正規表現の自動生成をするには、正規表現のパーザが必要になるなあ、ということでCPANを探してみたらあった。ラッキー。
YAPE: http://search.cpan.org/~pinyan/YAPE-Regex-3.01/
Regep: http://search.cpan.org/~pinyan/Regexp-Parser-0.10/
同じ人が作っているが、Regexp::Parser の方が新しいものの、YAPE の方が簡単である。YAPE::Regex::Explain というモジュールを使うと、与えた正規表現の解説をしてくれる。それなりに便利かもしれない。
The regular expression:
(?i-msx:reg(ular\s+)?exp?(ression)?)
matches as follows:
NODE EXPLANATION
---------------------------------------------------------
(?i-msx: group, but do not capture (case-insensitive)
(with ^ and $ matching normally) (with . not
matching \n) (matching whitespace and #
normally):
---------------------------------------------------------
reg 'reg'
---------------------------------------------------------
( group and capture to \1 (optional
(matching the most amount possible)):
---------------------------------------------------------
ular 'ular'
---------------------------------------------------------
\s+ whitespace (\n, \r, \t, \f, and " ") (1
or more times (matching the most amount
possible))
---------------------------------------------------------
)? end of \1 (NOTE: because you're using a
quantifier on this capture, only the LAST
repetition of the captured pattern will be
stored in \1)
---------------------------------------------------------
ex 'ex'
---------------------------------------------------------
p? 'p' (optional (matching the most amount
possible))
---------------------------------------------------------
( group and capture to \2 (optional
(matching the most amount possible)):
---------------------------------------------------------
ression 'ression'
---------------------------------------------------------
)? end of \2 (NOTE: because you're using a
quantifier on this capture, only the LAST
repetition of the captured pattern will be
stored in \2)
---------------------------------------------------------
) end of grouping
---------------------------------------------------------
(2004-12-20 12:32:38)Originated from
