universe.go

Documentation: go/types

     1  // Code generated by "go test -run=Generate -write=all"; DO NOT EDIT.
     2  
     3  // Copyright 2011 The Go Authors. All rights reserved.
     4  // Use of this source code is governed by a BSD-style
     5  // license that can be found in the LICENSE file.
     6  
     7  // This file sets up the universe scope and the unsafe package.
     8  
     9  package types
    10  
    11  import (
    12  	"go/constant"
    13  	"strings"
    14  )
    15  
    16  // The Universe scope contains all predeclared objects of Go.
    17  // It is the outermost scope of any chain of nested scopes.
    18  var Universe *Scope
    19  
    20  // The Unsafe package is the package returned by an importer
    21  // for the import path "unsafe".
    22  var Unsafe *Package
    23  
    24  var (
    25  	universeIota       Object
    26  	universeByte       Type // uint8 alias, but has name "byte"
    27  	universeRune       Type // int32 alias, but has name "rune"
    28  	universeAny        Object
    29  	universeError      Type
    30  	universeComparable Object
    31  )
    32  
    33  // Typ contains the predeclared *Basic types indexed by their
    34  // corresponding BasicKind.
    35  //
    36  // The *Basic type for Typ[Byte] will have the name "uint8".
    37  // Use Universe.Lookup("byte").Type() to obtain the specific
    38  // alias basic type named "byte" (and analogous for "rune").
    39  var Typ = []*Basic{
    40  	Invalid: {Invalid, 0, "invalid type"},
    41  
    42  	Bool:          {Bool, IsBoolean, "bool"},
    43  	Int:           {Int, IsInteger, "int"},
    44  	Int8:          {Int8, IsInteger, "int8"},
    45  	Int16:         {Int16, IsInteger, "int16"},
    46  	Int32:         {Int32, IsInteger, "int32"},
    47  	Int64:         {Int64, IsInteger, "int64"},
    48  	Uint:          {Uint, IsInteger | IsUnsigned, "uint"},
    49  	Uint8:         {Uint8, IsInteger | IsUnsigned, "uint8"},
    50  	Uint16:        {Uint16, IsInteger | IsUnsigned, "uint16"},
    51  	Uint32:        {Uint32, IsInteger | IsUnsigned, "uint32"},
    52  	Uint64:        {Uint64, IsInteger | IsUnsigned, "uint64"},
    53  	Uintptr:       {Uintptr, IsInteger | IsUnsigned, "uintptr"},
    54  	Float32:       {Float32, IsFloat, "float32"},
    55  	Float64:       {Float64, IsFloat, "float64"},
    56  	Complex64:     {Complex64, IsComplex, "complex64"},
    57  	Complex128:    {Complex128, IsComplex, "complex128"},
    58  	String:        {String, IsString, "string"},
    59  	UnsafePointer: {UnsafePointer, 0, "Pointer"},
    60  
    61  	UntypedBool:    {UntypedBool, IsBoolean | IsUntyped, "untyped bool"},
    62  	UntypedInt:     {UntypedInt, IsInteger | IsUntyped, "untyped int"},
    63  	UntypedRune:    {UntypedRune, IsInteger | IsUntyped, "untyped rune"},
    64  	UntypedFloat:   {UntypedFloat, IsFloat | IsUntyped, "untyped float"},
    65  	UntypedComplex: {UntypedComplex, IsComplex | IsUntyped, "untyped complex"},
    66  	UntypedString:  {UntypedString, IsString | IsUntyped, "untyped string"},
    67  	UntypedNil:     {UntypedNil, IsUntyped, "untyped nil"},
    68  }
    69  
    70  var aliases = [...]*Basic{
    71  	{Byte, IsInteger | IsUnsigned, "byte"},
    72  	{Rune, IsInteger, "rune"},
    73  }
    74  
    75  func defPredeclaredTypes() {
    76  	for _, t := range Typ {
    77  		def(NewTypeName(nopos, nil, t.name, t))
    78  	}
    79  	for _, t := range aliases {
    80  		def(NewTypeName(nopos, nil, t.name, t))
    81  	}
    82  
    83  	// type any = interface{}
    84  	// Note: don't use &emptyInterface for the type of any. Using a unique
    85  	// pointer allows us to detect any and format it as "any" rather than
    86  	// interface{}, which clarifies user-facing error messages significantly.
