[Rd] grep problem in R-devel 2.14 r57004

[Simon Urbanek]

I forgot to mention the more obvious ;) - yes, it is a known issue in PCRE 8.13 which is hitting more people.
After re-reading the standard I think the problem was that PCRE did not require enclosing [ to treat [. as special.  This has been addressed in the PCRE trunk since and it also has a comment on what happened. I have ported that fix into R-devel. 

Cheers,
Simon


On Sep 16, 2011, at 9:01 AM, Simon Urbanek wrote:

> Mark, quick googling gives the answer - [.] is not what you think it is, you probably meant [\.]. Bracket expressions starting with [. are collating symbols which is unsupported by PCRE (only [:xxx:] is supported, neither [=xxx=] nor [.xxx.] is) but that's probably not what you intended. See POSIX:
> 
> 9.3.5 RE Bracket Expression
> [...]
> 1. [..] The character sequences "[.", "[=", and "[:" (left-bracket followed by a period, equals-sign, or colon) shall be special inside a bracket expression and are used to delimit collating symbols, equivalence class expressions, and character class expressions.
> 
> Cheers,
> Simon
> 
> 
> 
> On Sep 16, 2011, at 12:45 AM, <Mark.Bravington at csiro.au> <Mark.Bravington at csiro.au> wrote:
> 
>> Problem below with PCRE grep in R-devel; works fine in R-patched. (Unless there's been an absolutely massive change in rules for updated PCRE version 8.13; jeez I hope not)
>> 
>>> grep( '[.][.]', '', perl=TRUE)
>> Error in grep("[.][.]", "", perl = TRUE) :
>> invalid regular expression '[.][.]'
>> In addition: Warning message:
>> In grep("[.][.]", "", perl = TRUE) : PCRE pattern compilation error
>>       'POSIX collating elements are not supported'
>>       at '[.][.]'
>> 
>>> sessionInfo()
>> R Under development (unstable) (2011-09-13 r57004)
>> Platform: i386-pc-mingw32/i386 (32-bit)
>> 
>> locale:
>> [1] LC_COLLATE=English_Australia.1252  LC_CTYPE=English_Australia.1252
>> [3] LC_MONETARY=English_Australia.1252 LC_NUMERIC=C
>> [5] LC_TIME=English_Australia.1252
>> 
>> attached base packages:
>> [1] stats     graphics  grDevices utils     datasets  methods   base
>> 
>> NB I'm sending to R-devel rather than posting a bug report because (i) I have a dim recollection that's what we're supposed to do for bugs in R-devel, and (ii) Bugzilla doesn't include an R-devel version and (iii) couldn't find any guidance on these matters.
>> 
>> Mark
>> 
>> -- 
>> Mark Bravington
>> CSIRO Mathematical & Information Sciences
>> Marine Laboratory
>> Castray Esplanade
>> Hobart 7001
>> TAS
>> 
>> ph (+61) 3 6232 5118
>> fax (+61) 3 6232 5012
>> mob (+61) 438 315 623
>> 
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>> 
>> 
> 
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