I dont find any info on backtrack on tango-D2 regex.

For example, I want to match things like

barFOObar

or

bazFOObaz

so I would use, in PCRE, ^(\w*)FOO($1)$, with $1 meaning the word (given by \w*  that was matced in the first subpattern (\w*)

How to do the samein Tango for D2 (or even phobos for D2)?

On Monday, 16 December 2013 at 07:46:30 UTC, seany wrote:
> I dont find any info on backtrack on tango-D2 regex.
>
> For example, I want to match things like
>
> barFOObar
>
> or
>
> bazFOObaz
>
> so I would use, in PCRE, ^(\w*)FOO($1)$, with $1 meaning the word (given by \w*  that was matced in the first subpattern (\w*)
>
> How to do the samein Tango for D2 (or even phobos for D2)?

have you tried look the docs first?

phobos regex patterns described here
http://dlang.org/phobos/std_regex.html

On Monday, 16 December 2013 at 07:56:53 UTC, evilrat wrote:

>
> have you tried look the docs first?
>
> phobos regex patterns described here
> http://dlang.org/phobos/std_regex.html

The only mention of backtrack is : bmatch
it returns a regex object with a machine state, and last match, but it is still not telling me how to actually do a backtrack match. I.e. if i know the machine state and a match (in my example, does that mean that foo is returned as a match or does it mean thatbaz /bar is returned as a match, and the next attempt will match the bar/baz - if not, then what is the call sequence? bmatch (match bar/baz) then match FOO, then again try to match what bmatch returned?)

On Monday, 16 December 2013 at 07:46:30 UTC, seany wrote:
> I dont find any info on backtrack on tango-D2 regex.
>
> For example, I want to match things like
>
> barFOObar
>
> or
>
> bazFOObaz
>
> so I would use, in PCRE, ^(\w*)FOO($1)$, with $1 meaning the word (given by \w*  that was matced in the first subpattern (\w*)
>
> How to do the samein Tango for D2 (or even phobos for D2)?

Something like http://dpaste.dzfl.pl/0e02c3d1 ? Phobos though.

16-Dec-2013 11:46, seany пишет:
> I dont find any info on backtrack on tango-D2 regex.
>
> For example, I want to match things like
>
> barFOObar
>
> or
>
> bazFOObaz
>
> so I would use, in PCRE, ^(\w*)FOO($1)$, with $1 meaning the word (given
> by \w*  that was matced in the first subpattern (\w*)

With std.regex of Phobos this should just work.

auto re = regex(`^(\w*)FOO\1$`);

assert("barFOObar".match(re));

Syntax is like in JavaScript or Perl.

>
> How to do the samein Tango for D2 (or even phobos for D2)?


-- 
Dmitry Olshansky

16-Dec-2013 12:06, seany пишет:
> On Monday, 16 December 2013 at 07:56:53 UTC, evilrat wrote:
>
>>
>> have you tried look the docs first?
>>
>> phobos regex patterns described here
>> http://dlang.org/phobos/std_regex.html
>
> The only mention of backtrack is : bmatch
> it returns a regex object with a machine state, and last match, but it
> is still not telling me how to actually do a backtrack match.

Docs don't state anything like that. It finds _first_ match and returns full state so that you may continue matching or just look at the current match.

Backtracking is purely irrelevant technical detail.

> I.e. if i
> know the machine state and a match (in my example, does that mean that
> foo is returned as a match or does it mean thatbaz /bar is returned as a
> match, and the next attempt will match the bar/baz - if not, then what
> is the call sequence? bmatch (match bar/baz) then match FOO, then again
> try to match what bmatch returned?)

Simply put match/bmatch will return a range of matches as they are found in the input. Each match is, in turn, a random access range that contains full match, followed by each sub-match in the pattern.

-- 
Dmitry Olshansky

On Monday, 16 December 2013 at 07:46:30 UTC, seany wrote:
> I dont find any info on backtrack on tango-D2 regex.
>
> For example, I want to match things like
>
> barFOObar
>
> or
>
> bazFOObaz
>
> so I would use, in PCRE, ^(\w*)FOO($1)$, with $1 meaning the word (given by \w*  that was matced in the first subpattern (\w*)
>
> How to do the samein Tango for D2 (or even phobos for D2)?

FYI if you know your regex at compile-time, the ctRegex in phobos is *very* fast.

On Monday, 16 December 2013 at 17:20:59 UTC, Dmitry Olshansky wrote:
> 16-Dec-2013 11:46, seany пишет:
>> I dont find any info on backtrack on tango-D2 regex.
>>
>> For example, I want to match things like
>>
>> barFOObar
>>
>> or
>>
>> bazFOObaz
>>
>> so I would use, in PCRE, ^(\w*)FOO($1)$, with $1 meaning the word (given
>> by \w*  that was matced in the first subpattern (\w*)
>
> With std.regex of Phobos this should just work.
>
> auto re = regex(`^(\w*)FOO\1$`);
>
> assert("barFOObar".match(re));
>
> Syntax is like in JavaScript or Perl.
>
>>
>> How to do the samein Tango for D2 (or even phobos for D2)?

thanks! this is what i was looking for (the \1)