    87  	def(NewTypeName(nopos, nil, "any", &Interface{complete: true, tset: &topTypeSet}))
    88  
    89  	// type error interface{ Error() string }
    90  	{
    91  		obj := NewTypeName(nopos, nil, "error", nil)
    92  		obj.setColor(black)
    93  		typ := NewNamed(obj, nil, nil)
    94  
    95  		// error.Error() string
    96  		recv := NewVar(nopos, nil, "", typ)
    97  		res := NewVar(nopos, nil, "", Typ[String])
    98  		sig := NewSignatureType(recv, nil, nil, nil, NewTuple(res), false)
    99  		err := NewFunc(nopos, nil, "Error", sig)
   100  
   101  		// interface{ Error() string }
   102  		ityp := &Interface{methods: []*Func{err}, complete: true}
   103  		computeInterfaceTypeSet(nil, nopos, ityp) // prevent races due to lazy computation of tset
   104  
   105  		typ.SetUnderlying(ityp)
   106  		def(obj)
   107  	}
   108  
   109  	// type comparable interface{} // marked as comparable
   110  	{
   111  		obj := NewTypeName(nopos, nil, "comparable", nil)
   112  		obj.setColor(black)
   113  		typ := NewNamed(obj, nil, nil)
   114  
   115  		// interface{} // marked as comparable
   116  		ityp := &Interface{complete: true, tset: &_TypeSet{nil, allTermlist, true}}
   117  
   118  		typ.SetUnderlying(ityp)
   119  		def(obj)
   120  	}
   121  }
   122  
   123  var predeclaredConsts = [...]struct {
   124  	name string
   125  	kind BasicKind
   126  	val  constant.Value
   127  }{
   128  	{"true", UntypedBool, constant.MakeBool(true)},
   129  	{"false", UntypedBool, constant.MakeBool(false)},
   130  	{"iota", UntypedInt, constant.MakeInt64(0)},
   131  }
   132  
   133  func defPredeclaredConsts() {
   134  	for _, c := range predeclaredConsts {
   135  		def(NewConst(nopos, nil, c.name, Typ[c.kind], c.val))
   136  	}
   137  }
   138  
   139  func defPredeclaredNil() {
   140  	def(&Nil{object{name: "nil", typ: Typ[UntypedNil], color_: black}})
   141  }
   142  
   143  // A builtinId is the id of a builtin function.
   144  type builtinId int
   145  
   146  const (
   147  	// universe scope
   148  	_Append builtinId = iota
   149  	_Cap
   150  	_Clear
   151  	_Close
   152  	_Complex
   153  	_Copy
   154  	_Delete
   155  	_Imag
   156  	_Len
   157  	_Make
   158  	_Max
   159  	_Min
   160  	_New
   161  	_Panic
   162  	_Print
   163  	_Println
   164  	_Real
   165  	_Recover
   166  
   167  	// package unsafe
   168  	_Add
   169  	_Alignof
   170  	_Offsetof
   171  	_Sizeof
   172  	_Slice
   173  	_SliceData
   174  	_String
   175  	_StringData
   176  
   177  	// testing support
   178  	_Assert
   179  	_Trace
   180  )
   181  
   182  var predeclaredFuncs = [...]struct {
   183  	name     string
   184  	nargs    int
   185  	variadic bool
   186  	kind     exprKind
   187  }{
   188  	_Append:  {"append", 1, true, expression},
   189  	_Cap:     {"cap", 1, false, expression},
   190  	_Clear:   {"clear", 1, false, statement},
   191  	_Close:   {"close", 1, false, statement},
   192  	_Complex: {"complex", 2, false, expression},
   193  	_Copy:    {"copy", 2, false, statement},
   194  	_Delete:  {"delete", 2, false, statement},
   195  	_Imag:    {"imag", 1, false, expression},
   196  	_Len:     {"len", 1, false, expression},
   197  	_Make:    {"make", 1, true, expression},
   198  	// To disable max/min, remove the next two lines.
