POINT is the position of point within STRING.
The return value is a list of completions and may contain the base-size
in the last `cdr'."
+ (setq completion-lazy-hilit-fn nil)
;; FIXME: We need to additionally return the info needed for the
;; second part of completion-base-position.
(completion--nth-completion 2 string table pred point metadata))
than the latter (which has two \"holes\" and three
one-letter-long matches).")
+(defvar-local completion-lazy-hilit nil
+ "If non-nil, request completion lazy hilighting.
+
+Completion-presenting frontends may opt to bind this variable to
+non-nil value in the context of completion-producing calls (such
+as `completion-all-sorted-completions'). This hints the
+intervening completion styles that they do not need to propertize
+completion strings with the `face' property.
+
+When doing so, it is the frontend -- not the style -- who becomes
+responsible for `face'-propertizing only the completion strings
+that are meant to be displayed to the user. This is done by
+calling `completion-lazy-hilit' on each such string, which
+produces the suitably propertized string.
+
+Note that the optimization enabled by variable is only actually
+performed some completions styles. To others, it is a harmless
+and useless hint. To author a completion style that takes
+advantage of this, look in the source of
+`completion-pcm--hilit-commonality'.")
+
+(defvar completion-lazy-hilit-fn nil
+ "Used by completions styles to honouring `completion-lazy-hilit'.
+When a given style wants to enable support for
+`completion-lazy-hilit' (which see), that style should set this
+variable to a function of one argument, a fresh string to be
+displayed to the user. The function is responsible for
+destructively highlighting the string.")
+
+(defun completion-lazy-hilit (str)
+ "Return a copy of completion STR that is `face'-propertized.
+See documentation for variable `completion-lazy-hilit' for more
+details."
+ (if (and completion-lazy-hilit completion-lazy-hilit-fn)
+ (funcall completion-lazy-hilit-fn (copy-sequence str))
+ str))
+
+(defun completion--hilit-from-re (string regexp)
+ "Fontify STRING with `completions-common-part' using REGEXP."
+ (let* ((md (and regexp (string-match regexp string) (cddr (match-data t))))
+ (me (and md (match-end 0)))
+ (from 0))
+ (while md
+ (add-face-text-property from (pop md) 'completions-common-part nil string)
+ (setq from (pop md)))
+ (unless (or (not me) (= from me))
+ (add-face-text-property from me 'completions-common-part nil string))
+ string))
+
+(defun completion--flex-score-1 (md match-end len)
+ "Compute matching score of completion.
+The score lies in the range between 0 and 1, where 1 corresponds to
+the full match.
+MD is the match data.
+MATCH-END is the end of the match.
+LEN is the length of the completion string."
+ (let* ((from 0)
+ ;; To understand how this works, consider these simple
+ ;; ascii diagrams showing how the pattern "foo"
+ ;; flex-matches "fabrobazo", "fbarbazoo" and
+ ;; "barfoobaz":
+
+ ;; f abr o baz o
+ ;; + --- + --- +
+
+ ;; f barbaz oo
+ ;; + ------ ++
+
+ ;; bar foo baz
+ ;; +++
+
+ ;; "+" indicates parts where the pattern matched. A
+ ;; "hole" in the middle of the string is indicated by
+ ;; "-". Note that there are no "holes" near the edges
+ ;; of the string. The completion score is a number
+ ;; bound by (0..1] (i.e., larger than (but not equal
+ ;; to) zero, and smaller or equal to one): the higher
+ ;; the better and only a perfect match (pattern equals
+ ;; string) will have score 1. The formula takes the
+ ;; form of a quotient. For the numerator, we use the
+ ;; number of +, i.e. the length of the pattern. For
+ ;; the denominator, it first computes
+ ;;
+ ;; hole_i_contrib = 1 + (Li-1)^(1/tightness)
+ ;;
+ ;; , for each hole "i" of length "Li", where tightness
+ ;; is given by `flex-score-match-tightness'. The
+ ;; final value for the denominator is then given by:
+ ;;
+ ;; (SUM_across_i(hole_i_contrib) + 1) * len
+ ;;
+ ;; , where "len" is the string's length.
+ (score-numerator 0)
+ (score-denominator 0)
+ (last-b 0))
+ (while md
+ (let ((a from)
+ (b (pop md)))
+ (setq
+ score-numerator (+ score-numerator (- b a)))
+ (unless (or (= a last-b)
+ (zerop last-b)
+ (= a len))
+ (setq
+ score-denominator (+ score-denominator
+ 1
+ (expt (- a last-b 1)
+ (/ 1.0
+ flex-score-match-tightness)))))
+ (setq
+ last-b b))
+ (setq from (pop md)))
+ ;; If `pattern' doesn't have an explicit trailing any, the
+ ;; regex `re' won't produce match data representing the
+ ;; region after the match. We need to account to account
+ ;; for that extra bit of match (bug#42149).
+ (unless (= from match-end)
+ (let ((a from)
+ (b match-end))
+ (setq
+ score-numerator (+ score-numerator (- b a)))
+ (unless (or (= a last-b)
+ (zerop last-b)
+ (= a len))
+ (setq
+ score-denominator (+ score-denominator
+ 1
+ (expt (- a last-b 1)
+ (/ 1.0
+ flex-score-match-tightness)))))
+ (setq
+ last-b b)))
+ (/ score-numerator (* len (1+ score-denominator)) 1.0)))
+
(defun completion-pcm--hilit-commonality (pattern completions)
"Show where and how well PATTERN matches COMPLETIONS.
