Re: enum sets

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.)

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */