Re^2: how can I use regular expresion if my string to be matched has round brackets

In fact, quote meta and \Q\E will actually transform a string usefully (so you can see what escapes to use for next time):

Well, quotemeta and \Q will simple escape any character that isn't a letter, digit or underscore. It doesn't have any knowledge of which characters are special and which aren't, except for the promise that if character that isn't a letter, digit or underscore is escaped, it will never carry a special meaning inside a regexp. I'm not quite sure what you mean by "useful" and "see what escapes to use for next time", but people often frown when commas, spaces and other 'harmless' punctuation characters are escaped in a regexp literal.

Comment on Re^2: how can I use regular expresion if my string to be matched has round brackets

Replies are listed 'Best First'.
Re^3: how can I use regular expresion ... (quotemeta and extending regexes) by moritz (Cardinal) on Oct 06, 2008 at 15:35 UTC
quotemeta is both defined by `s/(\W)/\\$1/` and by "being the function with which you escape strings in regexes", which means that in perl 5, a sequence of a backslash and a non-word-character will always literally match the non-word characters (because otherwise it would break too much existing code). Sadly also no non-word-character can get a new meaning without a preceding backslash, because it would also break stuff. So there remain only a few possible ways in which new features can be introduced syntactically: With modifiers that change the syntax By using one of the rare free escape sequences (`\F, \T, \y, \Y`) By constructs that are now syntactically not valid, because they don't make any sense (perhaps `({...})`, previously `(* ... )`) All of these don't quite help to clean up the syntax, though.	[reply] [d/l] [select]

Replies are listed 'Best First'.

Re^3: how can I use regular expresion ... (quotemeta and extending regexes)
by moritz (Cardinal) on Oct 06, 2008 at 15:35 UTC

quotemeta

s/(\W)/\\$1/

and

Sadly also no non-word-character can get a new meaning without a preceding backslash, because it would also break stuff.

So there remain only a few possible ways in which new features can be introduced syntactically:

With modifiers that change the syntax
By using one of the rare free escape sequences (\F, \T, \y, \Y)
By constructs that are now syntactically not valid, because they don't make any sense (perhaps ({...}), previously (* ... ))

All of these don't quite help to clean up the syntax, though.

[reply]
[d/l]
[select]