branch: elpa/rust-mode
commit 52317099f160869f37d9b02e279db4ab474c26a3
Author: Micah Chalmer <[email protected]>
Commit: Micah Chalmer <[email protected]>
Speed up calls to "looking-back"
---
rust-mode.el | 29 +++++++++++++++++++++++++----
1 file changed, 25 insertions(+), 4 deletions(-)
diff --git a/rust-mode.el b/rust-mode.el
index 193f672..05d8528 100644
--- a/rust-mode.el
+++ b/rust-mode.el
@@ -20,6 +20,27 @@
"Set variable VAR to value VAL in current buffer."
(list 'set (list 'make-local-variable (list 'quote var)) val))))
+(defun rust-looking-back-str (str)
+ "Like `looking-back' but for fixed strings rather than regexps (so that it's
not so slow)"
+ (let ((len (length str)))
+ (and (> (point) len)
+ (equal str (buffer-substring-no-properties (- (point) len)
(point))))))
+
+(defun rust-looking-back-symbols (SYMS)
+ "Return non-nil if the point is just after a complete symbol that is a
member of the list of strings SYMS"
+ (save-excursion
+ (let* ((pt-orig (point))
+ (beg-of-symbol (progn (forward-thing 'symbol -1) (point)))
+ (end-of-symbol (progn (forward-thing 'symbol 1) (point))))
+ (and
+ (= end-of-symbol pt-orig)
+ (member (buffer-substring-no-properties beg-of-symbol pt-orig) SYMS)))))
+
+(defun rust-looking-back-ident ()
+ "Non-nil if we are looking backwards at a valid rust identifier"
+ (let ((beg-of-symbol (save-excursion (forward-thing 'symbol -1) (point))))
+ (looking-back rust-re-ident beg-of-symbol)))
+
;; Syntax definitions and helpers
(defvar rust-mode-syntax-table
(let ((table (make-syntax-table)))
@@ -77,7 +98,7 @@
(defun rust-rewind-irrelevant ()
(let ((starting (point)))
(skip-chars-backward "[:space:]\n")
- (if (looking-back "\\*/" nil) (backward-char))
+ (if (rust-looking-back-str "*/") (backward-char))
(if (rust-in-str-or-cmnt)
(rust-rewind-past-str-cmnt))
(if (/= starting (point))
@@ -141,13 +162,13 @@
;;
((skip-dot-identifier
(lambda ()
- (when (looking-back (concat "\\." rust-re-ident) nil)
+ (when (and (rust-looking-back-ident) (save-excursion
(forward-thing 'symbol -1) (= ?. (char-before))))
(forward-thing 'symbol -1)
(backward-char)
(- (current-column) rust-indent-offset)))))
(cond
;; foo.bar(...)
- ((looking-back ")" nil)
+ ((rust-looking-back-str ")")
(backward-list 1)
(funcall skip-dot-identifier))
@@ -271,7 +292,7 @@
;; ..or if the previous line ends with any of these:
;; { ? : ( , ; [ }
;; then we are at the beginning of an expression, so
stay on the baseline...
- (looking-back "[(,:;?[{}]\\|[^|]|" nil)
+ (looking-back "[(,:;?[{}]\\|[^|]|" (- (point) 2))
;; or if the previous line is the end of an
attribute, stay at the baseline...
(progn
(rust-rewind-to-beginning-of-current-level-expr) (looking-at "#")))))
baseline
