Re: std.conv.to can't convert to bool?

[Jesse Phillips]

Andrej Mitrovic Wrote:

 Wow not a minute later and I get bitten by my own solution. A C
 function returned 1 for a supported feature, and -1 otherwise. And of
 course -1 got converted to true, so then I had a bug in my code.
 
 Damn silly C functions which return -1 when they should return 0.
 
 Or damn me for not RTFM'ing.

Yeah, so the reason it doesn't do that conversion is because it will bite you.

Actually D already uses non-zero as true. Why do you need to cast it?

std.conv.to can't convert to bool?

[Andrej Mitrovic]

import std.stdio;
import std.conv : to;

void main()
{
uint state = 1;
writeln( to!bool(state) );
}

D:\DMD\dmd2\windows\bin\..\..\src\phobos\std\conv.d(99): Error: template 
std.conv.toImpl(T,S) if (!implicitlyConverts!(S,T)  isSomeString!(T)  
isInputRange!(Unqual!(S))  isSomeChar!(ElementType!(S))) does not match any 
function template declaration
D:\DMD\dmd2\windows\bin\..\..\src\phobos\std\conv.d(99): Error: template 
std.conv.toImpl(T,S) if (!implicitlyConverts!(S,T)  isSomeString!(T)  
isInputRange!(Unqual!(S))  isSomeChar!(ElementType!(S))) cannot deduce 
template function from argument types !(bool)(uint)
D:\DMD\dmd2\windows\bin\..\..\src\phobos\std\conv.d(99): Error: template 
instance errors instantiating template
boolConv.d(9): Error: template instance std.conv.to!(bool).to!(uint) error 
instantiating

What's the big problem with converting an int/uint to bool? I'm using a cast 
for now.

Re: std.conv.to can't convert to bool?

[Andrej Mitrovic]

Wow not a minute later and I get bitten by my own solution. A C
function returned 1 for a supported feature, and -1 otherwise. And of
course -1 got converted to true, so then I had a bug in my code.

Damn silly C functions which return -1 when they should return 0.

Or damn me for not RTFM'ing.