Re: isprint, isgraph &c.

[Roberto Ierusalimschy <roberto@...>]

> I see from the list archives that this is a pretty low-demand request,
> but I could do with some way to access isprint and isgraph, in order
> to test whether characters fall into that class.
> 
> The most consistent way with present practice would be to add regex
> character classes for them. Looking at the current list in lstrlib.c,
> the only functions not implemented are indeed isgraph and isprint (as
> well as, correctly unimplemented, the obsolete isascii, and the C99
> isblank).
> 
> So, could we have them, please? The strict definitions in the ISO C
> standard are not as straightforward as isgraph == ispunct || isalnum
> || isspace, isprint == !iscntrl[0], and even if they were, we
> programmers shouldn't have to work that out.

There is a huge problem here. OK, isgraph can be %g, but %p is already
taken (ispunct) ;)

Well, actually the strict definition in the ISO C standard for isgraph
is this:

  The isgraph function tests for any printing character except space (' ').

So, if we add isgraph (as we have %g available), a printing class would
be [%g ] ;)

-- Roberto