What is this syntax for in php-mode.el

What is this syntax for in php-mode.el

[Lennart Borgman (gmail)]

I am looking at php-mode.el from Turadg. I can not understand this:

(defconst php-font-lock-syntactic-keywords
   (if xemacsp nil
     ;; Mark shell-style comments.  font-lock handles this in a
     ;; separate pass from normal syntactic scanning (somehow), so we
     ;; get a chance to mark these in addition to C and C++ style
     ;; comments.  This only works in GNU Emacs, not XEmacs 21 which
     ;; seems to ignore this same code if we try to use it.
     (list
      ;; Mark _all_ # chars as being comment-start.  That will be
      ;; ignored when inside a quoted string.
      '("\\(\#\\)"
        (1 (11 . nil)))
      ;; Mark all newlines ending a line with # as being comment-end.
      ;; This causes a problem, premature end-of-comment, when '#'
      ;; appears inside a multiline C-style comment.  Oh well.
      '("#.*\\([\n]\\)"
        (1 (12 . nil)))
      )))

What is it for? Does php use # as a comment somewhere?

And what about the format for the list entries? I tried to look at 
font-lock-syntactic-keywords, but I can not see that these entries 
follows the spec there.

How does this work?

Re: What is this syntax for in php-mode.el

[Edward O'Connor]

Lennart asked:

> What is it for? Does php use # as a comment somewhere?

PHP has (at least) three comment syntaxes:

  /* ... */
  // ... EOL
  # ... EOL


Ted

-- 
Edward O'Connor
hober0@gmail.com

Ense petit placidam sub libertate quietem.

Re: What is this syntax for in php-mode.el

[Lennart Borgman (gmail)]

Edward O'Connor wrote:
> Lennart asked:
> 
>> What is it for? Does php use # as a comment somewhere?
> 
> PHP has (at least) three comment syntaxes:
> 
>   /* ... */
>   // ... EOL
>   # ... EOL

Thanks Ted. Now I only wonder about that strange 
font-lock-syntactic-keywords spec that I can not find in the Emacs lisp 
manual.

Re: What is this syntax for in php-mode.el

[Robert D. Crawford]

"Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:

> Thanks Ted. Now I only wonder about that strange
> font-lock-syntactic-keywords spec that I can not find in the Emacs
> lisp manual.

This might help, fetched with apropos:

font-lock-syntactic-keywords is a variable defined in `font-lock.el'.
Its value is nil


Documentation:
A list of the syntactic keywords to put syntax properties on.
The value can be the list itself, or the name of a function or variable
whose value is the list.

See `font-lock-keywords' for a description of the form of this list;
only the differences are stated here.  MATCH-HIGHLIGHT should be of the form:

 (SUBEXP SYNTAX OVERRIDE LAXMATCH)

where SYNTAX can be a string (as taken by `modify-syntax-entry'), a syntax
table, a cons cell (as returned by `string-to-syntax') or an expression whose
value is such a form.  OVERRIDE cannot be `prepend' or `append'.

Here are two examples of elements of `font-lock-syntactic-keywords'
and what they do:

 ("\\$\\(#\\)" 1 ".")

 gives a hash character punctuation syntax (".") when following a
 dollar-sign character.  Hash characters in other contexts will still
 follow whatever the syntax table says about the hash character.

 ("\\('\\).\\('\\)"
  (1 "\"")
  (2 "\""))

 gives a pair single-quotes, which surround a single character, a SYNTAX of
 "\"" (meaning string quote syntax).  Single-quote characters in other
 contexts will not be affected.

This is normally set via `font-lock-defaults'.


-- 
Robert D. Crawford                                      rdc1x@comcast.net

This fortune was brought to you by the people at Hewlett-Packard.

Re: What is this syntax for in php-mode.el

[Lennart Borgman (gmail)]

