[Issue 941] New: std.regexp fails to match when grouping certain sub-expressions

[d-bugmail at puremagic.com]

http://d.puremagic.com/issues/show_bug.cgi?id=941

           Summary: std.regexp fails to match when grouping certain sub-
                    expressions
           Product: D
           Version: 1.005
          Platform: PC
        OS/Version: All
            Status: NEW
          Severity: major
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla at digitalmars.com
        ReportedBy: tom_dlang at yahoo.com.ar


It seems like regular expression pattern matching in phobos is still pretty
buggy.

The following code shows it:

----------------------------------------
import std.regexp;
import std.stdio;

int main() {
    auto str= "foo";
    char[][] re_strs= [
             r"^(h|a|)fo[oas]$",
             r"^(a|b|)fo[oas]$",
             r"^(a|)foo$",
             r"(a|)foo",
             r"^(h|)foo$",
             r"(h|)foo",
             r"(h|a|)fo[oas]",
             r"^(a|b|)fo[o]$",
             r"[abf][ops](o|oo|)(h|a|)",
             r"(h|)[abf][ops](o|oo|)",
             r"(c|)[abf][ops](o|oo|)"
    ];

    foreach (re_str; re_strs) {
        auto re= new RegExp(re_str);
        auto matches= cast(bool)re.test(str);
        writefln("'%s' matches '%s' ? %s", str, re_str, matches);
    }

    for (char c='a'; c<='z'; ++c) {
        auto re_str= "("~c~"|)foo";
        auto re= new RegExp(re_str);
        auto matches= cast(bool)re.test(str);
        writefln("'%s' matches '%s' ? %s", str, re_str, matches);
    }

    return 0;
}
----------------------------------------

All should match but the output is:

----------------------------------------
'foo' matches '^(h|a|)fo[oas]$' ? false
'foo' matches '^(a|b|)fo[oas]$' ? true
'foo' matches '^(a|)foo$' ? true
'foo' matches '(a|)foo' ? true
'foo' matches '^(h|)foo$' ? false
'foo' matches '(h|)foo' ? false
'foo' matches '(h|a|)fo[oas]' ? false
'foo' matches '^(a|b|)fo[o]$' ? true
'foo' matches '[abf][ops](o|oo|)(h|a|)' ? true
'foo' matches '(h|)[abf][ops](o|oo|)' ? false
'foo' matches '(c|)[abf][ops](o|oo|)' ? true
'foo' matches '(a|)foo' ? true
'foo' matches '(b|)foo' ? true
'foo' matches '(c|)foo' ? true
'foo' matches '(d|)foo' ? true
'foo' matches '(e|)foo' ? false
'foo' matches '(f|)foo' ? true
'foo' matches '(g|)foo' ? false
'foo' matches '(h|)foo' ? false
'foo' matches '(i|)foo' ? false
'foo' matches '(j|)foo' ? false
'foo' matches '(k|)foo' ? false
'foo' matches '(l|)foo' ? false
'foo' matches '(m|)foo' ? false
'foo' matches '(n|)foo' ? false
'foo' matches '(o|)foo' ? false
'foo' matches '(p|)foo' ? false
'foo' matches '(q|)foo' ? false
'foo' matches '(r|)foo' ? false
'foo' matches '(s|)foo' ? false
'foo' matches '(t|)foo' ? false
'foo' matches '(u|)foo' ? false
'foo' matches '(v|)foo' ? false
'foo' matches '(w|)foo' ? false
'foo' matches '(x|)foo' ? false
'foo' matches '(y|)foo' ? false
'foo' matches '(z|)foo' ? false
--------------------------------------------

That's a weird one... 

Regards,
--
Tom;


--