Are you maybe looking for YAPE::Regex::Explain?

By way of presenting its explanations it preaks up regexes
and uses the /x-switch to do still have them execute.

While it is not a "pretty printer", it has all that's needed in it's code.

Other YAPE::Regex-modules may help, too.

Cheers, Sören

I don't know, but I for one don't really believe in syntax coloring or other tools that try to make any code automatically readable.

As an example, take a look at the ugly regex in Decode LaTeX flying accents. The regex is broken to lines with the /x switch to make it readable, but that still doesn't help. The problem with that regex is that I wrote that way back before support of perl 5.10 was universally available, thus the regex does not use named captures, even though it would really need them. An automatic reformatting tool will not provide you meaningful names for the named captures.

Ha, rxrx doesn't like the regex from Decode LaTeX flying accents :)

See Re: ppiwx / wxPPI / wxppixregexp xPPIx_Regexp_linecol_onize / PPIx::Regexp::Element::column_number

Now I've coded up a replacement for YAPE::Regex::Explain, i'm close to posting it, see example at Re: regex help! (regexplain) -- it prettifies the easy way, without altering the original regex (it's eval-able)

rxrx also provides a describe-the-regex thing , but it needs to run it, example

Ignoring the ansi escapes failure on win32, its prettyfied, each () indents, literals are literals ... its a very short hand-editing step from that to qr{}x

Compare to the original //x hand annotated

$_=1234;
m{
  (?<P>(?&V))  # match <V> and save to $+{P} 
  (?<Q> .)     # match <Q> and save to $+{Q}

# this can be saved in $v_definition = qr//
  (?(DEFINE)
    (?<V> ...) # <V> aka (?&V) is three chars
  )
}xm;
[download]

A little search/replace and you have

Oh, duh, here is rxplain output (some perldoc links are broken, todo)

anyone considering consideration to change pre/to/code because of [] shouldn't because there ain't no issue

cperl-beautify-regexp 

cperl-beautify-regexp-piece 

PS: my writeup n° 3000... =)