Phil Pennock wrote:
Yes, I've had to use the (? prefixes on language bindings where the command options were missing. It's a matter of taste, I guess. If one's not expecting the prefix options, then it's a little more confusing to read, but if one's accustom to using the prefix options then they may even prefer that way.Chiming in because I'm the most recent person to mess with regex functionality (I think). On 2009-02-26 at 23:15 -0800, Jon Strait wrote:1. A new '-s' option to pcre_compile. This is the frequently set PCRE_DOTALL option, allowing the dot character to match a newline as well.This makes sense, since we already have the other common options as flags. In the meantime, you know about the internal option setting feature of PCRE syntax, right? Putting (?s) at the start of the pattern is equivalent.
I understand that the use of UTF-8 is transparent to the Z shell user. This should mean that any character, whether represented as single or multi-byte, will be seen as one character position in a user string. However, the offset numbers that pcre_match will return are representing byte lengths. If one character position is really two bytes, then the PCRE offset will be increased by two, and a mismatch will occur if the user tries to use the offset number for indexing on their user string.On the safe side, regarding the possibility of multi-byte characters, I'm assuming that the returned offset positions are only for sending back to pcre_match and not for indexing on a match string, because the offsets are in byte count, not character count.This is dubious. I can see someone quite reasonably using $var[start,end] for substring extraction; the shell should be internally consistent. In a worst-case scenario, there could be another option to select which offset semantics shall be used. Peter's work on UTF-8 support has so far managed to keep the user from ever knowing or caring about this. Or return four numbers instead of two, so that anyone using the interface has to be aware of the difference and can think about it. I'm not coming up with a more elegant solution.
This is how I understand it, or have I missed something along the way? I'm not that UTF-8 savvy, so maybe there is a way around this that I'm not seeing. Also, I would like to have those two extra offset numbers that represent character positions, but AFAIK, PCRE doesn't provide that info on a match.
Right, the exit status should really be checked anyway instead of my checking the match results. Like so:3. A needed correction: all of the module's external variables are now unset on each match attempt, so that a failed match will be obvious.Well, the exit status is set already. And since the last shell release, we've documented explicitly that nothing is altered: 2009-01-15: * 26312: Phil Pennock: Doc/Zsh/cond.yo, Doc/Zsh/mod_pcre.yo, Doc/Zsh/mod_regex.yo: Document no variables altered on failed match. On the other hand, there's value to a reset too. I don't have a strong preference either way, but now is the time to fix it, before there's been a release which documents the behaviour. :) Part of the problem is that pcre_regex has been in Zsh for many years and we tend to be cautious when changing behaviour. I doubt that anyone is relying on the value being unchanged after a match attempt. Thus the lack of a strong preference. Anyone else? While you're at it, there's also the zsh/regex module which uses the system's normal extended regex libraries and if you're changing the semantics of one, both should change.
pcre_match -b -- $body_match
while [[ $? -eq 0 ]] do
pcre_match -b -n $b -- $body_match
print -l $accum
I'll change it back, unless others think that the new reset actions are worth changing to. The standard behavior is sloppy, but then the whole mechanism is sloppy and it doesn't matter.
Oops, it fails like a winged elephant. I'll put a check in the next patch. Thanks Phil.Could someone please point me to the doc files that would need updating (for the zshmodule man page), or if someone here has that part automated, I can send them whatever targeted write-up they want.Doc/Zsh/mod_pcre.yo (and mod_regex.yo), which are in YODL format.- ret = pcre_exec(pcre_pattern, pcre_hints, *args, strlen(*args), 0, 0, ovec, ovecsize); + ret = pcre_exec(pcre_pattern, pcre_hints, *args, strlen(*args), offset_start, 0, ovec, ovecsize);How gracefully does pcre_exec() fail when offset_start is set to a value larger than the length of the string? To maxint-smallnumber? -Phil