Subject: Re: bug#77381: [PATCH] extend tex--prettify-symbols-alist

From: Eli Zaretskii <[email-masked]>
Date: Mon, 31 Mar 2025 15:46:17 +0300

> From: "Paul D. Nelson" <[email-masked]>
> Cc: [email-masked]
> Date: Sun, 30 Mar 2025 21:21:41 +0200
> 
> > I think this function should be in mule.el (under a different name),
> > and it should accept a frame as an additional argument, for which to
> > call display-graphic-p.
> >
> > Otherwise, LGTM, thanks.
> 
> Thanks, please see attached.

Some minor comments:

> +(defun char-graphically-displayable-p (char &optional frame)

I prefer char-displayable-on-frame-p (since "graphically might be
interpreted as meaning only GUI frames).

> +  "Return non-nil if CHAR can be graphically displayed in FRAME.
> +FRAME nil or omitted means use the selected frame.
> +
> +This function provides a more reliable test than `char-displayable-p'
> +for determining if a character will display properly.

"More reliable" will cause people wonder why we have "unreliable"
APIs.  But the essence is not the reliability, the essence is
accuracy: char-displayable-p returns the ability of the entire Emacs
session, whereas this new function returns the ability of a particular
frame.

I also think this function should be documented in the ELisp manual
and in NEWS, but that could be a separate patch.

Thanks.