Commit 00b80c6c authored by Christophe Rhodes's avatar Christophe Rhodes

Implement incremental lexing.

The contract is that

* UPDATE-SYNTAX notes the latest possible position that is known to be valid.

* UPDATE-SYNTAX-FOR-DISPLAY, within the display bounds, attempts to revalidate
  the previous lex if possible, or relex if not.  After
  UPDATE-SYNTAX-FOR-DISPLAY has finished, the entirety of the remaining
  lexemes are known valid (all the rest have been deleted).

This may be wrong: it may be that, since lexing takes essentially no time
at all, the whole buffer should be relexed each time.
parent e535a0d4
......@@ -148,7 +148,7 @@
(make-instance 'layout-text :cont nil))
(defclass prolog-lexer (incremental-lexer)
((valid-lex :initarg :valid-lex :accessor valid-lex :initform 1)))
((valid-lex :initarg :valid-lex :initform 1)))
(defmethod next-lexeme ((lexer prolog-lexer) scan)
(let ((string (make-array 0 :element-type 'character
......@@ -852,21 +852,26 @@
(defmethod update-syntax-for-display (buffer (syntax prolog-syntax) top bot)
(with-slots (parser lexer valid-parse) syntax
(with-slots (climacs-syntax::lexemes valid-lex) lexer
(let ((scan (clone-mark (low-mark buffer) :left)))
(let ((scan (clone-mark (low-mark buffer) :left))
(high-mark (high-mark buffer)))
(setf (offset scan)
(end-offset (lexeme lexer (1- valid-lex))))
;; lex as far as we need. We actually win quite a lot if we
;; can implement the splicing described in the FIXME note,
;; below, because there's then a good chance that CLIM's
;; incremental redisplay will Do The Right Thing (on the EQ
;; lexemes)
(loop do (skip-inter-lexeme-objects lexer scan)
(loop named relex
do (skip-inter-lexeme-objects lexer scan)
until (end-of-buffer-p scan)
until (mark<= bot (start-offset (lexeme lexer (1- valid-lex))))
;; FIXME: a further criterion is when scan matches the
;; start-offset of an element in lexemes, at which point
;; we know that the entirety of the rest of the old lex
;; is valid without doing any further work.
do (when (mark>= scan high-mark)
(do ()
((= (nb-lexemes lexer) valid-lex))
(let ((l (lexeme lexer i)))
(cond
((mark< scan (start-offset l))
(return nil))
((mark= scan (start-offset l))
(setf valid-lex (nb-lexemes lexer))
(return-from relex))
(t
(delete* climacs-syntax::lexemes valid-lex))))))
do (let* ((start-mark (clone-mark scan))
(lexeme (next-lexeme lexer scan))
(size (- (offset scan) (offset start-mark))))
......@@ -874,16 +879,18 @@
(slot-value lexeme 'climacs-syntax::size) size)
(insert-lexeme lexer valid-lex lexeme)
(incf valid-lex)))
;; remove lexemes which we know to be invalid
(let ((end (end-offset (lexeme lexer (1- valid-lex)))))
(loop until (= (nb-lexemes lexer) valid-lex)
while (< (start-offset (lexeme lexer valid-lex)) end)
do (delete* climacs-syntax::lexemes valid-lex))))
;; remove lexemes which we know to be invalid.
;;
;; If we wanted some additional complexity, we could maintain
;; the possibility of not matching a start lexeme in the
;; visible region, but possibly elsewhere instead; however,
;; for now, simply assume that the VALID-LEX from above is
;; definitive.
(loop until (= (nb-lexemes lexer) valid-lex)
do (delete* climacs-syntax::lexemes valid-lex)))
;; parse up to the limit of validity imposed by the lexer, or
;; the bottom of the visible area
;; the bottom of the visible area, whichever comes sooner
(loop until (= valid-parse valid-lex)
;; NOTE: this ceases being the same condition as the above
;; as soon as the FIXME note above is implemented.
until (mark<= bot (start-offset (lexeme lexer (1- valid-parse))))
do (let ((current-token (lexeme lexer (1- valid-parse)))
(next-lexeme (lexeme lexer valid-parse)))
......@@ -900,7 +907,8 @@
(let* ((low-mark (low-mark buffer))
(high-mark (high-mark buffer)))
(when (mark<= low-mark high-mark)
(with-slots (climacs-syntax::lexemes valid-lex) lexer
(with-slots (climacs-syntax::lexemes valid-lex)
lexer
(let ((start 1)
(end (nb-elements climacs-syntax::lexemes)))
(loop while (< start end)
......
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