On Sat, 23 Jun 2012 03:40:15 +0200 Roland Mainz wrote:
> On Sat, Jun 23, 2012 at 2:34 AM, Roland Mainz <roland.ma...@nrubsig.org>
> wrote:
> > Hi!
> >
> > ----
> >
> > Here's another issue with regex. We wrote the following script to
> > parse XML fragments:
> > -- snip --
> > typeset -r xmltext='<h1 ><div> a text </div>More [TEXT].<!-- a comment
> > (<disabled>) --></h1>'
> >
> > #
> > # parse the XML data
> > #
> > typeset dummy
> >
> > dummy="${xmltext//~(Ex)(?:
> > (<!--.+-->)+?| # xml comments
> > (<[[:alnum:]_-:]+
> > (?: # attributes
> > [:space:]+
> Grumpf... this should be [[:space:]]+ ...
> > (?:[[:alnum:]_-:]+=[^[:space:]\"\']+)| #x='foo=bar
> > huz=123'
> > (?:[[:alnum:]_-:]+=\"[^\"]*\")|
> > #x='foo="ba=r o" huz=123'
> > (?:[[:alnum:]_-:]+=\'[^\"]*\')|
> > #x="foo='ba=r o' huz=123"
> > (?:[[:alnum:]_-:]+) #x="foox
> > huz=123"
> > )*
> > [:space:]*
> Grumpf... this should be [[:space:]]* ...
> Erm... David/Glenn... can we get a ~(<modifer>) flag which enables...
> 1. ... strict pattern interpretation
> 2. ... forces (controlled by ~(<modifer>) ... unless there's something
> else which already enabled that elsewhere (like a global shell
> option)) ksh93 to print runtime error messages if a pattern fails to
> compile
> ... please ?
well again I think this is regex giving users enough rope to do whatever
[:space:] is a valid RE
in this example it happens to be a typo
in another context where, e.g., [...] classes are constructed by code,
its possible for duplicates to appear in the class
regex should not be expected to complain about syntactically correct patterns
if the pattern did have a syntax error regcomp() would report it to the caller
so reporting an error or not is not a regex issue
so it doesn't make sense to add something to ~(...) to check syntax
because regcomp() already does it by default (modulo the ast REG_LENIENT flag,
which
is settable in ~(...))
_______________________________________________
ast-developers mailing list
ast-developers@research.att.com
https://mailman.research.att.com/mailman/listinfo/ast-developers
