Re: regexp font-lock highlighting

[Juri Linkov <juri@jurta.org>]

What were the reasons for making long face names much longer?

After renaming `font-lock-regexp-backslash-construct' it became
absurdly long: `font-lock-regexp-backslash-grouping-construct'.

The face name is not the place for full description of the face.
There are docstrings for that purpose.  But even the new docstring
is less informative than the face name:

"Font Lock mode face used to highlight grouping constructs in Lisp regexps."

Unlike the face name it doesn't mention the word `backslash'.

Long face names cause several problems for users.  For example,
after `M-x customize-face RET' on this face, its name doesn't fit
into the minibuffer:

Customize face (default font-lock-regexp-backslash-grouping-construct): font-lock-regexp-backslash-grouping-construct

In the *Faces* buffer long face names move example alphabets off the screen:

font-lock-doc-face                            abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-function-name-face                  abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-keyword-face                        abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-negation-char-face                  abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-preprocessor-face                   abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-regexp-grouping-backslash           abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-regexp-backslash-grouping-construct abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-string-face                         abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-type-face                           abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-variable-name-face                  abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
font-lock-warning-face                        abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
fringe                                        abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ
header-line                                   abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ

and other inconveniences.

I think the face names proposed by Martin in his latest patch
are much better: `font-lock-regexp-backslash' and
`font-lock-regexp-group'.  These face name have sensible lengths
and are still descriptive enough.

BTW, I noticed that backslashes and grouping characters are more
readable when they both are highlighted in bold, i.e. I also propose
the following change:

Index: lisp/font-lock.el
===================================================================
RCS file: /cvsroot/emacs/emacs/lisp/font-lock.el,v
retrieving revision 1.265
diff -u -r1.265 font-lock.el
--- lisp/font-lock.el	29 Jun 2005 08:19:17 -0000	1.265
+++ lisp/font-lock.el	3 Jul 2005 00:17:25 -0000
@@ -1826,14 +1827,13 @@
   :group 'font-lock-highlighting-faces)
 
-(defface font-lock-regexp-grouping-backslash
-  '((((class color) (min-colors 16)) :inherit escape-glyph)
-    (t :inherit bold))
+(defface font-lock-regexp-backslash
+  '((t :inherit bold))
   "Font Lock mode face for backslashes in Lisp regexp grouping constructs."
   :group 'font-lock-highlighting-faces)
 
-(defface font-lock-regexp-backslash-grouping-construct
+(defface font-lock-regexp-group
   '((t :inherit bold))
-  "Font Lock mode face used to highlight grouping constructs in Lisp regexps."
+  "Font Lock mode face for grouping constructs in Lisp regexps."
   :group 'font-lock-highlighting-faces)

-- 
Juri Linkov
http://www.jurta.org/emacs/