Robert D. Crawford wrote:
> "Lennart Borgman (gmail)" <lennart.borgman@gmail.com> writes:
> 
>> Thanks Ted. Now I only wonder about that strange
>> font-lock-syntactic-keywords spec that I can not find in the Emacs
>> lisp manual.
> 
> This might help, fetched with apropos:
> 
> font-lock-syntactic-keywords is a variable defined in `font-lock.el'.
> Its value is nil
> 
> 
> Documentation:
> A list of the syntactic keywords to put syntax properties on.
> The value can be the list itself, or the name of a function or variable
> whose value is the list.
> 
> See `font-lock-keywords' for a description of the form of this list;
> only the differences are stated here.  MATCH-HIGHLIGHT should be of the form:
> 
>  (SUBEXP SYNTAX OVERRIDE LAXMATCH)
> 
> where SYNTAX can be a string (as taken by `modify-syntax-entry'), a syntax
> table, a cons cell (as returned by `string-to-syntax') or an expression whose
> value is such a form.  OVERRIDE cannot be `prepend' or `append'.
> 
> Here are two examples of elements of `font-lock-syntactic-keywords'
> and what they do:
> 
>  ("\\$\\(#\\)" 1 ".")
> 
>  gives a hash character punctuation syntax (".") when following a
>  dollar-sign character.  Hash characters in other contexts will still
>  follow whatever the syntax table says about the hash character.
> 
>  ("\\('\\).\\('\\)"
>   (1 "\"")
>   (2 "\""))
> 
>  gives a pair single-quotes, which surround a single character, a SYNTAX of
>  "\"" (meaning string quote syntax).  Single-quote characters in other
>  contexts will not be affected.
> 
> This is normally set via `font-lock-defaults'.


Maybe. My trouble is that I can not fit something like the below into 
this format:

     (list
      ;; Mark _all_ # chars as being comment-start.  That will be
      ;; ignored when inside a quoted string.
      '("\\(\#\\)"
        (1 (11 . nil)))
      ;; Mark all newlines ending a line with # as being comment-end.
      ;; This causes a problem, premature end-of-comment, when '#'
      ;; appears inside a multiline C-style comment.  Oh well.
      '("#.*?\\([\n]\\)"
        (1 (12 . nil)))

This code works except for trouble of the kind noted in the comment. I 
am trying to understand if there is any way around this problem.

Re: What is this syntax for in php-mode.el

[Stefan Monnier]

> I am looking at php-mode.el from Turadg. I can not understand this:

> (defconst php-font-lock-syntactic-keywords
>   (if xemacsp nil
>     ;; Mark shell-style comments.  font-lock handles this in a
>     ;; separate pass from normal syntactic scanning (somehow), so we
>     ;; get a chance to mark these in addition to C and C++ style
>     ;; comments.  This only works in GNU Emacs, not XEmacs 21 which
>     ;; seems to ignore this same code if we try to use it.
>     (list
>      ;; Mark _all_ # chars as being comment-start.  That will be
>      ;; ignored when inside a quoted string.
>      '("\\(\#\\)"
>        (1 (11 . nil)))
>      ;; Mark all newlines ending a line with # as being comment-end.
>      ;; This causes a problem, premature end-of-comment, when '#'
>      ;; appears inside a multiline C-style comment.  Oh well.
>      '("#.*\\([\n]\\)"
>        (1 (12 . nil)))
>      )))

> What is it for? Does php use # as a comment somewhere?

> And what about the format for the list entries? I tried to look at
> font-lock-syntactic-keywords, but I can not see that these entries follows
> the spec there.

> How does this work?

Please tell the author that he doesn't need this gymnastics.
Just set # to comment-starter in the syntax-table and be done with it.
Make sure it has the comment-style (a or b) corresponding to the one of \n
(presumably it's b, if I read the problem-comment above correctly):

    (modify-syntax-entry ?# "< b" php-mode-syntax-table)


-- Stefan

Re: What is this syntax for in php-mode.el

[Lennart Borgman (gmail)]

Stefan Monnier wrote:

> Please tell the author that he doesn't need this gymnastics.
> Just set # to comment-starter in the syntax-table and be done with it.
> Make sure it has the comment-style (a or b) corresponding to the one of \n
> (presumably it's b, if I read the problem-comment above correctly):
> 
>     (modify-syntax-entry ?# "< b" php-mode-syntax-table)


But as Ted pointed out before PHP has 3 comment styles, the two from 
C/C++ and then the shell comment style above. Is it really possible to 
handle this with the syntax table?

Re: What is this syntax for in php-mode.el

[Lennart Borgman (gmail)]

Lennart Borgman (gmail) wrote:
> Stefan Monnier wrote:
> 
>> Please tell the author that he doesn't need this gymnastics.
>> Just set # to comment-starter in the syntax-table and be done with it.
>> Make sure it has the comment-style (a or b) corresponding to the one 
>> of \n
>> (presumably it's b, if I read the problem-comment above correctly):
>>
>>     (modify-syntax-entry ?# "< b" php-mode-syntax-table)
> 
> 
> But as Ted pointed out before PHP has 3 comment styles, the two from 
> C/C++ and then the shell comment style above. Is it really possible to 
> handle this with the syntax table?


And maybe I should have tested first ...

Thanks Stefan, it works.