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go spec: ... changes

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Also: Fixed a bug in the BuiltinCall production.

R=iant, r, rsc
CC=golang-dev
https://golang.org/cl/2278041
This commit is contained in:
Robert Griesemer 2010-09-24 14:08:28 -07:00
parent 6f32c82953
commit ac771a8a47
1 changed files with 30 additions and 19 deletions
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49
doc/go_spec.html
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@ -1,5 +1,5 @@
<!-- title The Go Programming Language Specification -->
<!-- subtitle Version of Sep 7, 2010 -->
<!-- subtitle Version of Sep 24, 2010 -->
<!--
TODO
@ -994,13 +994,12 @@ type stands for one item of that type. Parameter and result
lists are always parenthesized except that if there is exactly
one unnamed result it may be written as an unparenthesized type.
</p>
<p>
If the function's last parameter has a type prefixed with <code>...</code>,
the function may be invoked with zero or more arguments for that parameter,
each of which must be <a href="#Assignability">assignable</a>
to the type that follows the <code>...</code>.
Such a function is called <i>variadic</i>.
<p>
The final parameter in a function signature may have
a type prefixed with <code>...</code>.
A function with such a parameter is called <i>variadic</i> and
may be invoked with zero or more arguments for that parameter.
</p>
<pre>
@ -2185,7 +2184,8 @@ Selector = "." identifier .
Index = "[" Expression "]" .
Slice = "[" [ Expression ] ":" [ Expression ] "]" .
TypeAssertion = "." "(" Type ")" .
Call = "(" [ ExpressionList [ "," ] ] ")" .
Call = "(" [ ArgumentList [ "," ] ] ")" .
ArgumentList = ExpressionList [ "..." ] .
</pre>
@ -2612,9 +2612,9 @@ then within the function the argument is equivalent to a parameter of type
<code>[]T</code>. At each call of <code>f</code>, the argument
passed to the final parameter is
a new slice of type <code>[]T</code> whose successive elements are
the actual arguments. The length of the slice is therefore the
number of arguments bound to the final parameter and
may differ for each call site.
the actual arguments, which all must be <a href="#Assignability">assignable</a>
to the type <code>T</code>. The length of the slice is therefore the number of
arguments bound to the final parameter and may differ for each call site.
</p>
<p>
@ -2626,20 +2626,31 @@ Greeting("hello:", "Joe", "Anna", "Eileen")
</pre>
<p>
Within <code>Greeting</code>, <code>who</code> will have value
within <code>Greeting</code>, <code>who</code> will have the value
<code>[]string{"Joe", "Anna", "Eileen"}</code>
</p>
<p>
If the final argument is of slice type <code>[]T</code>, it may be passed unchanged as the value
for a <code>...T</code> parameter if the argument is followed by <code>...</code>.
In this case no new slice is created.
</p>
<p>
As a special case, if a function passes its own <code>...</code> parameter
as the <code>...</code> argument in a call to another function with
a <code>...</code> parameter of <a href="#Type_identity">identical type</a>,
the parameter is passed directly. In short, a formal <code>...</code>
parameter is passed unchanged as an actual <code>...</code> parameter provided the
types match.
Given the slice <code>s</code> and call
</p>
<pre>
s := []string{"James", "Jasmine"}
Greeting("goodbye:", s...)
</pre>
<p>
within <code>Greeting</code>, <code>who</code> will have the same value as <code>s</code>
with the same underlying array.
</p>
<h3 id="Operators">Operators</h3>
<p>
@ -4350,7 +4361,7 @@ they cannot be used as function values.
</p>
<pre class="ebnf">
BuiltinCall = identifier "(" [ BuiltinArgs ] ")" .
BuiltinCall = identifier "(" [ BuiltinArgs [ "," ] ] ")" .
BuiltinArgs = Type [ "," ExpressionList ] | ExpressionList .
</pre>