http://d.puremagic.com/issues/show_bug.cgi?id=7962

           Summary: std.regex: Captures.length() returns incorrect value
           Product: D
           Version: D2
          Platform: x86_64
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: nobody@puremagic.com
        ReportedBy: markusle@gmail.com


--- Comment #0 from Markus Dittrich <markusle@gmail.com> 2012-04-21 13:14:03 PDT ---
It seems that Captures.length() from std.regex returns bogus lengths for empty captures (I might be using it improperly). Here's a simple example, the second match object claims length 2 while being empty.

sh-4.2$ uname
Linux

sh-4.2$ dmd | grep "DMD"
DMD64 D Compiler v2.059

sh-4.2$ cat test.d
import std.regex;
import std.stdio;

int main() {

  auto r = regex(r"(@\w+)", "g");

  writeln("match first string  -- looks ok");
  string text1 = "@This is a test";
  auto m1 = match(text1, r);
  auto myCapts1 = m1.captures;
  writeln("content:  ", myCapts1);
  writeln("is empty? ", myCapts1.empty());
  writeln("length:   ", myCapts1.length());

  writeln("");
  writeln("match second string -- length seems wrong");
  string text2 = "(his) is a test";
  auto m2 = match(text2, r);
  auto myCapts2 = m2.captures;
  writeln("content:  ", myCapts2);
  writeln("is empty? ", myCapts2.empty());
  writeln("length :  ", myCapts2.length());

  return 0;
}

sh-4.2$ dmd test.d
sh-4.2$ ./test
match first string  -- looks ok
content:  ["@This", "@This"]
is empty? false
length:   2

match second string -- length seems wrong
content:  []
is empty? true
length :  2

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Dmitry Olshansky <dmitry.olsh@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |pull
                 CC|                            |dmitry.olsh@gmail.com


--- Comment #1 from Dmitry Olshansky <dmitry.olsh@gmail.com> 2012-04-21 14:11:59 PDT ---
(In reply to comment #0)
> It seems that Captures.length() from std.regex returns bogus lengths for empty captures (I might be using it improperly). Here's a simple example, the second match object claims length 2 while being empty.
>

Thanks for the detailed info. The problem is that Captures.length is hardwired to the number of sub captures + 1 which is fine as long as there is a match.

For now you may use m.empty ? 0 : m.length as a workaround.

Pull: https://github.com/D-Programming-Language/phobos/pull/548

P.S. Usage of e.g. length() is deprecated and fails with -property switch. Omit parens for @property members.

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--- Comment #3 from github-bugzilla@puremagic.com 2012-04-22 17:45:36 PDT ---
Commits pushed to master at https://github.com/D-Programming-Language/phobos

https://github.com/D-Programming-Language/phobos/commit/6c9414c8c9f1df9f2c42229cf1b7eb8bd90d076b fix Issue 7962  Captures.length() returns incorrect value

https://github.com/D-Programming-Language/phobos/commit/70ad8e4aaeda91d8c1db19b07ac3e3c3db2d23a6 Merge pull request #548 from blackwhale/fix-captures

fix Issue 7962  Captures.length() returns incorrect value

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Dmitry Olshansky <dmitry.olsh@gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED


--- Comment #4 from Dmitry Olshansky <dmitry.olsh@gmail.com> 2012-04-23 00:18:37 PDT ---
>Does it need to be combined with another switch to "enforce"?

I think it's -w switch that stands for warnings as errors. Or -wi to just enable them. Strange as I thought -property was independent entity.

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