regular expression end tag = start tag - php

Question

Take a look at this regular expression:
(?:\(?")(.+)(?:"\)?)
This regex would match e.g
"a"
("a")
but also
"a)
How can I say that the starting character [ in this case " or ) ] is the same as the ending character? There must be a simplier solution than this, right?
"(.+)"|(?:\(")(.+)(?:"\))

Answer 1

I don't think there's a good way to do this specifically with regex, so you are stuck doing something like this:
/(?:
"(.+)"
|
\( (.+) \)
)/x

Answer 2

how about:
(\(?)(")(.+)\2\1
explanation:
(?-imsx:(\(?)(")(.+)\2\1)
matches as follows:
NODE EXPLANATION
----------------------------------------------------------------------
(?-imsx: group, but do not capture (case-sensitive)
(with ^ and $ matching normally) (with . not
matching \n) (matching whitespace and #
normally):
----------------------------------------------------------------------
( group and capture to \1:
----------------------------------------------------------------------
\(? '(' (optional (matching the most amount
possible))
----------------------------------------------------------------------
) end of \1
----------------------------------------------------------------------
( group and capture to \2:
----------------------------------------------------------------------
" '"'
----------------------------------------------------------------------
) end of \2
----------------------------------------------------------------------
( group and capture to \3:
----------------------------------------------------------------------
.+ any character except \n (1 or more times
(matching the most amount possible))
----------------------------------------------------------------------
) end of \3
----------------------------------------------------------------------
\2 what was matched by capture \2
----------------------------------------------------------------------
\1 what was matched by capture \1
----------------------------------------------------------------------
) end of grouping

Answer 3

You can use Placeholders in PHP. But note, that this is not normal Regex behaviour, its special to PHP.:
preg_match("/<([^>]+)>(.+)<\/\1>/") (the \1 references the outcome of the first match)
This will use the first match as condition for the closing match. This matches <a>something</a> but not <h2>something</a>
However in your case you would need to turn the "(" matched within the first group into a ")" - which wont work.
Update: replacing ( and ) to <BRACE> AND <END_BRACE>. Then you can match using /<([^>]+)>(.+)<END_\1>/. Do this for all Required elements you use: ()[]{}<> and whatevs.
(a) is as nice as [f] will become <BRACE>a<END_BRACE> is as nice as <BRACKET>f<END_BRACKET> and the regex will capture both, if you use preg_match_all
$returnValue = preg_match_all('/<([^>]+)>(.+)<END_\\1>/', '<BRACE>a<END_BRACE> is as nice as <BRACKET>f<END_BRACKET>', $matches);
leads to
array (
0 =>
array (
0 => '<BRACE>a<END_BRACE>',
1 => '<BRACKET>f<END_BRACKET>',
),
1 =>
array (
0 => 'BRACE',
1 => 'BRACKET',
),
2 =>
array (
0 => 'a',
1 => 'f',
),
)