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