Whew! I've carefully (well, I tried to be careful :-) read through
Apocalypse 5 twice now and it still makes my head hurt (but in a good
way). What follows is some notes that I jotted down and am tired of
looking at. Please correct any misconceptions and feel free to add
where I've omitted.
Here's a quick table of the built-in modifiers that I saw and/or
surmised. Are there any others? (entries with ? are guesses or unknown
on my part)
long form short form meaning
:any :a match returns a list of anywhere the pattern
matches within the string regarless of overlap.
:each :e Apply the pattern each time we can
within the string? Is this what happened
to perl5's /g modifier?
:once :o Match succeeds exactly once (unless .reset)
:words :w Perform a "word match" treating
whitespace between patterns as if it
were \s+
:cont :c Continue from where the last match left off
:ignorecase :i Match alphabetics case insensitively
:perl5? :p5 Match using perl 5 rules
:unicode0? :u0 dot matches bytes
:unicode1? :u1 dot matches code points
:unicode2? :u2 dot matches graphemes
:unicode3? :u3 what dot matches is language dependent
:? :1st succeed on the first match
:? :2nd succeed on the second match
:? :3rd succeed on the third match
:? :4th succeed on the fourth match
This pattern continues for positive integers (i.e. :53rd succeeds on the
fifty-third match) It'd be simpler IMHO, if instead of the "st", "nd",
"rd", and "th" suffixes it were an "n" suffix. e.g., :53n would succeed
on the fifty-third match.
:1time? :1x match exactly one time
:2times? :2x match two times
:3times? :3x match three times
This pattern continues for all positive integers (i.e. :23x matches 23
times) Is the "x" necessary? In a later example s:3/// is used to
perform the s/// 3 times.
Can I use 0 in the above? Will :0 never match? Is there a way to
interpolate the number? Does :$number work?
The text says:
A modifier that starts with a number causes the pattern to match
that many times. It may only be used outside the regex.
Why only outside the RE? Why wouldn't /:3x foo/ be synonymous with
/foo<3>/?
And here's a table of built-in assertions; are there any others?
assertion meaning
<alpha> matches any alphabetic character
<digit> matches any numeric character
<sp> matches a space character
<prior> match whatever the most recently successful match did
<null> match nothing
<commit> fails the match if backtracked to
<cut> fails the match if backtracked to and removes the
portion of the string that matched to that point
<before ...> match if the pattern occurs before ...
<after ...> match if the pattern occurs after ...
The example at the top of Backslash Reform ...
$oldpos = pos $string;
$string =~ m/... <( .pos == $oldpos )> .../;
Shouldn't that first line should be something like
$oldpos = $matchobj.pos; # or ...
$oldpos = pos $matchobj; # or just ...
$oldpos = pos; # uses the most recently seen
# match object
?
End of random ramblings ...
-Scott
--
Jonathan Scott Duff
[EMAIL PROTECTED]
