http://d.puremagic.com/issues/show_bug.cgi?id=2971

           Summary: map no longer works with to
           Product: D
           Version: 2.030
          Platform: PC
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: Phobos
        AssignedTo: bugzilla@digitalmars.com
        ReportedBy: k-foley@onu.edu


auto strings = ["1", "2", "3", "4", "5"][];

auto integers = to!(int[])(strings); // fine
auto integers1 = map!("to!(int)(a)")(strings); // fine
auto integers2 = map!(to!(int))(strings); // Error: template instance to!(int)
does not match any template declaration

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Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |andrei@metalanguage.com




--- Comment #1 from Andrei Alexandrescu <andrei@metalanguage.com>  2009-05-13 08:43:30 PDT ---
This is related to the growing concern that I have that Walter is over-relying on unittests to define D. Essentially right now a feature is defined by the maze of related unittests that were defined for it.

I think this approach is good for verifying that the compiler does the right thing, but is by no means a substitute of sound language and compiler design. This has been long forgotten. Many of the recent bugs show how, as soon as you step outside a narrow path defined by the testsuite, everything bursts in flames.

To wit, try these replacements. The error messages show how the compiler has no idea what it's doing. It also gives the user no indication of what might be going wrong.

/*A*/ auto integers2 = map!((a) {return to!int(a);})(strings);

/home/andrei/code/dmd/phobos/std/algorithm.d(120): Error: forward reference to
type __T2
/home/andrei/code/dmd/phobos/std/algorithm.d(120): Error: cannot implicitly
convert expression (null) of type immutable(char)[] to __T2
/home/andrei/code/dmd/phobos/std/algorithm.d(120): Error: forward reference to
inferred return type of function call __dgliteral1(cast(__T2)null)
./test.d(111): Error: template instance
test.main.Map!(__dgliteral1,immutable(char)[][]) error instantiating

/*B*/ auto integers2 = map!(function int(string a) {return
to!int(a);})(strings);

/home/andrei/code/dmd/phobos/std/algorithm.d(94): Error: template
std.algorithm.map(fun...) is not a function template
./test.d(9): Error: template std.algorithm.map(fun...) cannot deduce template
function from argument types !(int function(immutable(char)[] a)
{
return (immutable(char)[] value = value = a;
) , parseString(cast(const(char)[])value);
}
)(immutable(char)[][])
/home/andrei/code/dmd/phobos/std/algorithm.d(9): Error: template instance
std.algorithm.map!(int function(immutable(char)[] a)
{
return (immutable(char)[] value = value = a;
) , parseString(cast(const(char)[])value);
}
) errors instantiating template

We need to change the way the language design is (not) approached, pronto.


Andrei

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Andrei Alexandrescu <andrei@metalanguage.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
         AssignedTo|nobody@puremagic.com        |andrei@metalanguage.com


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Andrei Alexandrescu <andrei@metalanguage.com> changed:

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


--- Comment #2 from Andrei Alexandrescu <andrei@metalanguage.com> 2010-07-11 18:29:07 PDT ---
Changeset 1747.

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