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Date: Fri, 07 Sep 2018 17:25:17 +0200
From: Steffen Nurpmeso <steffen@...oden.eu>
To: Rich Felker <dalias@...c.org>
Cc: musl@...ts.openwall.com
Subject: Re: Regex: behaviour of ? after () atom
Rich Felker wrote in <20180907151821.GL1878@...ghtrain.aerifal.cx>:
|On Fri, Sep 07, 2018 at 03:38:05PM +0200, Steffen Nurpmeso wrote:
|> Hello.
|>
|> In perl this is
|>
|> $x="print 1 2";
|> if($x =~ /^(:[[:space:]]+)?([^[:space:]]+)(.*)$/){
|> print "<$0> -> <$1> <$2> <$3>\n"
|>}
|>
|> and the result is
|>
|> </tmp/t.pl> -> <> <print> < 1 2>
|>
|> Now the same on AlpineLinux edge and musl-1.1.19-r10 with the MUA
|> i maintain, which uses the normal regex stuff and calls it via
|>
|> echo eins=$3
|> vput vexpr i regex "${3}" \
|> '^(:[[:space:]]+)?([^[:space:]]+)(.*)$' \
|> '<\$0> -> <\$1> <\$2> <\$3>'
|> echo i=$i
|>
|> which in C code does
|>
|> if((reflrv = regcomp(&re, argv[2], reflrv))){
|> ...
|> goto jestr;
|>}
|> fprintf(stderr, "GOING for <%s> -> <%s> %u\n",
|> argv[1],argv[2],n_NELEM(rema));
|> reflrv = regexec(&re, argv[1], n_NELEM(rema), rema, 0);
|>
|> and overall prints
|>
|> eins=print 1 2
|> GOING for <print 1 2> -> <^(:[[:space:]]+)?([^[:space:]]+)(.*)$> 17
|> i=<print 1 2> -> <> <> <>
|>
|> It works correctly if i remove the ()? atom, so i thought i should
|> report that.
|
|What is the value of the flags argument you passed to regcomp?
|
REG_EXTENDED, optional REG_ICASE:
reflrv = REG_EXTENDED;
if(f & a_ICASE)
reflrv |= REG_ICASE;
if((reflrv = regcomp(&re, argv[2], reflrv))){
--steffen
|
|Der Kragenbaer, The moon bear,
|der holt sich munter he cheerfully and one by one
|einen nach dem anderen runter wa.ks himself off
|(By Robert Gernhardt)
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