HELP, PLEASE! Syntax problem!

[Aidan Kehoe]

 Ar an seachtú lá is fiche de mí na Samhain, scríobh Aidan Kehoe: 

 >  Ar an seachtú lá is fiche de mí na Samhain, scríobh Alan Mackenzie: 
 > 
 >  > On Fri, Nov 27, 2009 at 10:56:34AM +0100, David Kastrup wrote:
 >  >
 >  > > You are underestimating XEmacs.  It has a function iterating over all
 >  > > extents (their equivalent of both overlays and text properties) in a
 >  > > half-/open/closed range that have a particular set or state of
 >  > > properties.  So you can say something like "give me all extents for
 >  > > which the property 'category happens to be 'text".
 >  > 
 >  > > Something like
 >  > > (map-extents (lambda (extent) ...) some-flag (point-min)
 >  > >              (point-max) another-flag and-yet-another 'category 'text)
 >  > 
 >  > Yes, I've underestimated XEmacs.  But that map-extents is still
 >  > hopelessly slow by 2(?) orders of magnitude.  I need to "switch off
 >  > macros" each time I call `c-parse-state'.  In Emacs, I comment them out
 >  > with exactly this form:
 >  > 
 >  >    (put 'c-cpp-delimiter 'syntax-table '(14)) ; 14 is "generic comment".
 >  > 
 >  > The rogue file I'm making this change for has 4131 #defines in it.
 >  > map-extents would be hopeless for this out-commenting.
 > 
 > I’m not sure exactly what you’re doing in XEmacs, but is there anything
 > stopping you keeping the list representing the syntax table for
 > c-cpp-delimiters around (using it on creation of each such extent) and
 > modifying and reverting its car every time you want to do this? The
 > ‘inherit’ value (13, as it happens) should be sufficient to have it take its
 > syntax table from the surrounding text, if that’s what you want. So, 
 > 
 > (defvar c-cpp-delimiter-syntax-table '(13))
 > 
 > (put-text-property START END 'category 'text)
 > (put-text-property START END 'syntax-table c-cpp-delimiter-syntax-table)
 > 
 > (setcar c-cpp-delimiter-syntax-table 14) ;; on entry to c-parse-state
 > (setcar c-cpp-delimiter-syntax-table 13) ;; on exit from c-parse-state
 > 
 > Now, it’s probably foolhardy of me to suggest this without having tested it
 > (maybe the syntax-table property is broken ...) but in my defence, I can’t
 > find your code online. 

Looks like one would need to invalidate the syntax cache with that approach,
though. So something like: 

(defmacro c-set-cpp-delimiter-syntax-generic-comment (from to)
  (if (featurep 'xemacs)
      `(symbol-macrolet
	  ((generic-comment-syntax 14)) ;; A lot easier to grep for
	(setcar c-cpp-delimiter-syntax-table generic-comment-syntax)
	(map-extents #'(lambda (extent maparg)
			 ;; Force invalidation of the syntax cache:
			 (set-extent-property extent 'syntax-table nil)
			 (set-extent-property extent 'syntax-table
					      c-cpp-delimiter-syntax-table)
			 t) ; give up after the first extent
		     nil ,from ,to nil 'syntax-table
		     c-cpp-delimiter-syntax-table))
    `(put 'c-cpp-delimiter 'syntax-table '(14))))

(defmacro c-set-cpp-delimiter-syntax-inherit (from to)
  (if (featurep 'xemacs)
      `(symbol-macrolet
	  ((inherit-syntax 13))
	(setcar c-cpp-delimiter-syntax-table inherit-syntax)
	(map-extents #'(lambda (extent maparg)
			 ;; Force invalidation of the syntax cache:
			 (set-extent-property extent 'syntax-table nil)
			 (set-extent-property extent 'syntax-table
					      c-cpp-delimiter-syntax-table)
			 t) ; give up after the first extent
		     nil ,from ,to nil 'syntax-table
		     c-cpp-delimiter-syntax-table))
    `(put 'c-cpp-delimiter 'syntax-table '(14))))

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