blob: 074eb722d3fd7d04762125c8178f5501c434b4ec [file] [log] [blame]
package main
import (
"fmt"
"go/ast"
"go/importer"
"go/parser"
"go/token"
"go/types"
"log"
"strings"
)
// !+input
const hello = `
package main
import "fmt"
// append
func main() {
// fmt
fmt.Println("Hello, world")
// main
main, x := 1, 2
// main
print(main, x)
// x
}
// x
`
//!-input
// !+main
func main() {
fset := token.NewFileSet()
f, err := parser.ParseFile(fset, "hello.go", hello, parser.ParseComments)
if err != nil {
log.Fatal(err) // parse error
}
conf := types.Config{Importer: importer.Default()}
pkg, err := conf.Check("cmd/hello", fset, []*ast.File{f}, nil)
if err != nil {
log.Fatal(err) // type error
}
// Each comment contains a name.
// Look up that name in the innermost scope enclosing the comment.
for _, comment := range f.Comments {
pos := comment.Pos()
name := strings.TrimSpace(comment.Text())
fmt.Printf("At %s,\t%q = ", fset.Position(pos), name)
inner := pkg.Scope().Innermost(pos)
if _, obj := inner.LookupParent(name, pos); obj != nil {
fmt.Println(obj)
} else {
fmt.Println("not found")
}
}
}
//!-main
/*
//!+output
$ go build golang.org/x/example/gotypes/lookup
$ ./lookup
At hello.go:6:1, "append" = builtin append
At hello.go:8:9, "fmt" = package fmt
At hello.go:10:9, "main" = func cmd/hello.main()
At hello.go:12:9, "main" = var main int
At hello.go:14:9, "x" = var x int
At hello.go:16:1, "x" = not found
//!-output
*/