Re: enum sets

On 28/08/2024 21:30, Keith Thompson wrote:

Thiago Adams <thiago.adams@gmail.com> writes:

I am wondering how useful would be to have enum sets.
>
Let´s say you have a function that accepts only monospaced fonts.Then
you can use enum monospaced_font_type. Or a switch case where you need
to check all and only monospaced_font_type.
>
But at same type you can store at same object monospaced_font_type or
font_type.
>
enum font_type
{
     enum monospaced_font_type
     {
         CASCADIA_FONT,
     },
     ARIAL_FONT
};
>
This could be arranged in any way.

 If I understand you correctly, enum monospaced_font_type is a *subtype*
of enum font_type.
 Ada has something very similar to this:
      type Font_Type is (CASCADIA_FONT, ARIAL_FONT);
     subtype monospaced_font_type is Font_type range CASCADIA_FONT .. CASCADIA_FONT;
 An Ada subtype is a type with an optionally added *constraint*,
which can be checked at runtime.  But it's hard to see how you'd
add this to C.
 Given your type definition, how would this behave?
      void func(enum monospaced_font_type);
     enum font_type font = ARIAL_FONT;
     func(font);
 (The Ada equivalent would raise a run-time exception.)
 

Warning because not all font_type are monospaced_font_type.
void func(enum monospaced_font_type);
enum font_type font = ARIAL_FONT;
func(font);
(But all monospaced_font_type are also font_type.)