Help with font-lock / syntax-propertize-function

Help with font-lock / syntax-propertize-function

[John Mastro]

Hello Emacsers,

I'm trying to customize the fontification done by SQL mode in Emacs 24.4
(the PostgreSQL product, though IIUC that's not relevant to this
situation).

Column names that need to be quoted are put in double quotes. By
default, the text within the double quotes is fontified as if it were
not in quotes. So if I have a column name like "Date of Birth", the word
"Date" is fontified like a type name. (My understanding is that this is
because double quotes are treated as punctuation rather than string
delimiters).

I find that a little distracting - it makes it harder to tell where the
column name starts. What I'd like to do is force the text within double
quotes not to be fontified at all. However, even after reading the
relevant manual sections and some very useful blog posts[1][2] I'm still
not sure how to go about this.

I've cargo-culted some code, unsuccessfully. Any pointers on what I'm
doing wrong?

    (defun my-sql-syntax-propertize-function (beg end)
      (goto-char beg)
      (funcall
       (syntax-propertize-rules
        ((rx "\"" (1+ not-newline) "\"")
         (0 (ignore (my-sql-syntax-propertize-double-quotes)))))))

    (defun my-sql-syntax-propertize-double-quotes ()
      (let ((beg (match-beginning 0))
            (end (match-end 0)))
        (put-text-property beg end 'font-lock-face nil)))

    (defun my-sql-add-syntax-propertize-function ()
      (setq-local syntax-propertize-function
                  #'my-sql-syntax-propertize-function))

    (add-hook 'sql-mode-hook #'my-sql-add-syntax-propertize-function)

Thanks

[1]
http://www.lunaryorn.com/2014/03/12/syntactic-fontification-in-emacs.html
[2]
http://www.lunaryorn.com/2014/06/16/advanced-syntactic-fontification.html

-- 
john

Re: Help with font-lock / syntax-propertize-function

[Stefan Monnier]

> I find that a little distracting - it makes it harder to tell where the
> column name starts. What I'd like to do is force the text within double
> quotes not to be fontified at all.

I think the simplest way to do that is, oddly enough to set the
syntax-table to have the " character be given the " syntax (so that
"..." is then fontified by font-lock with the font-lock-string-face),
and then to customize your font-lock-string-face to look very much like
the default face.


        Stefan

Re: Help with font-lock / syntax-propertize-function

[John Mastro]

Hi Stefan,

Stefan Monnier <monnier@iro.umontreal.ca> wrote:
> I think the simplest way to do that is, oddly enough to set the
> syntax-table to have the " character be given the " syntax (so that
> "..." is then fontified by font-lock with the font-lock-string-face),
> and then to customize your font-lock-string-face to look very much like
> the default face.

Thanks for the reply.

I tried that but it didn't seem to affect fontification. If I run
(modify-syntax-entry ?\" "\"") in a SQL mode buffer, commands like
`kill-sexp' will then work on these column names (which was another of
my goals), but fontification is unaffected (even after M-x
font-lock-fontify-buffer).

Am I modifying the syntax table incorrectly?

By the way, my ideal solution would continue to highlight "real" strings
(those in single quotes) as strings, and only prevent highlighting of
column names (double quoted strings). So if you have any other thoughts
on how to accomplish that, it would be much appreciated.

-- 
john

Re: Help with font-lock / syntax-propertize-function

[Stefan Monnier]

> I tried that but it didn't seem to affect fontification. If I run
> (modify-syntax-entry ?\" "\"") in a SQL mode buffer, commands like
> `kill-sexp' will then work on these column names (which was another of
> my goals), but fontification is unaffected (even after M-x
> font-lock-fontify-buffer).

> Am I modifying the syntax table incorrectly?

I don't know.  I'd need more details.  I suggest you report it as a bug,


        Stefan