PATTERN, a list of symbols and strings as seen
`completion-pcm--merge-completions', is assumed to match every
-string in COMPLETIONS. Return a deep copy of COMPLETIONS where
-each string is propertized with `completion-score', a number
-between 0 and 1, and with faces `completions-common-part',
-`completions-first-difference' in the relevant segments."
+string in COMPLETIONS.
+
+If `completion-lazy-hilit' is nil, return a deep copy of
+COMPLETIONS where each string is propertized with
+`completion-score', a number between 0 and 1, and with faces
+`completions-common-part', `completions-first-difference' in the
+relevant segments.
+
+Else, if `completion-lazy-hilit' is t, return COMPLETIONS where
+each string now has a `completion-score' property and no
+highlighting."
(cond
((and completions (cl-loop for e in pattern thereis (stringp e)))
(let* ((re (completion-pcm--pattern->regex pattern 'group))
- (point-idx (completion-pcm--pattern-point-idx pattern))
- (case-fold-search completion-ignore-case)
- last-md)
- (mapcar
- (lambda (str)
- ;; Don't modify the string itself.
- (setq str (copy-sequence str))
- (unless (string-match re str)
- (error "Internal error: %s does not match %s" re str))
- (let* ((pos (if point-idx (match-beginning point-idx) (match-end 0)))
- (match-end (match-end 0))
- (md (cddr (setq last-md (match-data t last-md))))
- (from 0)
- (end (length str))
- ;; To understand how this works, consider these simple
- ;; ascii diagrams showing how the pattern "foo"
- ;; flex-matches "fabrobazo", "fbarbazoo" and
- ;; "barfoobaz":
-
- ;; f abr o baz o
- ;; + --- + --- +
-
- ;; f barbaz oo
- ;; + ------ ++
-
- ;; bar foo baz
- ;; +++
-
- ;; "+" indicates parts where the pattern matched. A
- ;; "hole" in the middle of the string is indicated by
- ;; "-". Note that there are no "holes" near the edges
- ;; of the string. The completion score is a number
- ;; bound by (0..1] (i.e., larger than (but not equal
- ;; to) zero, and smaller or equal to one): the higher
- ;; the better and only a perfect match (pattern equals
- ;; string) will have score 1. The formula takes the
- ;; form of a quotient. For the numerator, we use the
- ;; number of +, i.e. the length of the pattern. For
- ;; the denominator, it first computes
- ;;
- ;; hole_i_contrib = 1 + (Li-1)^(1/tightness)
- ;;
- ;; , for each hole "i" of length "Li", where tightness
- ;; is given by `flex-score-match-tightness'. The
- ;; final value for the denominator is then given by:
- ;;
- ;; (SUM_across_i(hole_i_contrib) + 1) * len
- ;;
- ;; , where "len" is the string's length.
- (score-numerator 0)
- (score-denominator 0)
- (last-b 0)
- (update-score-and-face
- (lambda (a b)
- "Update score and face given match range (A B)."
- (add-face-text-property a b
- 'completions-common-part
- nil str)
- (setq
- score-numerator (+ score-numerator (- b a)))
- (unless (or (= a last-b)
- (zerop last-b)
- (= a (length str)))
- (setq
- score-denominator (+ score-denominator
- 1
- (expt (- a last-b 1)
- (/ 1.0
- flex-score-match-tightness)))))
- (setq
- last-b b))))
- (while md
- (funcall update-score-and-face from (pop md))
- (setq from (pop md)))
- ;; If `pattern' doesn't have an explicit trailing any, the
- ;; regex `re' won't produce match data representing the
- ;; region after the match. We need to account to account
- ;; for that extra bit of match (bug#42149).
- (unless (= from match-end)
- (funcall update-score-and-face from match-end))
- (if (> (length str) pos)
- (add-face-text-property
- pos (1+ pos)
- 'completions-first-difference
- nil str))
- (unless (zerop (length str))
- (put-text-property
- 0 1 'completion-score
- (/ score-numerator (* end (1+ score-denominator)) 1.0) str)))
- str)
- completions)))
+ last-md
+ (score (lambda (str)
+ (unless (string-match re str)
+ (error "Internal error: %s does not match %s" re str))
+ (let* ((match-end (match-end 0))
+ (md (cddr (setq last-md (match-data t last-md)))))
+ (completion--flex-score-1 md match-end (length str))))))
+ (cond (completion-lazy-hilit
+ (setq completion-lazy-hilit-fn
+ (lambda (str) (completion--hilit-from-re str re)))
+ (mapc (lambda (str)
+ (put-text-property 0 1 'completion-score (funcall score str) str))
+ completions))
+ (t
+ (mapcar
+ (lambda (str)
+ (setq str (copy-sequence str))
+ (put-text-property 0 1 'completion-score (funcall score str) str)
+ (completion--hilit-from-re str re)
+ str)
+ completions)))))
(t completions)))
(defun completion-pcm--find-all-completions (string table pred point
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