   199  	_Max:     {"max", 1, true, expression},
   200  	_Min:     {"min", 1, true, expression},
   201  	_New:     {"new", 1, false, expression},
   202  	_Panic:   {"panic", 1, false, statement},
   203  	_Print:   {"print", 0, true, statement},
   204  	_Println: {"println", 0, true, statement},
   205  	_Real:    {"real", 1, false, expression},
   206  	_Recover: {"recover", 0, false, statement},
   207  
   208  	_Add:        {"Add", 2, false, expression},
   209  	_Alignof:    {"Alignof", 1, false, expression},
   210  	_Offsetof:   {"Offsetof", 1, false, expression},
   211  	_Sizeof:     {"Sizeof", 1, false, expression},
   212  	_Slice:      {"Slice", 2, false, expression},
   213  	_SliceData:  {"SliceData", 1, false, expression},
   214  	_String:     {"String", 2, false, expression},
   215  	_StringData: {"StringData", 1, false, expression},
   216  
   217  	_Assert: {"assert", 1, false, statement},
   218  	_Trace:  {"trace", 0, true, statement},
   219  }
   220  
   221  func defPredeclaredFuncs() {
   222  	for i := range predeclaredFuncs {
   223  		id := builtinId(i)
   224  		if id == _Assert || id == _Trace {
   225  			continue // only define these in testing environment
   226  		}
   227  		def(newBuiltin(id))
   228  	}
   229  }
   230  
   231  // DefPredeclaredTestFuncs defines the assert and trace built-ins.
   232  // These built-ins are intended for debugging and testing of this
   233  // package only.
   234  func DefPredeclaredTestFuncs() {
   235  	if Universe.Lookup("assert") != nil {
   236  		return // already defined
   237  	}
   238  	def(newBuiltin(_Assert))
   239  	def(newBuiltin(_Trace))
   240  }
   241  
   242  func init() {
   243  	Universe = NewScope(nil, nopos, nopos, "universe")
   244  	Unsafe = NewPackage("unsafe", "unsafe")
   245  	Unsafe.complete = true
   246  
   247  	defPredeclaredTypes()
   248  	defPredeclaredConsts()
   249  	defPredeclaredNil()
   250  	defPredeclaredFuncs()
   251  
   252  	universeIota = Universe.Lookup("iota")
   253  	universeByte = Universe.Lookup("byte").Type()
   254  	universeRune = Universe.Lookup("rune").Type()
   255  	universeAny = Universe.Lookup("any")
   256  	universeError = Universe.Lookup("error").Type()
   257  	universeComparable = Universe.Lookup("comparable")
   258  }
   259  
   260  // Objects with names containing blanks are internal and not entered into
   261  // a scope. Objects with exported names are inserted in the unsafe package
   262  // scope; other objects are inserted in the universe scope.
   263  func def(obj Object) {
   264  	assert(obj.color() == black)
   265  	name := obj.Name()
   266  	if strings.Contains(name, " ") {
   267  		return // nothing to do
   268  	}
   269  	// fix Obj link for named types
   270  	if typ := asNamed(obj.Type()); typ != nil {
   271  		typ.obj = obj.(*TypeName)
   272  	}
   273  	// exported identifiers go into package unsafe
   274  	scope := Universe
   275  	if obj.Exported() {
   276  		scope = Unsafe.scope
   277  		// set Pkg field
   278  		switch obj := obj.(type) {
   279  		case *TypeName:
   280  			obj.pkg = Unsafe
   281  		case *Builtin:
   282  			obj.pkg = Unsafe
   283  		default:
   284  			unreachable()
   285  		}
   286  	}
   287  	if scope.Insert(obj) != nil {
   288  		panic("double declaration of predeclared identifier")
   289  	}
   290  }
   291
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