4N30FZK這是代碼：package generatorimport ( "bytes" "fmt" "go/ast" "go/parser" "go/printer" "go/token" "testing")func TestAst(t *testing.T) { source := `package a// B commenttype B struct { // C comment C string}` fset := token.NewFileSet() file, err := parser.ParseFile(fset, "", []byte(source), parser.ParseComments) if err != nil { t.Error(err) } v := &visitor{ file: file, } ast.Walk(v, file) var output []byte buf := bytes.NewBuffer(output) if err := printer.Fprint(buf, fset, file); err != nil { t.Error(err) } expected := `package a// B commenttype B struct { // C comment C string // D comment D int // E comment E float64}` if buf.String() != expected { t.Error(fmt.Sprintf("Test failed. Expected:\n%s\nGot:\n%s", expected, buf.String())) } /* actual output = `package a// B commenttype B struct { // C comment // D comment // E comment C string D int E float64}` */}type visitor struct { file *ast.File}func (v *visitor) Visit(node ast.Node) (w ast.Visitor) { if node == nil { return v } switch n := node.(type) { case *ast.GenDecl: if n.Tok != token.TYPE { break } ts := n.Specs[0].(*ast.TypeSpec) if ts.Name.Name == "B" { fields := ts.Type.(*ast.StructType).Fields addStructField(fields, v.file, "int", "D", "D comment") addStructField(fields, v.file, "float64", "E", "E comment") } } return v}
2 回答
明月笑刀無(wú)情
TA貢獻(xiàn)1828條經(jīng)驗(yàn) 獲得超4個(gè)贊
我相信我已經(jīng)讓它發(fā)揮作用了。正如我在上面的評(píng)論中所述，所需的要點(diǎn)是：
具體設(shè)置緩沖區(qū)位置包括
Slash和NamePos用于
token.File.AddLine在特定偏移處添加新行（使用第 1 項(xiàng)中的位置計(jì)算）過(guò)度分配源緩沖區(qū)
token.File.Position（由源緩沖區(qū)使用，printer.Printer并且token.File.Addline不會(huì)使源緩沖區(qū)的范圍檢查失敗
代碼：
package main
import (
"bytes"
"fmt"
"go/ast"
"go/parser"
"go/printer"
"go/token"
"testing"
)
func main() {
tests := []testing.InternalTest{{"TestAst", TestAst}}
matchAll := func(t string, pat string) (bool, error) { return true, nil }
testing.Main(matchAll, tests, nil, nil)
}
func TestAst(t *testing.T) {
source := `package a
// B comment
type B struct {
// C comment
C string
}`
buffer := make([]byte, 1024, 1024)
for idx,_ := range buffer {
buffer[idx] = 0x20
}
copy(buffer[:], source)
fset := token.NewFileSet()
file, err := parser.ParseFile(fset, "", buffer, parser.ParseComments)
if err != nil {
t.Error(err)
}
v := &visitor{
file: file,
fset: fset,
}
ast.Walk(v, file)
var output []byte
buf := bytes.NewBuffer(output)
if err := printer.Fprint(buf, fset, file); err != nil {
t.Error(err)
}
expected := `package a
// B comment
type B struct {
// C comment
C string
// D comment
D int
// E comment
E float64
}
`
if buf.String() != expected {
t.Error(fmt.Sprintf("Test failed. Expected:\n%s\nGot:\n%s", expected, buf.String()))
}
}
type visitor struct {
file *ast.File
fset *token.FileSet
}
func (v *visitor) Visit(node ast.Node) (w ast.Visitor) {
if node == nil {
return v
}
switch n := node.(type) {
case *ast.GenDecl:
if n.Tok != token.TYPE {
break
}
ts := n.Specs[0].(*ast.TypeSpec)
if ts.Name.Name == "B" {
fields := ts.Type.(*ast.StructType).Fields
addStructField(v.fset, fields, v.file, "int", "D", "D comment")
addStructField(v.fset, fields, v.file, "float64", "E", "E comment")
}
}
return v
}
func addStructField(fset *token.FileSet, fields *ast.FieldList, file *ast.File, typ string, name string, comment string) {
prevField := fields.List[fields.NumFields()-1]
c := &ast.Comment{Text: fmt.Sprint("// ", comment), Slash: prevField.End() + 1}
cg := &ast.CommentGroup{List: []*ast.Comment{c}}
o := ast.NewObj(ast.Var, name)
f := &ast.Field{
Doc: cg,
Names: []*ast.Ident{&ast.Ident{Name: name, Obj: o, NamePos: cg.End() + 1}},
}
o.Decl = f
f.Type = &ast.Ident{Name: typ, NamePos: f.Names[0].End() + 1}
fset.File(c.End()).AddLine(int(c.End()))
fset.File(f.End()).AddLine(int(f.End()))
fields.List = append(fields.List, f)
file.Comments = append(file.Comments, cg)
}
示例：http : //play.golang.org/p/_q1xh3giHm
對(duì)于Item (3)，將所有過(guò)度分配的字節(jié)設(shè)置為空格 ( 0x20)也很重要，以便打印機(jī)在處理它們時(shí)不會(huì)抱怨空字節(jié)。
- 2 回答
- 0 關(guān)注
- 182 瀏覽
添加回答
舉報(bào)
0/150
提交
取消