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[Emacs-diffs] master 5023908 5/5: Add chained indentation to js-mode
From: |
Tom Tromey |
Subject: |
[Emacs-diffs] master 5023908 5/5: Add chained indentation to js-mode |
Date: |
Fri, 13 Jan 2017 19:51:00 +0000 (UTC) |
branch: master
commit 502390822f9c0068898ae41285b37568bf0e4d1c
Author: Tom Tromey <address@hidden>
Commit: Tom Tromey <address@hidden>
Add chained indentation to js-mode
Bug#20896
* lisp/progmodes/js.el (js-chain-indent): New variable.
(js--skip-term-backward, js--skip-terms-backward)
(js--chained-expression-p): New functions.
(js--proper-indentation): Call js--chained-expression-p.
* test/manual/indent/js-chain.js: New file.
* test/manual/indent/js.js: Add (non-)chained indentation test.
---
lisp/progmodes/js.el | 72 ++++++++++++++++++++++++++++++++++++++++
test/manual/indent/js-chain.js | 29 ++++++++++++++++
test/manual/indent/js.js | 4 +++
3 files changed, 105 insertions(+)
diff --git a/lisp/progmodes/js.el b/lisp/progmodes/js.el
index e84215d..54df391 100644
--- a/lisp/progmodes/js.el
+++ b/lisp/progmodes/js.el
@@ -552,6 +552,20 @@ don't indent the first one's initializer; otherwise,
indent it.
:safe 'symbolp
:group 'js)
+(defcustom js-chain-indent nil
+ "Use \"chained\" indentation.
+Chained indentation applies when the current line starts with \".\".
+If the previous expression also contains a \".\" at the same level,
+then the \".\"s will be lined up:
+
+ let x = svg.mumble()
+ .chained;
+"
+ :version "26.1"
+ :type 'boolean
+ :safe 'booleanp
+ :group 'js)
+
;;; KeyMap
(defvar js-mode-map
@@ -1808,6 +1822,63 @@ This performs fontification according to
`js--class-styles'."
(and (progn (backward-char)
(not (looking-at "+\\+\\|--\\|/[/*]"))))))))))
+(defun js--skip-term-backward ()
+ "Skip a term before point; return t if a term was skipped."
+ (let ((term-skipped nil))
+ ;; Skip backward over balanced parens.
+ (let ((progress t))
+ (while progress
+ (setq progress nil)
+ ;; First skip whitespace.
+ (skip-syntax-backward " ")
+ ;; Now if we're looking at closing paren, skip to the opener.
+ ;; This doesn't strictly follow JS syntax, in that we might
+ ;; skip something nonsensical like "()[]{}", but it is enough
+ ;; if it works ok for valid input.
+ (when (memq (char-before) '(?\] ?\) ?\}))
+ (setq progress t term-skipped t)
+ (backward-list))))
+ ;; Maybe skip over a symbol.
+ (let ((save-point (point)))
+ (if (and (< (skip-syntax-backward "w_") 0)
+ (looking-at js--name-re))
+ ;; Skipped.
+ (progn
+ (setq term-skipped t)
+ (skip-syntax-backward " "))
+ ;; Did not skip, so restore point.
+ (goto-char save-point)))
+ (when (and term-skipped (> (point) (point-min)))
+ (backward-char)
+ (eq (char-after) ?.))))
+
+(defun js--skip-terms-backward ()
+ "Skip any number of terms backward.
+Move point to the earliest \".\" without changing paren levels.
+Returns t if successful, nil if no term was found."
+ (when (js--skip-term-backward)
+ ;; Found at least one.
+ (let ((last-point (point)))
+ (while (js--skip-term-backward)
+ (setq last-point (point)))
+ (goto-char last-point)
+ t)))
+
+(defun js--chained-expression-p ()
+ "A helper for js--proper-indentation that handles chained expressions.
+A chained expression is when the current line starts with '.' and the
+previous line also has a '.' expression.
+This function returns the indentation for the current line if it is
+a chained expression line; otherwise nil.
+This should only be called while point is at the start of the line's content,
+as determined by `back-to-indentation'."
+ (when js-chain-indent
+ (save-excursion
+ (when (and (eq (char-after) ?.)
+ (js--continued-expression-p)
+ (js--find-newline-backward)
+ (js--skip-terms-backward))
+ (current-column)))))
(defun js--end-of-do-while-loop-p ()
"Return non-nil if point is on the \"while\" of a do-while statement.
@@ -1984,6 +2055,7 @@ indentation is aligned to that column."
;; At or after the first loop?
(>= (point) beg)
(js--array-comp-indentation bracket beg))))
+ ((js--chained-expression-p))
((js--ctrl-statement-indentation))
((js--multi-line-declaration-indentation))
((nth 1 parse-status)
diff --git a/test/manual/indent/js-chain.js b/test/manual/indent/js-chain.js
new file mode 100644
index 0000000..2a29029
--- /dev/null
+++ b/test/manual/indent/js-chain.js
@@ -0,0 +1,29 @@
+// Normal chaining.
+let x = svg.mumble()
+ .zzz;
+
+// Chaining with an intervening line comment.
+let x = svg.mumble() // line comment
+ .zzz;
+
+// Chaining with multiple dots.
+let x = svg.selectAll().something()
+ .zzz;
+
+// Nested chaining.
+let x = svg.selectAll(d3.svg.something()
+ .zzz);
+
+// Nothing to chain to.
+let x = svg()
+ .zzz;
+
+// Nothing to chain to.
+let x = svg().mumble.x() + 73
+ .zzz;
+
+// Local Variables:
+// indent-tabs-mode: nil
+// js-chain-indent: t
+// js-indent-level: 2
+// End:
diff --git a/test/manual/indent/js.js b/test/manual/indent/js.js
index d004b82..846c3a1 100644
--- a/test/manual/indent/js.js
+++ b/test/manual/indent/js.js
@@ -124,6 +124,10 @@ if (x > 72 &&
do_something();
}
+// Test that chaining doesn't happen when js-chain-indent is nil.
+let x = svg.mumble()
+ .zzz;
+
// Local Variables:
// indent-tabs-mode: nil
// js-indent-level: 2