[elpa] externals/easy-escape 8623aa9 18/27: Hide backslashes before '(', ')', and '|'

[ELPA Syncer]

branch: externals/easy-escape
commit 8623aa9d715fe7677ea24d7164ea6e4ecdb3e65b
Author: Clément Pit--Claudel <clement.pitclaudel@live.com>
Commit: Clément Pit--Claudel <clement.pitclaudel@live.com>

    Hide backslashes before '(', ')', and '|'
---
 README.md      | 18 ++----------
 easy-escape.el | 86 ++++++++++++++++++++++++++++++++++++++--------------------
 2 files changed, 60 insertions(+), 44 deletions(-)

diff --git a/README.md b/README.md
index f0c79cd..9214fae 100644
--- a/README.md
+++ b/README.md
@@ -2,26 +2,14 @@
 
 ![Easy-escape: before and after](img/easy-escape.png)
 
-`easy-escape-minor-mode` composes double backslashes (escape characters) into 
single backslashes, and highlights them to improve readability. The underlying 
buffer text is not modified.
+`easy-escape-minor-mode` uses syntax highlighting and composition to make 
ELisp regular expressions more readable.  More precisely, it hides double 
backslashes preceding regexp specials (`()|`), composes other double 
backslashes into single ones, and applies a special face to each. The 
underlying buffer text is not modified.
 
-The default is to use a single \ character instead of two, but the character 
used and its color can be customized using `easy-escape-face` and 
`easy-escape-character`.
-
-## Screenshots
-
-### Using a custom color
-
-![Easy-escape: before and after](img/easy-escape-other-color.png)
-
-### Using a custom character
-
-![Easy-escape: before and after](img/easy-escape-other-character.png)
+The default is to use a single \ character instead of two, and to hide 
backslashes preceding parentheses or `|`.  The escape character and its color 
can be customized using `easy-escape-face` and `easy-escape-character` (which 
see), and backslashes before `()|` can be shown by disabling 
`easy-escape-hide-escapes-before-delimiters`.
 
 ## Setup
 
 ### MELPA (preferred)
 
-This will be valid if the package gets accepted on MELPA:
-
 1. Setup [MELPA](http://melpa.org/#/getting-started) if you haven't yet
 
     In your `.emacs`, add these three lines:
@@ -34,7 +22,7 @@ This will be valid if the package gets accepted on MELPA:
 
 2. Install the package: `M-x package-install RET easy-escape RET`
 
-3. Enable `easy-escape-minor-mode` in lisp buffers:
+3. Enable `easy-escape-minor-mode` in Lisp buffers:
 
     ```elisp
     ;; Replace 'lisp-mode-hook with 'prog-mode-hook to enable everywhere
diff --git a/easy-escape.el b/easy-escape.el
index 9b1ca00..801b0f6 100644
--- a/easy-escape.el
+++ b/easy-escape.el
@@ -21,20 +21,25 @@
 
 ;;; Commentary:
 
-;; `easy-escape-minor-mode' composes double backslashes (escape characters) 
into
-;; single backslashes, and highlights them to improve readability.
+;; `easy-escape-minor-mode' uses syntax highlighting and composition to make 
ELisp regular
+;; expressions more readable.  More precisely, it hides double backslashes
+;; preceding regexp specials (`()|'), composes other double backslashes into
+;; single ones, and applies a special face to each.  The underlying buffer text
+;; is not modified.
 ;;
-;; For example, `easy-escape` displays "\\(?:\\_<\\\\newcommand\\_>\\s-*\\)?"
-;; as "\(?:\_<\\newcommand\_>\s-*\)?".  The underlying text is not modified.
+;; For example, `easy-escape` prettifies this:
+;;   "\\(?:\\_<\\\\newcommand\\_>\\s-*\\)?"
+;; into this (`^' indicates a different color):
+;;   "(?:\_<\\newcommand\_>\s-*)?".
+;;    ^                        ^
 ;;
-;; The default it to use a single \ character instead of two, but the character
-;; used and its color can be customized using `easy-escape-face' and
-;; `easy-escape-character' (which see).
+;; The default is to use a single \ character instead of two, and to hide
+;; backslashes preceding parentheses or `|'.  The escape character and its 
color
+;; can be customized using `easy-escape-face' and `easy-escape-character' 
(which see), and backslashes
+;; before ()| can be shown by disabling 
`easy-escape-hide-escapes-before-delimiters'.
 ;;
 ;; Suggested setup:
 ;;   (add-hook 'lisp-mode-hook 'easy-escape-minor-mode)
-;; or
-;;   (add-hook 'prog-mode-hook 'easy-escape-minor-mode)
 ;;
 ;; NOTE: If you find the distinction between the fontified double-slash and the
 ;; single slash too subtle, try the following:
@@ -55,6 +60,11 @@
   "Face used to highlight \\\\ in strings"
   :group 'easy-escape)
 
