How to use Print method of internal Package

1// Copyright 2014 The Go Authors. All rights reserved.2// Use of this source code is governed by a BSD-style3// license that can be found in the LICENSE file.4// This file implements writing of types. The functionality is lifted5// directly from go/types, but now contains various modifications for6// nicer output.7//8// TODO(gri) back-port once we have a fixed interface and once the9// go/types API is not frozen anymore for the 1.3 release; and remove10// this implementation if possible.11package main12import "go/types"13func (p *printer) writeType(this *types.Package, typ types.Type) {14	p.writeTypeInternal(this, typ, make([]types.Type, 8))15}16// From go/types - leave for now to ease back-porting this code.17const GcCompatibilityMode = false18func (p *printer) writeTypeInternal(this *types.Package, typ types.Type, visited []types.Type) {19	// Theoretically, this is a quadratic lookup algorithm, but in20	// practice deeply nested composite types with unnamed component21	// types are uncommon. This code is likely more efficient than22	// using a map.23	for _, t := range visited {24		if t == typ {25			p.printf("○%T", typ) // cycle to typ26			return27		}28	}29	visited = append(visited, typ)30	switch t := typ.(type) {31	case nil:32		p.print("<nil>")33	case *types.Basic:34		if t.Kind() == types.UnsafePointer {35			p.print("unsafe.")36		}37		if GcCompatibilityMode {38			// forget the alias names39			switch t.Kind() {40			case types.Byte:41				t = types.Typ[types.Uint8]42			case types.Rune:43				t = types.Typ[types.Int32]44			}45		}46		p.print(t.Name())47	case *types.Array:48		p.printf("[%d]", t.Len())49		p.writeTypeInternal(this, t.Elem(), visited)50	case *types.Slice:51		p.print("[]")52		p.writeTypeInternal(this, t.Elem(), visited)53	case *types.Struct:54		n := t.NumFields()55		if n == 0 {56			p.print("struct{}")57			return58		}59		p.print("struct {\n")60		p.indent++61		for i := 0; i < n; i++ {62			f := t.Field(i)63			if !f.Anonymous() {64				p.printf("%s ", f.Name())65			}66			p.writeTypeInternal(this, f.Type(), visited)67			if tag := t.Tag(i); tag != "" {68				p.printf(" %q", tag)69			}70			p.print("\n")71		}72		p.indent--73		p.print("}")74	case *types.Pointer:75		p.print("*")76		p.writeTypeInternal(this, t.Elem(), visited)77	case *types.Tuple:78		p.writeTuple(this, t, false, visited)79	case *types.Signature:80		p.print("func")81		p.writeSignatureInternal(this, t, visited)82	case *types.Interface:83		// We write the source-level methods and embedded types rather84		// than the actual method set since resolved method signatures85		// may have non-printable cycles if parameters have anonymous86		// interface types that (directly or indirectly) embed the87		// current interface. For instance, consider the result type88		// of m:89		//90		//     type T interface{91		//         m() interface{ T }92		//     }93		//94		n := t.NumMethods()95		if n == 0 {96			p.print("interface{}")97			return98		}99		p.print("interface {\n")100		p.indent++101		if GcCompatibilityMode {102			// print flattened interface103			// (useful to compare against gc-generated interfaces)104			for i := 0; i < n; i++ {105				m := t.Method(i)106				p.print(m.Name())107				p.writeSignatureInternal(this, m.Type().(*types.Signature), visited)108				p.print("\n")109			}110		} else {111			// print explicit interface methods and embedded types112			for i, n := 0, t.NumExplicitMethods(); i < n; i++ {113				m := t.ExplicitMethod(i)114				p.print(m.Name())115				p.writeSignatureInternal(this, m.Type().(*types.Signature), visited)116				p.print("\n")117			}118			for i, n := 0, t.NumEmbeddeds(); i < n; i++ {119				typ := t.Embedded(i)120				p.writeTypeInternal(this, typ, visited)121				p.print("\n")122			}123		}124		p.indent--125		p.print("}")126	case *types.Map:127		p.print("map[")128		p.writeTypeInternal(this, t.Key(), visited)129		p.print("]")130		p.writeTypeInternal(this, t.Elem(), visited)131	case *types.Chan:132		var s string133		var parens bool134		switch t.Dir() {135		case types.SendRecv:136			s = "chan "137			// chan (<-chan T) requires parentheses138			if c, _ := t.Elem().(*types.Chan); c != nil && c.Dir() == types.RecvOnly {139				parens = true140			}141		case types.SendOnly:142			s = "chan<- "143		case types.RecvOnly:144			s = "<-chan "145		default:146			panic("unreachable")147		}148		p.print(s)149		if parens {150			p.print("(")151		}152		p.writeTypeInternal(this, t.Elem(), visited)153		if parens {154			p.print(")")155		}156	case *types.Named:157		s := "<Named w/o object>"158		if obj := t.Obj(); obj != nil {159			if pkg := obj.Pkg(); pkg != nil {160				if pkg != this {161					p.print(pkg.Path())162					p.print(".")163				}164				// TODO(gri): function-local named types should be displayed165				// differently from named types at package level to avoid166				// ambiguity.167			}168			s = obj.Name()169		}170		p.print(s)171	default:172		// For externally defined implementations of Type.173		p.print(t.String())174	}175}176func (p *printer) writeTuple(this *types.Package, tup *types.Tuple, variadic bool, visited []types.Type) {177	p.print("(")178	for i, n := 0, tup.Len(); i < n; i++ {179		if i > 0 {180			p.print(", ")181		}182		v := tup.At(i)183		if name := v.Name(); name != "" {184			p.print(name)185			p.print(" ")186		}187		typ := v.Type()188		if variadic && i == n-1 {189			p.print("...")190			typ = typ.(*types.Slice).Elem()191		}192		p.writeTypeInternal(this, typ, visited)193	}194	p.print(")")195}196func (p *printer) writeSignature(this *types.Package, sig *types.Signature) {197	p.writeSignatureInternal(this, sig, make([]types.Type, 8))198}199func (p *printer) writeSignatureInternal(this *types.Package, sig *types.Signature, visited []types.Type) {200	p.writeTuple(this, sig.Params(), sig.Variadic(), visited)201	res := sig.Results()202	n := res.Len()203	if n == 0 {204		// no result205		return206	}207	p.print(" ")208	if n == 1 && res.At(0).Name() == "" {209		// single unnamed result210		p.writeTypeInternal(this, res.At(0).Type(), visited)211		return212	}213	// multiple or named result(s)214	p.writeTuple(this, res, false, visited)215}...

