If you want to make XEmacs faster, target your favorite slow benchmark,
run a profiler like Quantify, @code{gprof}, or @code{tcov}, and figure
-out where the cycles are going. Specific projects:
+out where the cycles are going. In many cases you can localize the
+problem (because a particular new feature or even a single patch
+elicited it). Don't hesitate to use brute force techniques like a
+global counter incremented at strategic places, especially in
+combination with other performance indications (@emph{e.g.}, degree of
+buffer fragmentation into extents).
+
+Specific projects:
@itemize @bullet
@item
@item
Speed up redisplay.
@item
-Speed up syntax highlighting. Maybe moving some of the syntax
-highlighting capabilities into C would make a difference.
+Speed up syntax highlighting. It was suggested that ``maybe moving some
+of the syntax highlighting capabilities into C would make a
+difference.'' Wrong idea, I think. When processing one large file a
+particular low-level routine was being called 40 @emph{million} times
+simply for @emph{one} call to @code{newline-and-indent}. Syntax
+highlighting needs to be rewritten to use a reliable, fast parser, then
+to trust the pre-parsed structure, and only do re-highlighting locally
+to a text change. Modern machines are fast enough to implement such
+parsers in Lisp; but no machine will ever be fast enough to deal with
+quadratic (or worse) algorithms!
@item
Implement tail recursion in Emacs Lisp (hard!).
@end itemize
@code{Check-Error}, @code{Check-Error-Message}, and @code{Check-Message}
macros.
+In general, you should avoid using functionality from packages in your
+tests, because you can't be sure that everyone will have the required
+package. However, if you've got a test that works, by all means add it.
+Simply wrap the test in an appropriate test, add a notice that the test
+was skipped, and update the @code{skipped-test-reasons} hashtable.
+Here's an example from @file{syntax-tests.el}:
+
+@example
+;; Test forward-comment at buffer boundaries
+(with-temp-buffer
+
+ ;; try to use exactly what you need: featurep, boundp, fboundp
+ (if (not (fboundp 'c-mode))
+
+ ;; We should provide a standard function for this boilerplate,
+ ;; probably called `Skip-Test' -- check for that API with C-h f
+ (let* ((reason "c-mode unavailable")
+ (count (gethash reason skipped-test-reasons)))
+ (puthash reason (if (null count) 1 (1+ count))
+ skipped-test-reasons)
+ (Print-Skip "comment and parse-partial-sexp tests" reason))
+
+ ;; and here's the test code
+ (c-mode)
+ (insert "// comment\n")
+ (forward-comment -2)
+ (Assert (eq (point) (point-min)))
+ (let ((point (point)))
+ (insert "/* comment */")
+ (goto-char point)
+ (forward-comment 2)
+ (Assert (eq (point) (point-max)))
+ (parse-partial-sexp point (point-max)))))
+@end example
+
+@code{Skip-Test} is intended for use with features that are normally
+present in typical configurations. For truly optional features, or
+tests that apply to one of several alternative implementations (eg, to
+GTK widgets, but not Athena, Motif, MS Windows, or Carbon), simply
+silently omit the test.
+
+
@node A Summary of the Various XEmacs Modules, Allocation of Objects in XEmacs Lisp, Regression Testing XEmacs, Top
@chapter A Summary of the Various XEmacs Modules
@cindex modules, a summary of the various XEmacs
@code{forward-sexp}, and by @file{font-lock.c} to locate quoted strings,
comments, etc.
+@c #### Break this out into a separate node somewhere!
+Syntax codes are implemented as bitfields in an int. Bits 0-6 contain
+the syntax code itself, bit 7 is a special prefix flag used for Lisp,
+and bits 16-23 contain comment syntax flags. From the Lisp programmer's
+point of view, there are 11 flags: 2 styles X 2 characters X @{start,
+end@} flags for two-character comment delimiters, 2 style flags for
+one-character comment delimiters, and the prefix flag.
+
+Internally, however, the characters used in multi-character delimiters
+will have non-comment-character syntax classes (@emph{e.g.}, the
+@samp{/} in C's @samp{/*} comment-start delimiter has ``punctuation''
+(here meaning ``operator-like'') class in C modes). Thus in a mixed
+comment style, such as C++'s @samp{//} to end of line, is represented by
+giving @samp{/} the ``punctuation'' class and the ``style b first
+character of start sequence'' and ``style b second character of start
+sequence'' flags. The fact that class is @emph{not} punctuation allows
+the syntax scanner to recognize that this is a multi-character
+delimiter. The @samp{newline} character is given (single-character)
+``comment-end'' @emph{class} and the ``style b first character of end
+sequence'' @emph{flag}. The ``comment-end'' class allows the scanner to
+determine that no second character is needed to terminate the comment.
@example
projects / chise / xemacs-chise.git.1 / blobdiff