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go spec: modification of defer statement

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R=r, rsc, ken2, iant
CC=golang-dev
https://golang.org/cl/708041
This commit is contained in:
Robert Griesemer 2010-03-23 17:30:14 -07:00
parent 6b3031beaa
commit 48f0cd2bd5
1 changed files with 17 additions and 5 deletions
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22
doc/go_spec.html
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@ -2996,8 +2996,6 @@ which must be <i>addressable</i>,
that is, either a variable, pointer indirection, array or slice indexing that is, either a variable, pointer indirection, array or slice indexing
operation, operation,
or a field selector of an addressable struct operand. or a field selector of an addressable struct operand.
A function result variable is not addressable.
<!--- (<span class="alert">TODO: remove this restriction.</span>) --->
Given an operand of pointer type, the pointer indirection Given an operand of pointer type, the pointer indirection
operator <code>*</code> retrieves the value pointed operator <code>*</code> retrieves the value pointed
to by the operand. to by the operand.
@ -4281,7 +4279,12 @@ executes, the parameters to the function call are evaluated and saved anew but t
function is not invoked. function is not invoked.
Deferred function calls are executed in LIFO order Deferred function calls are executed in LIFO order
immediately before the surrounding function returns, immediately before the surrounding function returns,
but after the return values, if any, have been evaluated. after the return values, if any, have been evaluated, but before they
are returned to the caller. For instance, if the deferred function is
a <a href="#Function_literals">function literal<a/> and the surrounding
function has <a href="#Function_types">named result parameters</a> that
are in scope within the literal, the deferred function may access and modify
the result parameters before they are returned.
</p> </p>
<pre> <pre>
@ -4292,6 +4295,14 @@ defer unlock(l) // unlocking happens before surrounding function returns
for i := 0; i &lt;= 3; i++ { for i := 0; i &lt;= 3; i++ {
defer fmt.Print(i) defer fmt.Print(i)
} }
// f returns 1
func f() (result int) {
defer func() {
result++
}()
return 0
}
</pre> </pre>
<h2 id="Built-in_functions">Built-in functions</h2> <h2 id="Built-in_functions">Built-in functions</h2>
@ -4928,7 +4939,8 @@ The following minimal alignment properties are guaranteed:
<h2 id="Implementation_differences"><span class="alert">Implementation differences - TODO</span></h2> <h2 id="Implementation_differences"><span class="alert">Implementation differences - TODO</span></h2>
<ul> <ul>
<li><span class="alert">Implementation does not honor the restriction on goto statements and targets (no intervening declarations).</span></li> <li><span class="alert">Implementation does not honor the restriction on goto statements and targets (no intervening declarations).</span></li>
<li><span class="alert">Method expressions are not implemented.</span></li> <li><span class="alert">Method expressions are partially implemented.</span></li>
<li><span class="alert">The implementation of complex numbers is incomplete.</span></li>
<li><span class="alert">Gccgo allows only one init() function per source file.</span></li> <li><span class="alert">Gccgo allows only one init() function per source file.</span></li>
<li><span class="alert">Deferred functions cannot access the surrounding function's result parameters.</span></li>
<li><span class="alert">Function results are not addressable.</span></li>
</ul> </ul>