I want to have a template function where I can throw in some stuff in the parameters, then run foreach+static ifs and check what type the current is. From my project clayers[1], I've taken out some parts. (Note the current code does not compile.)
This is what I have so far:


struct XY {size_t x, y;}
alias fg = colorize.fg; //[2]
[...]
void changeSlot(C...)(XY xy, C changes){
    foreach(c; changes){
        static if(is(typeof(c) == dchar) || is(typeof(c) == char))
        {
            slots[xy.y][xy.x].character = c;
        }
        else if(is(typeof(c) == fg))
        {
            slots[xy.y][xy.x].fg = C;
        }
    }
}
[...]
changeSlot(XY(10, 15), fg.red);


For this demonstation I've chosen to only check for `char` and `fg`, but it's intended to check for multiple different types. (See [1])

Now when I try to compile, I get "Error: more than one argument for construction of int" for checking against fg. HOWEVER, the code functions properly when checking the type for characters. From what I understand, my thinking works, but checking with `fg` is causing some crux-flux. `fg` is created from a template, please take a look at [2].

What am I doing wrong when I check for the type of `fg`?

TL;DR: Is there a way to check the type of `fg` with an static if?

[1] = https://github.com/vladdeSV/clayers/blob/change-slot/source/clayers.d#L323
[2] = https://github.com/yamadapc/d-colorize/blob/master/source/colorize/colors.d#L37

On 07/29/2015 10:48 AM, vladde wrote:

>          static if(is(typeof(c) == dchar) || is(typeof(c) == char))
>          {
>              slots[xy.y][xy.x].character = c;
>          }
>          else if(is(typeof(c) == fg))

I don't know whether it is the reason here but you fell for one of the D traps. :( Most definitely, you want an 'else static if' there.

Otherwise, for the fg case, what ends up in your code to be compiled is this:

  if(is(typeof(c) == fg))

Ali

On Wednesday, 29 July 2015 at 17:52:45 UTC, Ali Çehreli wrote:
> On 07/29/2015 10:48 AM, vladde wrote:
>
> >          static if(is(typeof(c) == dchar) || is(typeof(c) ==
> char))
> >          {
> >              slots[xy.y][xy.x].character = c;
> >          }
> >          else if(is(typeof(c) == fg))
>
> I don't know whether it is the reason here but you fell for one of the D traps. :( Most definitely, you want an 'else static if' there.
>
> Otherwise, for the fg case, what ends up in your code to be compiled is this:
>
>   if(is(typeof(c) == fg))
>
> Ali

Apparently, if I only check for a character the code compiles without the need of static if.

if(is(typeof(c) == dchar) || is(typeof(c) == char)){ slots[xy.y][xy.x].character = c; } //Compiles and works as expected

On Wednesday, 29 July 2015 at 18:04:48 UTC, vladde wrote:
> Apparently, if I only check for a character the code compiles without the need of static if.
>
> if(is(typeof(c) == dchar) || is(typeof(c) == char)){ slots[xy.y][xy.x].character = c; } //Compiles and works as expected

And changing all if statements to static if still does not compile.

On 07/29/2015 11:08 AM, vladde wrote:
> On Wednesday, 29 July 2015 at 18:04:48 UTC, vladde wrote:
>> Apparently, if I only check for a character the code compiles without
>> the need of static if.
>>
>> if(is(typeof(c) == dchar) || is(typeof(c) == char)){
>> slots[xy.y][xy.x].character = c; } //Compiles and works as expected
>
> And changing all if statements to static if still does not compile.

The error may be the capital C in the else branch. (?)

Can you provide complete code please? The following compiles with dmd 2.067:

struct XY {size_t x, y;}

private template color_type(int offset)
{
  static enum type : int
  {
    init = 39 + offset,

    black   = 30 + offset,
    red     = 31 + offset,
    green   = 32 + offset,
    yellow  = 33 + offset,
    blue    = 34 + offset,
    magenta = 35 + offset,
    cyan    = 36 + offset,
    white   = 37 + offset,

    light_black   = 90 + offset,
    light_red     = 91 + offset,
    light_green   = 92 + offset,
    light_yellow  = 93 + offset,
    light_blue    = 94 + offset,
    light_magenta = 95 + offset,
    light_cyan    = 96 + offset,
    light_white   = 97 + offset
  }
}

alias color_type!0 .type fg;

// alias fg = colorize.fg; //[2]

void changeSlot(C...)(XY xy, C changes){
    foreach(c; changes){
        static if(is(typeof(c) == dchar) || is(typeof(c) == char))
        {
            // slots[xy.y][xy.x].character = c;
        }
        else if(is(typeof(c) == fg))
        {
            // slots[xy.y][xy.x].fg = C;
        }
    }
}

void main()
{
    changeSlot(XY(10, 15), fg.red);
}

Ali

On Wednesday, 29 July 2015 at 18:14:11 UTC, Ali Çehreli wrote:
>         else if(is(typeof(c) == fg))
>         {
>             // slots[xy.y][xy.x].fg = C;
>         }

The error occurs when the commented line is run. The full code can be viewed at https://github.com/vladdeSV/clayers/blob/change-slot/source/clayers.d

On 07/29/2015 11:54 AM, vladde wrote:
> On Wednesday, 29 July 2015 at 18:14:11 UTC, Ali Çehreli wrote:
>>         else if(is(typeof(c) == fg))
>>         {
>>             // slots[xy.y][xy.x].fg = C;
>>         }
>
> The error occurs when the commented line is run. The full code can be
> viewed at
> https://github.com/vladdeSV/clayers/blob/change-slot/source/clayers.d
>

You seem to be using type names instead of member names:

            static if(is(typeof(c) == dchar) || is(typeof(c) == char))
            {
                slots[xy.y][xy.x].character = c;
            }
            else if(is(typeof(c) == fg))
            {
                slots[xy.y][xy.x].fg = c;

Should be

... color = c;

            }
            else if(is(typeof(c) == bg))
            {
                slots[xy.y][xy.x].bg = c;

... background = c;

            }
            else if(is(typeof(c) == md))
            {
                slots[xy.y][xy.x].md = c;

... mode = c;

            }

Ali

On Wednesday, 29 July 2015 at 22:40:08 UTC, Ali Çehreli wrote:
> You seem to be using type names instead of member names:
>
>             static if(is(typeof(c) == dchar) || is(typeof(c) == char))
>             {
>                 slots[xy.y][xy.x].character = c;
>             }
>             else if(is(typeof(c) == fg))
>             {
>                 slots[xy.y][xy.x].fg = c;
>
> Should be
>
> ... color = c;
>
>             }
>             else if(is(typeof(c) == bg))
>             {
>                 slots[xy.y][xy.x].bg = c;
>
> ... background = c;
>
>             }
>             else if(is(typeof(c) == md))
>             {
>                 slots[xy.y][xy.x].md = c;
>
> ... mode = c;
>
>             }
>
> Ali

Thank you! This was a mistake on my end. Really glad you spotted it, saved me quite some headaches!