template specialization for arrays

[J Arrizza]

>
> You should use either std.traits.isXxx systematically, or patterns
>> systematically, but not both at the same time. Personally I prefer isXxx
>> because they foster simple logic to decide what overloads should apply.
>
>
> Also, when posting, you may want to include complete short programs so
> others can try them quickly.


Andrei, I thought I had posted the entire program. Here it is again using
only traits as you recommend:

import std.stdio;
import std.traits;
void abc(T) (T parm1)
  if (isNarrowString!T || (!isStaticArray!T && !isDynamicArray!T))
  {
  writeln("simpleparm: ", parm1);
  }
void abc(T) (T parm1)
  if (!isNarrowString!T && (isDynamicArray!T || isStaticArray!T) )
  {
  writeln("array : ", parm1);
  }
void main(string[] args)
  {
    writeln("v4");
    abc(1);
    abc("str");
    int[] arr = [1, 2];
    abc(arr);
    int[2] arr2 = [3, 4];
    abc(arr2);
  }

And it does work, here's the output:

simpleparm: 1
simpleparm: str
array : [1, 2]
array : [3, 4]


Note my original intent was to differentiate between arrays and non-arrays
only (lumping strings into non-array).

As for using only patterns, I can't get the compiler to disambiguate
between non-arrays and arrays:

import std.stdio;
import std.traits;
void abc(T, U = void, size_t N = 0) (T parm1)   //line 3
  {
  writeln("simpleparm: ", parm1);
  }
void abc(T: U[N], U = char, size_t N) (T parm1)
  {
  writeln("string : ", parm1);
  }
void abc(T) (T parm1)
  {
  writeln("dynamic array : ", parm1);
  }
void abc(T: U[N], U, size_t N) (T parm1)     //line 15
  {
  writeln("static array : ", parm1);
  }
void main(string[] args)
  {
    writeln("v4");
    abc(1);
    abc("str");
    int[] arr = [1, 2];
    abc(arr);
    int[2] arr2 = [3, 4];
    abc(arr2);                //line 27
  }


Here's the compiler error:

dtest.d(27): Error: template dtest.abc(T,U = void,ulong N = 0) abc(T,U =
void,ulong N = 0) matches more than one template declaration,
dtest.d(3):abc(T,U = void,ulong N = 0) and dtest.d(15):abc(T : U[N],U,ulong
N)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.puremagic.com/pipermail/digitalmars-d/attachments/20111030/e25c8f0f/attachment-0001.html>