www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 3508] New: hasLength is broken for length defined as function

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3508

           Summary: hasLength is broken for length defined as function
           Product: D
           Version: 2.036
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: nobody puremagic.com
        ReportedBy: k-foley onu.edu



import std.stdio;

struct Test1 { ulong length(); }
struct Test2 { ulong length; }
struct Test3 { string length; }

/* Definition from std.range

template hasLength(R)
{
    enum bool hasLength = is(typeof(R.init.length) : ulong);
}
*/

template hasLength(R)
{
    enum bool hasLength = is(typeof({
        auto r = R.init;
        auto l = r.length;
        static assert( is(typeof(l) : ulong) );
    }()));
}

int main(string[] args)
{
    writeln( std.range.hasLength!(Test1) ); // false
    writeln( std.range.hasLength!(Test2) ); // true
    writeln( std.range.hasLength!(Test3) ); // false

    writeln( test.hasLength!(Test1) ); // true
    writeln( test.hasLength!(Test2) ); // true
    writeln( test.hasLength!(Test3) ); // false

    return 0;
}

---

I included my proposed fix as test.hasLength.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Nov 14 2009
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3508






 import std.stdio;
 
 struct Test1 { ulong length(); }
 struct Test2 { ulong length; }
 struct Test3 { string length; }
 
 ...


I accidentally left out a few lines at the top (can't edit my original post):

---

module test;

import std.range;

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Nov 14 2009
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3508


Masahiro Nakagawa <repeatedly gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |repeatedly gmail.com
         Resolution|                            |DUPLICATE



10:04:17 PDT ---
*** This issue has been marked as a duplicate of issue 2873 ***

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
May 02 2010