+(defface easy-escape-delimiter-face
+  '((t :weight bold :slant normal :inherit font-lock-warning-face))
+  "Face used to highlight groups and alternations in strings"
+  :group 'easy-escape)
+
 (defcustom easy-escape-character ?\\
   "Character by which \\\\ is replaced when `easy-escape-minor-mode' is active.
 Good candidates include the following:
@@ -68,31 +78,48 @@ Good candidates include the following:
   ⦥ MATHEMATICAL REVERSED ANGLE WITH UNDERBAR (typed as '?⦥')
   ⦣ MATHEMATICAL REVERSED ANGLE (typed as '?⦣')
   ⧹ BIG REVERSE SOLIDUS (typed as '?⧹')
-Most of these characters require non-standard fonts to display properly, 
however."
+Most of these characters require non-standard fonts to display properly,
+however."
   :group 'easy-escape)
 
-(defconst easy-escape--keywords
-  '((easy-escape--mark-escapes (0 (easy-escape--compose (match-beginning 0)))
-                               (0 'easy-escape-face append)))
-  "Font-lock keyword list used internally.")
+(defcustom easy-escape-hide-escapes-before-delimiters t
+  "Whether to hide \\\\ when it precedes one of `(', `|', and `)'."
+  :group 'easy-escape
+  :type 'boolean)
 
 (defun easy-escape--in-string-p (pos)
   "Indicate whether POS is inside of a string."
   (let ((face (get-text-property pos 'face)))
-    (or (eq 'font-lock-string-face face)
-        (and (listp face) (memq 'font-lock-string-face face)))))
+    (or (eq 'font-lock-doc-face face)
+        (eq 'font-lock-string-face face)
+        (and (listp face) (or (memq 'font-lock-doc-face face)
+                              (memq 'font-lock-string-face face))))))
 
-(defun easy-escape--mark-escapes (limit)
-  "Position point at end of next \\\\, and set match data.
-Search ends at LIMIT."
+(defun easy-escape--mark-in-string (re lim)
+  "Find next match for RE before LIM that falls in a string."
   (catch 'found
-    (while (re-search-forward "\\(\\\\\\\\\\)" limit t)
+    (while (re-search-forward re lim t)
       (when (easy-escape--in-string-p (match-beginning 0))
         (throw 'found t)))))
 
-(defun easy-escape--compose (start)
-  "Compose characters from START to (+ 2 START) into `easy-escape-character'."
-  (compose-region start (+ 2 start) easy-escape-character))
+(defun easy-escape--mark-escapes (limit)
+  "Search for \\\\ before LIMIT."
+  (easy-escape--mark-in-string "\\(\\\\\\\\\\)" limit))
+
+(defun easy-escape--mark-delims (limit)
+  "Search for a delimiter or alternation before LIMIT."
+  (easy-escape--mark-in-string "\\(\\\\\\\\\\)\\([()|]\\)" limit))
+
+(defun easy-escape--compose (n char)
+  "Compose match group N into CHAR."
+  (compose-region (match-beginning n) (match-end n) char))
+
+(defconst easy-escape--keywords
+  '((easy-escape--mark-escapes
+     (0 (progn (easy-escape--compose 0 easy-escape-character) 
'easy-escape-face) prepend))
+    (easy-escape--mark-delims
+     (0 (progn (easy-escape--compose 0 (char-after (match-beginning 2))) 
'easy-escape-delimiter-face) prepend)))
+  "Font-lock keyword list used internally.")
 
 ;;;###autoload
 (define-minor-mode easy-escape-minor-mode
@@ -108,12 +135,13 @@ and the single slash too subtle, try the following:
 * Set `easy-escape-character' to a different character."
   :lighter " ez-esc"
   :group 'easy-escape
-  (if easy-escape-minor-mode
-      (progn (font-lock-add-keywords nil easy-escape--keywords)
-             (add-to-list (make-local-variable 'font-lock-extra-managed-props) 
'composition))
-    (font-lock-remove-keywords nil easy-escape--keywords))
-  (if (>= emacs-major-version 25)
-      (font-lock-flush)
+  (cond
+   (easy-escape-minor-mode
+    (font-lock-add-keywords nil easy-escape--keywords)
+    (make-local-variable 'font-lock-extra-managed-props)
+    (add-to-list 'font-lock-extra-managed-props 'composition))
+   (t (font-lock-remove-keywords nil easy-escape--keywords)))
+  (if (>= emacs-major-version 25) (font-lock-flush)
     (with-no-warnings (font-lock-fontify-buffer))))
 
 (provide 'easy-escape)