Re: [PATCH] Add prettify symbols to python-mode

[Eli Zaretskii <eliz@gnu.org>]

> From: David Kastrup <dak@gnu.org>
> Cc: xfq.free@gmail.com,  Stromeko@nexgo.de,  emacs-devel@gnu.org
> Date: Wed, 23 Sep 2015 19:58:18 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> From: David Kastrup <dak@gnu.org>
> >> Date: Wed, 23 Sep 2015 18:52:16 +0200
> >> Cc: Xue Fuqiao <xfq.free@gmail.com>, Stromeko@nexgo.de, emacs-devel@gnu.org
> >> 
> >> C may not be a complicated language but it offers no significant
> >> in-language features for integrating data structures and their
> >> manipulators.  As a consequence, working with Elisp data in C does not
> >> resemble either working with C or with Lisp.
> >
> > We have a small set of macros that make this a non-issue.
> 
> Lisp_Object x[2];
> x[0] = a;
> x[1] = b;
> return Fplus (2, x);
> 
> does not resemble either a+b or (+ a b).  A non-issue is something else.

Where's "Elisp data" in this example?

I thought by "working with Elisp data in C" you meant using Lisp data
structures passed to C functions, in which case the following is what
I had in mind (where 'value' is some Lisp data type):

  if (EQ (value, Qunspecified) || (EQ (value, QCignore_defface)))
    return Qt;
  else if (EQ (attribute, QCheight))
    return INTEGERP (value) ? Qnil : Qt;
  else if (CONSP (value) && EQ (XCAR (value), QCwhatever))
    return XCDR (value);
  else
    return Qnil;