抽象语法树 (AST) 扫描
abstract syntax tree (AST) scan
我正在尝试从 go AST 中提取函数调用:
$ cat main.go
package main
import ("fmt"; "go/ast"; "go/token"; "go/parser"; "io/ioutil")
func CalledFuncs(n ast.Node) bool {
switch n.(type) {
case *ast.CallExpr:
l := ast.CallExpr(n).Lparen
r := ast.CallExpr(n).Right
fmt.Printf("call %d( ... %d)\n",l,r)
}
return true
}
func main() {
fset := token.NewFileSet()
src,_ := ioutil.ReadFile("simple.go")
f, _ := parser.ParseFile(fset,">>",src,0)
ast.Inspect(f, CalledFuncs)
}
但是 go 编译器抱怨我不能做转换:
$ go build -o main main.go
# command-line-arguments
./main.go:7:26: cannot convert n (type ast.Node) to type ast.CallExpr
./main.go:8:26: cannot convert n (type ast.Node) to type ast.CallExpr
我可能漏掉了什么。
https://golang.org/ref/spec#Type_switches
The TypeSwitchGuard
may include a short variable declaration. When
that form is used, the variable is declared at the end of the
TypeSwitchCase
in the implicit block of each clause. In clauses with a
case listing exactly one type, the variable has that type; otherwise,
the variable has the type of the expression in the TypeSwitchGuard
.
这意味着您可以执行以下操作:
func CalledFuncs(n ast.Node) bool {
switch x := n.(type) {
case *ast.CallExpr:
l := x.Lparen
r := x.Rparen
fmt.Printf("call %d( ... %d)\n", l, r)
}
return true
}
我正在尝试从 go AST 中提取函数调用:
$ cat main.go
package main
import ("fmt"; "go/ast"; "go/token"; "go/parser"; "io/ioutil")
func CalledFuncs(n ast.Node) bool {
switch n.(type) {
case *ast.CallExpr:
l := ast.CallExpr(n).Lparen
r := ast.CallExpr(n).Right
fmt.Printf("call %d( ... %d)\n",l,r)
}
return true
}
func main() {
fset := token.NewFileSet()
src,_ := ioutil.ReadFile("simple.go")
f, _ := parser.ParseFile(fset,">>",src,0)
ast.Inspect(f, CalledFuncs)
}
但是 go 编译器抱怨我不能做转换:
$ go build -o main main.go
# command-line-arguments
./main.go:7:26: cannot convert n (type ast.Node) to type ast.CallExpr
./main.go:8:26: cannot convert n (type ast.Node) to type ast.CallExpr
我可能漏掉了什么。
https://golang.org/ref/spec#Type_switches
The
TypeSwitchGuard
may include a short variable declaration. When that form is used, the variable is declared at the end of theTypeSwitchCase
in the implicit block of each clause. In clauses with a case listing exactly one type, the variable has that type; otherwise, the variable has the type of the expression in theTypeSwitchGuard
.
这意味着您可以执行以下操作:
func CalledFuncs(n ast.Node) bool {
switch x := n.(type) {
case *ast.CallExpr:
l := x.Lparen
r := x.Rparen
fmt.Printf("call %d( ... %d)\n", l, r)
}
return true
}