| //!+ |
| package main |
| |
| import ( |
| "fmt" |
| "go/ast" |
| "go/importer" |
| "go/parser" |
| "go/token" |
| "go/types" |
| "log" |
| ) |
| |
| const hello = `package main |
| |
| import "fmt" |
| |
| func main() { |
| fmt.Println("Hello, world") |
| }` |
| |
| func main() { |
| fset := token.NewFileSet() |
| |
| // Parse the input string, []byte, or io.Reader, |
| // recording position information in fset. |
| // ParseFile returns an *ast.File, a syntax tree. |
| f, err := parser.ParseFile(fset, "hello.go", hello, 0) |
| if err != nil { |
| log.Fatal(err) // parse error |
| } |
| |
| // A Config controls various options of the type checker. |
| // The defaults work fine except for one setting: |
| // we must specify how to deal with imports. |
| conf := types.Config{Importer: importer.Default()} |
| |
| // Type-check the package containing only file f. |
| // Check returns a *types.Package. |
| pkg, err := conf.Check("cmd/hello", fset, []*ast.File{f}, nil) |
| if err != nil { |
| log.Fatal(err) // type error |
| } |
| |
| fmt.Printf("Package %q\n", pkg.Path()) |
| fmt.Printf("Name: %s\n", pkg.Name()) |
| fmt.Printf("Imports: %s\n", pkg.Imports()) |
| fmt.Printf("Scope: %s\n", pkg.Scope()) |
| } |
| |
| //!- |
| |
| /* |
| //!+output |
| $ go build github.com/golang/example/gotypes/pkginfo |
| $ ./pkginfo |
| Package "cmd/hello" |
| Name: main |
| Imports: [package fmt ("fmt")] |
| Scope: package "cmd/hello" scope 0x820533590 { |
| . func cmd/hello.main() |
| } |
| //!-output |
| */ |