diff options
| -rw-r--r-- | doc/go_spec.html | 23 |
1 files changed, 17 insertions, 6 deletions
diff --git a/doc/go_spec.html b/doc/go_spec.html index 2e5aa626c..9d8d2b4e0 100644 --- a/doc/go_spec.html +++ b/doc/go_spec.html @@ -3444,7 +3444,8 @@ for true { S() } is the same as for { S() } <p> A "for" statement with a "range" clause -iterates through all entries of an array, slice or map. +iterates through all entries of an array, slice, string or map, +or values received on a channel. For each entry it first assigns the current index or key to an iteration variable - or the current (index, element) or (key, value) pair to a pair of iteration variables - and then executes the block. @@ -3455,20 +3456,30 @@ RangeClause = IdentifierList ( "=" | ":=" ) "range" Expression . </pre> <p> -The type of the right-hand expression in the "range" clause must be an array, -slice or map, or a pointer to an array, slice or map; +The type of the right-hand expression in the "range" clause must be an +array, slice, string or map, or a pointer to an array, slice, string or map; or it may be a channel. -If it is an array, slice or map, +Except for channels, the identifier list must contain one or two identifiers denoting the iteration variables. On each iteration, -the first variable is set to the array or slice index or +the first variable is set to the string, array or slice index or map key, and the second variable, if present, is set to the corresponding -array element or map value. +string or array element or map value. The types of the array or slice index (always <code>int</code>) and element, or of the map key and value respectively, must be assignment compatible to the iteration variables. </p> <p> +For strings, the "range" clause iterates over the Unicode code points +in the string. On successive iterations, the index variable will be the +position of successive UTF-8-encoded code points in the string, and +the second variable, of type <code>int</code>, will be the value of +the corresponding code point. If the iteration encounters an invalid +UTF-8 sequence, the second variable will be <code>0xFFFD</code>, +the Unicode replacement character, and the next iteration will advance +a single byte in the string. +</p> +<p> For channels, the identifier list must contain one identifier. The iteration recieves values sent on the channel until the channel is closed; it does not process the zero value sent before the channel is closed. |