libgo/go/reflect/tostring_test.go

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 // Formatting of reflection types and values for debugging.
   6 // Not defined as methods so they do not need to be linked into most binaries;
   7 // the functions are not used by the library itself, only in tests.
   8
   9 package reflect_test
  10
  11 import (
  12         . "reflect"
  13         "strconv"
  14 )
  15
  16 // valueToString returns a textual representation of the reflection value val.
  17 // For debugging only.
  18 func valueToString(val Value) string {
  19         var str string
  20         if !val.IsValid() {
  21                 return "<zero Value>"
  22         }
  23         typ := val.Type()
  24         switch val.Kind() {
  25         case Int, Int8, Int16, Int32, Int64:
  26                 return strconv.FormatInt(val.Int(), 10)
  27         case Uint, Uint8, Uint16, Uint32, Uint64, Uintptr:
  28                 return strconv.FormatUint(val.Uint(), 10)
  29         case Float32, Float64:
  30                 return strconv.FormatFloat(val.Float(), 'g', -1, 64)
  31         case Complex64, Complex128:
  32                 c := val.Complex()
  33                 return strconv.FormatFloat(real(c), 'g', -1, 64) + "+" + strconv.FormatFloat(imag(c), 'g', -1, 64) + "i"
  34         case String:
  35                 return val.String()
  36         case Bool:
  37                 if val.Bool() {
  38                         return "true"
  39                 } else {
  40                         return "false"
  41                 }
  42         case Ptr:
  43                 v := val
  44                 str = typ.String() + "("
  45                 if v.IsNil() {
  46                         str += "0"
  47                 } else {
  48                         str += "&" + valueToString(v.Elem())
  49                 }
  50                 str += ")"
  51                 return str
  52         case Array, Slice:
  53                 v := val
  54                 str += typ.String()
  55                 str += "{"
  56                 for i := 0; i < v.Len(); i++ {
  57                         if i > 0 {
  58                                 str += ", "
  59                         }
  60                         str += valueToString(v.Index(i))
  61                 }
  62                 str += "}"
  63                 return str
  64         case Map:
  65                 t := typ
  66                 str = t.String()
  67                 str += "{"
  68                 str += "<can't iterate on maps>"
  69                 str += "}"
  70                 return str
  71         case Chan:
  72                 str = typ.String()
  73                 return str
  74         case Struct:
  75                 t := typ
  76                 v := val
  77                 str += t.String()
  78                 str += "{"
  79                 for i, n := 0, v.NumField(); i < n; i++ {
  80                         if i > 0 {
  81                                 str += ", "
  82                         }
  83                         str += valueToString(v.Field(i))
  84                 }
  85                 str += "}"
  86                 return str
  87         case Interface:
  88                 return typ.String() + "(" + valueToString(val.Elem()) + ")"
  89         case Func:
  90                 v := val
  91                 return typ.String() + "(" + strconv.FormatUint(uint64(v.Pointer()), 10) + ")"
  92         default:
  93                 panic("valueToString: can't print type " + typ.String())
  94         }
  95 }