Re: Union tag comparison

[Mural <mail@xxxxxxx>]

On Wed, Feb 12, 2020, at 10:34 AM, ori@xxxxxxxxxxxxxx wrote:
> > Hello,
> > 
> > Say, I have a 
> > type expr = union
> >     `Oadd(expr#, expr#)
> >     `Oneg(expr#)
> > ;;
> > 
> > I want to compare two expr values to determine whether they are of the same Op.
> > As I know, I can define a function that maps each variant into a distinct integer or string.
> > But It'd be nice if it can be as simple as how C  does: 'a.Op == b.Op'.
> > I am thinking about a builtin function that retrieves the internal integer value of the union tag.
> > Am I missing something?
> 
> Seems sane-enough. I'd prefer if instead of a function, it was a magic 
> '.tag' member,
> kind of like '.len' on arrays.
> 
Noted.
Thanks.