• David Held (23/23) May 03 2014 import std.algorithm;
• Jonathan M Davis via Digitalmars-d-learn (9/36) May 03 2014 On Sat, 03 May 2014 14:47:56 -0700

David Held <dmd wyntrmute.com> writes:

import std.algorithm;

int toInt(char c) { return 1; }

void main()
{
     map!(a => toInt(a))("hello");
}

Can someone please explain why I get this:

Bug.d(10): Error: function Bug.toInt (char c) is not callable using 
argument types (dchar)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
D:\D\dmd2\windows\bin\..\..\src\phobos\std\algorithm.d(425): Error: 
template instance Bug.main.__lambda1!dchar error instantiating
D:\D\dmd2\windows\bin\..\..\src\phobos\std\algorithm.d(411): 
instantiated from here: MapResult!(__lambda1, string)
Bug.d(10):        instantiated from here: map!string
D:\D\dmd2\windows\bin\..\..\src\phobos\std\algorithm.d(411): Error: 
template instance Bug.main.MapResult!(__lambda1, string) error instantiating
Bug.d(10):        instantiated from here: map!string
Bug.d(10): Error: template instance Bug.main.map!((a) => 
toInt(a)).map!string error instantiating

I thought that string == immutable char[], but this implies that it is 
getting inferred as dchar[], I guess.

Dave

Jonathan M Davis via Digitalmars-d-learn writes:

On Sat, 03 May 2014 14:47:56 -0700
David Held via Digitalmars-d-learn <digitalmars-d-learn puremagic.com>
wrote:

 import std.algorithm;
 
 int toInt(char c) { return 1; }
 
 void main()
 {
      map!(a => toInt(a))("hello");
 }
 
 Can someone please explain why I get this:
 
 Bug.d(10): Error: function Bug.toInt (char c) is not callable using 
 argument types (dchar)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 D:\D\dmd2\windows\bin\..\..\src\phobos\std\algorithm.d(425): Error: 
 template instance Bug.main.__lambda1!dchar error instantiating
 D:\D\dmd2\windows\bin\..\..\src\phobos\std\algorithm.d(411): 
 instantiated from here: MapResult!(__lambda1, string)
 Bug.d(10):        instantiated from here: map!string
 D:\D\dmd2\windows\bin\..\..\src\phobos\std\algorithm.d(411): Error: 
 template instance Bug.main.MapResult!(__lambda1, string) error
 instantiating Bug.d(10):        instantiated from here: map!string
 Bug.d(10): Error: template instance Bug.main.map!((a) => 
 toInt(a)).map!string error instantiating
 
 I thought that string == immutable char[], but this implies that it
 is getting inferred as dchar[], I guess.

All strings are treated as ranges of dchar by Phobos.

http://stackoverflow.com/questions/12288465

If you really want to operate on strings as ranges of code units rather
than code points, then you need to use std.string.representation and
convert them to the equivalent integral types (e.g. immutable(ubyte)[]).


- Jonathan M Davis