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go spec: introduce rune type

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CC=golang-dev
https://golang.org/cl/5293048
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Robert Griesemer 2011-11-01 01:09:22 -04:00 committed by Russ Cox
parent 2e79e8e549
commit b910a27396
1 changed files with 30 additions and 23 deletions
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53
doc/go_spec.html
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@ -1,5 +1,5 @@
<!-- title The Go Programming Language Specification -->
<!-- subtitle Version of October 17, 2011 -->
<!-- subtitle Version of October 25, 2011 -->
<!--
TODO
@ -691,7 +691,8 @@ float64 the set of all IEEE-754 64-bit floating-point numbers
complex64 the set of all complex numbers with float32 real and imaginary parts
complex128 the set of all complex numbers with float64 real and imaginary parts
byte familiar alias for uint8
byte alias for uint8
rune alias for int (will change to int32 in the future)
</pre>
<p>
@ -711,7 +712,9 @@ uintptr an unsigned integer large enough to store the uninterpreted bits of a p
<p>
To avoid portability issues all numeric types are distinct except
<code>byte</code>, which is an alias for <code>uint8</code>.
<code>byte</code>, which is an alias for <code>uint8</code>, and
<code>rune</code>, which is an alias for <code>int</code> (to become
<code>int32</code> in a later version of Go).
Conversions
are required when different numeric types are mixed in an expression
or assignment. For instance, <code>int32</code> and <code>int</code>
@ -1497,7 +1500,7 @@ The following identifiers are implicitly declared in the universe block:
<pre class="grammar">
Basic types:
bool byte complex64 complex128 float32 float64
int8 int16 int32 int64 string uint8 uint16 uint32 uint64
int8 int16 int32 int64 rune string uint8 uint16 uint32 uint64
Architecture-specific convenience types:
int uint uintptr
@ -1509,7 +1512,7 @@ Zero value:
nil
Functions:
append cap close complex copy imag len
append cap close complex copy delete imag len
make new panic print println real recover
</pre>
@ -1791,11 +1794,15 @@ constant:
</p>
<pre>
var b = true // t has type bool
var i = 0 // i has type int
var f = 3.0 // f has type float64
var c = 1i // c has type complex128
var s = "OMDB" // s has type string
var b = true // t has type bool
var r = 'a' // r has type int
var i = 0 // i has type int
var f = 3.0 // f has type float64
var c0 = 0i // c0 has type complex128
var c1 = 1 + 0i // c1 has type complex128
var c2 = 1 + 1i // c2 has type complex128
var s1 = "OMDB" // s1 has type string
var s2 = `foo` // s2 has type string
</pre>
<h3 id="Short_variable_declarations">Short variable declarations</h3>
@ -3276,11 +3283,11 @@ in any of these cases:
</li>
<li>
<code>x</code> is an integer or has type <code>[]byte</code> or
<code>[]int</code> and <code>T</code> is a string type.
<code>[]rune</code> and <code>T</code> is a string type.
</li>
<li>
<code>x</code> is a string and <code>T</code> is <code>[]byte</code> or
<code>[]int</code>.
<code>[]rune</code>.
</li>
</ul>
@ -3354,9 +3361,8 @@ MyString(0x65e5) // "\u65e5" == "日" == "\xe6\x97\xa5"
</li>
<li>
Converting a value of type <code>[]byte</code> (or
the equivalent <code>[]uint8</code>) to a string type yields a
string whose successive bytes are the elements of the slice. If
Converting a value of type <code>[]byte</code> to a string type yields
a string whose successive bytes are the elements of the slice. If
the slice value is <code>nil</code>, the result is the empty string.
<pre>
@ -3365,12 +3371,13 @@ string([]byte{'h', 'e', 'l', 'l', '\xc3', '\xb8'}) // "hellø"
</li>
<li>
Converting a value of type <code>[]int</code> to a string type yields
a string that is the concatenation of the individual integers
Converting a value of type <code>[]rune</code> to a string type yields
a string that is the concatenation of the individual rune values
converted to strings. If the slice value is <code>nil</code>, the
result is the empty string.
<pre>
string([]int{0x767d, 0x9d6c, 0x7fd4}) // "\u767d\u9d6c\u7fd4" == "白鵬翔"
string([]rune{0x767d, 0x9d6c, 0x7fd4}) // "\u767d\u9d6c\u7fd4" == "白鵬翔"
</pre>
</li>
@ -3385,11 +3392,11 @@ If the string is empty, the result is <code>[]byte(nil)</code>.
</li>
<li>
Converting a value of a string type to <code>[]int</code> yields a
Converting a value of a string type to <code>[]rune</code> yields a
slice containing the individual Unicode code points of the string.
If the string is empty, the result is <code>[]int(nil)</code>.
If the string is empty, the result is <code>[]rune(nil)</code>.
<pre>
[]int(MyString("白鵬翔")) // []int{0x767d, 0x9d6c, 0x7fd4}
[]rune(MyString("白鵬翔")) // []rune{0x767d, 0x9d6c, 0x7fd4}
</pre>
</li>
</ol>
@ -4059,7 +4066,7 @@ For each iteration, iteration values are produced as follows:
Range expression 1st value 2nd value (if 2nd variable is present)
array or slice a [n]E, *[n]E, or []E index i int a[i] E
string s string type index i int see below int
string s string type index i int see below rune
map m map[K]V key k K m[k] V
channel c chan E element e E
</pre>
@ -4077,7 +4084,7 @@ or slice itself. For a <code>nil</code> slice, the number of iterations is 0.
For a string value, the "range" clause iterates over the Unicode code points
in the string starting at byte index 0. On successive iterations, the index value will be the
index of the first byte of successive UTF-8-encoded code points in the string,
and the second value, of type <code>int</code>, will be the value of
and the second value, of type <code>rune</code>, will be the value of
the corresponding code point. If the iteration encounters an invalid
UTF-8 sequence, the second value will be <code>0xFFFD</code>,
the Unicode replacement character, and the next iteration will advance