Edit report at https://bugs.php.net/bug.php?id=44369&edit=1
ID: 44369
Comment by: root at bugs dot php dot net
Reported by: php at xyzzy dot cjb dot net
Summary: PHP Loop Labels
Status: Not a bug
Type: Feature/Change Request
Package: Feature/Change Request
Operating System: Mac OS X 10.5.2
PHP Version: 5.2.5
Block user comment: N
Private report: N
New Comment:
Did you consider this:
for ($i = 0; $i < 5; ++$i)
{
print "$i: ";
for ($j = 0; $j < 5; ++$j)
{
print "$j ";
if ($j == 2 && $i == 4)
goto END;
}
print "\n";
END:
}
If the label needs to proceed a statement, try LABEL: noop();
Another solution could be to get the the nesting level and use:
continue $nest_level - 1;
Unfortunately, I can find no such function so this would need to be done
manually.
Previous Comments:
------------------------------------------------------------------------
[2008-03-08 18:16:11] php at xyzzy dot cjb dot net
How can this code be rewritten using goto? I downloaded a PHP 6 snapshot and
tried this:
ROW: for ($i = 0; $i < 5; ++$i)
{
print "$i: ";
COLUMN: for ($j = 0; $j < 5; ++$j)
{
print "$j ";
if ($j == 2 && $i == 4)
goto ROW;
}
print "\n";
}
but the entire loop is repeated; it doesn't produce the same output as the
first example.
>From http://www.php.net/~derick/meeting-notes.html#adding-goto (first result
>on Google for "php 6 goto"), I see that there were plans to "reuse the break
>keyword, and extend it with a static label.", but this does not appear to be
>implemented the the latest snapshot. Those meeting notes were from 2005
>however. Google also found http://php6dev.blogspot.com/ but that page is
>currently down so I couldn't read it.
How can I use goto to act as "continue 2" or "break 2"? I also tried:
for ($i = 0; $i < 5; ROW: ++$i)
{
print "$i: ";
for ($j = 0; $j < 5; ++$j)
{
print "$j ";
if ($j == 2 && $i == 4)
goto ROW;
}
print "\n";
}
and: for ($i = 0; ROW: $i < 5; ++$i)
and: for (ROW: $i = 0; $i < 5; ROW: ++$i)
but these all report:
Parse error: syntax error, unexpected ':', expecting ')'
------------------------------------------------------------------------
[2008-03-08 11:41:48] johan...@php.net
PHP 6 has goto which can be used for that.
------------------------------------------------------------------------
[2008-03-08 06:56:00] php at xyzzy dot cjb dot net
Description:
------------
This is an enhancement request to add loop labels to PHP. Currently, to
break out of nested loops, PHP allows you to specify a number to a break
or continue statement. It would increase code clarity and
maintainability to be able to specify a textual label of the loop to
continue or break out of.
This is similar to Bug #29287 "Request: Line labels and goto" except
that I'm not requesting goto, which is what that bug was mostly used to
discuss before being closed. This ticket is specifically for the feature
of adding loop labels, which was not adequately discussed in #29287.
Reproduce code:
---------------
An example of a nested loop (admittedly not a very useful example), how PHP
currently allows you to write it:
for ($i = 0; $i < 5; ++$i)
{
print "$i: ";
for ($j = 0; $j < 5; ++$j)
{
print "$j ";
if ($j == 2 && $i == 4)
continue 2;
}
print "\n";
}
How I would like to be able to write it:
ROW: for ($i = 0; $i < 5; ++$i)
{
print "$i: ";
COLUMN: for ($j = 0; $j < 5; ++$j)
{
print "$j ";
if ($j == 2 && $i == 4)
continue ROW;
}
print "\n";
}
Expected result:
----------------
Both examples should behave the same, if this feature is implemented.
Actual result:
--------------
Parse error: syntax error, unexpected ':' in /private/tmp/a.php on line
2
------------------------------------------------------------------------
--
Edit this bug report at https://bugs.php.net/bug.php?id=44369&edit=1