1import (2func main() {3	internal.Print()4}5import (6func Print() {7	fmt.Println("Hello, world!")8}9import (10func main() {11	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {12		fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))13	})14	http.ListenAndServe(":8080", nil)15}16import (17func main() {18	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {19		fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))20	})21	http.ListenAndServe(":8080", nil)22}23import (24func main() {25	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {26		fmt.Fprintf(w, "Hello, %q", html.EscapeString(r.URL.Path))27	})28	http.ListenAndServe(":8080", nil)29}

1import (2func main() {3    internal.Print()4}5import "fmt"6func Print() {7    fmt.Println("Hello World")8}

1import "internal"2func main() {3 int := internal.New()4 int.Print()5}6import "internal"7func main() {8 int := internal.New()9 int.Print()10}11import "fmt"12type Internal struct{}13func (i *Internal) Print() {14 fmt.Println("Hello from internal package")15}16func New() *Internal {17 return &Internal{}18}

1import (2func main() {3    fmt.Println("Hello World!")4    _1.Print()5}6import "fmt"7func Print() {8    fmt.Println("Hello World!")9}

1import (2func main() {3    i.Print()4}5import (6func main() {7    i.Print()8}9import (10func main() {11    i.Print()12}13import (14func main() {15    i.Print()16}

1import (2func main() {3	fmt.Println("Print method of internal class")4	obj := internal.Print()5	fmt.Println(obj)6}7func Print() string {8}9import (10func main() {11	fmt.Println("Print method of internal class")12	obj := internal.Print()13	fmt.Println(obj)14}15func Print() string {16}17import (18func main() {19	fmt.Println("Print method of internal class")20	obj := internal.Print()21	fmt.Println(obj)22}23func Print() string {24}25import (26func main() {27	fmt.Println("Print method of internal class")28	obj := internal.Print()29	fmt.Println(obj)30}31func Print() string {32}33import (34func main() {