src/pkg/builtin/builtin.go - The Go Programming Language

Golang

Source file src/pkg/builtin/builtin.go

     1	// Copyright 2011 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	/*
     6		Package builtin provides documentation for Go's predeclared identifiers.
     7		The items documented here are not actually in package builtin
     8		but their descriptions here allow godoc to present documentation
     9		for the language's special identifiers.
    10	*/
    11	package builtin
    12	
    13	// bool is the set of boolean values, true and false.
    14	type bool bool
    15	
    16	// uint8 is the set of all unsigned 8-bit integers.
    17	// Range: 0 through 255.
    18	type uint8 uint8
    19	
    20	// uint16 is the set of all unsigned 16-bit integers.
    21	// Range: 0 through 65535.
    22	type uint16 uint16
    23	
    24	// uint32 is the set of all unsigned 32-bit integers.
    25	// Range: 0 through 4294967295.
    26	type uint32 uint32
    27	
    28	// uint64 is the set of all unsigned 64-bit integers.
    29	// Range: 0 through 18446744073709551615.
    30	type uint64 uint64
    31	
    32	// int8 is the set of all signed 8-bit integers.
    33	// Range: -128 through 127.
    34	type int8 int8
    35	
    36	// int16 is the set of all signed 16-bit integers.
    37	// Range: -32768 through 32767.
    38	type int16 int16
    39	
    40	// int32 is the set of all signed 32-bit integers.
    41	// Range: -2147483648 through 2147483647.
    42	type int32 int32
    43	
    44	// int64 is the set of all signed 64-bit integers.
    45	// Range: -9223372036854775808 through 9223372036854775807.
    46	type int64 int64
    47	
    48	// float32 is the set of all IEEE-754 32-bit floating-point numbers.
    49	type float32 float32
    50	
    51	// float64 is the set of all IEEE-754 64-bit floating-point numbers.
    52	type float64 float64
    53	
    54	// complex64 is the set of all complex numbers with float32 real and
    55	// imaginary parts.
    56	type complex64 complex64
    57	
    58	// complex128 is the set of all complex numbers with float64 real and
    59	// imaginary parts.
    60	type complex128 complex128
    61	
    62	// string is the set of all strings of 8-bit bytes, conventionally but not
    63	// necessarily representing UTF-8-encoded text. A string may be empty, but
    64	// not nil. Values of string type are immutable.
    65	type string string
    66	
    67	// int is a signed integer type that is at least 32 bits in size. It is a
    68	// distinct type, however, and not an alias for, say, int32.
    69	type int int
    70	
    71	// uint is an unsigned integer type that is at least 32 bits in size. It is a
    72	// distinct type, however, and not an alias for, say, uint32.
    73	type uint uint
    74	
    75	// uintptr is an integer type that is large enough to hold the bit pattern of
    76	// any pointer.
    77	type uintptr uintptr
    78	
    79	// byte is an alias for uint8 and is equivalent to uint8 in all ways. It is
    80	// used, by convention, to distinguish byte values from 8-bit unsigned
    81	// integer values.
    82	type byte byte
    83	
    84	// rune is an alias for int and is equivalent to int in all ways. It is
    85	// used, by convention, to distinguish character values from integer values.
    86	// In a future version of Go, it will change to an alias of int32.
    87	type rune rune
    88	
    89	// Type is here for the purposes of documentation only. It is a stand-in
    90	// for any Go type, but represents the same type for any given function
    91	// invocation.
    92	type Type int
    93	
    94	// Type1 is here for the purposes of documentation only. It is a stand-in
    95	// for any Go type, but represents the same type for any given function
    96	// invocation.
    97	type Type1 int
    98	
    99	// IntegerType is here for the purposes of documentation only. It is a stand-in
   100	// for any integer type: int, uint, int8 etc.
   101	type IntegerType int
   102	
   103	// FloatType is here for the purposes of documentation only. It is a stand-in
   104	// for either float type: float32 or float64.
   105	type FloatType float32
   106	
   107	// ComplexType is here for the purposes of documentation only. It is a
   108	// stand-in for either complex type: complex64 or complex128.
   109	type ComplexType complex64
   110	
   111	// The append built-in function appends elements to the end of a slice. If
   112	// it has sufficient capacity, the destination is resliced to accommodate the
   113	// new elements. If it does not, a new underlying array will be allocated.
   114	// Append returns the updated slice. It is therefore necessary to store the
   115	// result of append, often in the variable holding the slice itself:
   116	//	slice = append(slice, elem1, elem2)
   117	//	slice = append(slice, anotherSlice...)
   118	func append(slice []Type, elems ...Type) []Type
   119	
   120	// The copy built-in function copies elements from a source slice into a
   121	// destination slice. (As a special case, it also will copy bytes from a
   122	// string to a slice of bytes.) The source and destination may overlap. Copy
   123	// returns the number of elements copied, which will be the minimum of
   124	// len(src) and len(dst).
   125	func copy(dst, src []Type) int
   126	
   127	// The delete built-in function deletes the element with the specified key
   128	// (m[key]) from the map. If there is no such element, delete is a no-op.
   129	// If m is nil, delete panics.
   130	func delete(m map[Type]Type1, key Type)
