'2c3w' cannot be matched only by the second parentheses; the first parentheses must match as well, otherwise the entire match would fail. Given that both the first and the second must have matched successfully, if both $1 and $2 should "retain their values from the last successful match", then $1 should be 2, not 3.

Since /^(?:(?:(\d+(?![rw]))\s*c\s*)|(?:(\d+(?![rc]))\s*w\s*)|(?:(\d+(?![cw]))\s*r\s*))+/i; also works as expected, it seems to me that the definition of "last successful match" might be changing between runs of a repetition.

On the first pass, successful match requires the whole alternation to match before it sets the capture variable, but on subsequent repeats, only the parenthesis need to match before it changes $1?

$_ = 'bb ca de';
/(?:(.)b|.)+/i;
print "Test:             1='$1', 2='$2'\n";
# Prints:  Test:   1='e', 2=''
# vs
$_ = 'e';
/(?:(.)b|.)+/i;
print "Test:             1='$1', 2='$2'\n";
# Prints:  Test:   1='', 2=''

# BUT!
$_ = 'efg';
/(?:(.)b|.)+/i;
print "Test:             1='$1', 2='$2'\n";
# Prints:  Test:   1='', 2=''

[download]

This is all quite strange. The '1w1w' test shows that you don't need $1 to be set in order for it to be stomped, so I've no idea why the 'efg' didn't fail.

All I wanted was to allow users to enter their options in any order!


PS: How does one tell which capture matched, if there is garbage in the other capture variables?

In reply to Re^2: Leaking Regex Captures by SuicideJunkie
in thread Leaking Regex Captures by SuicideJunkie

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