   131	
   132	// The len built-in function returns the length of v, according to its type:
   133	//	Array: the number of elements in v.
   134	//	Pointer to array: the number of elements in *v (even if v is nil).
   135	//	Slice, or map: the number of elements in v; if v is nil, len(v) is zero.
   136	//	String: the number of bytes in v.
   137	//	Channel: the number of elements queued (unread) in the channel buffer;
   138	//	if v is nil, len(v) is zero.
   139	func len(v Type) int
   140	
   141	// The cap built-in function returns the capacity of v, according to its type:
   142	//	Array: the number of elements in v (same as len(v)).
   143	//	Pointer to array: the number of elements in *v (same as len(v)).
   144	//	Slice: the maximum length the slice can reach when resliced;
   145	//	if v is nil, cap(v) is zero.
   146	//	Channel: the channel buffer capacity, in units of elements;
   147	//	if v is nil, cap(v) is zero.
   148	func cap(v Type) int
   149	
   150	// The make built-in function allocates and initializes an object of type
   151	// slice, map, or chan (only). Like new, the first argument is a type, not a
   152	// value. Unlike new, make's return type is the same as the type of its
   153	// argument, not a pointer to it. The specification of the result depends on
   154	// the type:
   155	//	Slice: The size specifies the length. The capacity of the slice is
   156	//	equal to its length. A second integer argument may be provided to
   157	//	specify a different capacity; it must be no smaller than the
   158	//	length, so make([]int, 0, 10) allocates a slice of length 0 and
   159	//	capacity 10.
   160	//	Map: An initial allocation is made according to the size but the
   161	//	resulting map has length 0. The size may be omitted, in which case
   162	//	a small starting size is allocated.
   163	//	Channel: The channel's buffer is initialized with the specified
   164	//	buffer capacity. If zero, or the size is omitted, the channel is
   165	//	unbuffered.
   166	func make(Type, size IntegerType) Type
   167	
   168	// The new built-in function allocates memory. The first argument is a type,
   169	// not a value, and the value returned is a pointer to a newly
   170	// allocated zero value of that type.
   171	func new(Type) *Type
   172	
   173	// The complex built-in function constructs a complex value from two
   174	// floating-point values. The real and imaginary parts must be of the same
   175	// size, either float32 or float64 (or assignable to them), and the return
   176	// value will be the corresponding complex type (complex64 for float32,
   177	// complex128 for float64).
   178	func complex(r, i FloatType) ComplexType
   179	
   180	// The real built-in function returns the real part of the complex number c.
   181	// The return value will be floating point type corresponding to the type of c.
   182	func real(c ComplexType) FloatType
   183	
   184	// The imag built-in function returns the imaginary part of the complex
   185	// number c. The return value will be floating point type corresponding to
   186	// the type of c.
   187	func imag(c ComplexType) FloatType
   188	
   189	// The close built-in function closes a channel, which must be either
   190	// bidirectional or send-only. It should be executed only by the sender,
   191	// never the receiver, and has the effect of shutting down the channel after
   192	// the last sent value is received. After the last value has been received
   193	// from a closed channel c, any receive from c will succeed without
   194	// blocking, returning the zero value for the channel element. The form
   195	//	x, ok := <-c
   196	// will also set ok to false for a closed channel.
   197	func close(c chan<- Type)
   198	
   199	// The panic built-in function stops normal execution of the current
   200	// goroutine. When a function F calls panic, normal execution of F stops
   201	// immediately. Any functions whose execution was deferred by F are run in
   202	// the usual way, and then F returns to its caller. To the caller G, the
   203	// invocation of F then behaves like a call to panic, terminating G's
   204	// execution and running any deferred functions. This continues until all
   205	// functions in the executing goroutine have stopped, in reverse order. At
   206	// that point, the program is terminated and the error condition is reported,
   207	// including the value of the argument to panic. This termination sequence
   208	// is called panicking and can be controlled by the built-in function
   209	// recover.
   210	func panic(v interface{})
   211	
   212	// The recover built-in function allows a program to manage behavior of a
   213	// panicking goroutine. Executing a call to recover inside a deferred
   214	// function (but not any function called by it) stops the panicking sequence
   215	// by restoring normal execution and retrieves the error value passed to the
   216	// call of panic. If recover is called outside the deferred function it will
   217	// not stop a panicking sequence. In this case, or when the goroutine is not
   218	// panicking, or if the argument supplied to panic was nil, recover returns
   219	// nil. Thus the return value from recover reports whether the goroutine is
   220	// panicking.
   221	func recover() interface{}
   222	
   223	// The error built-in interface type is the conventional interface for
   224	// representing an error condition, with the nil value representing no error.
   225	type error interface {
   226		Error() string
   227	}