[nongnu] elpa/go-mode 5186c83 491/495: Support basic indenting in multiline comments.

[ELPA Syncer]

branch: elpa/go-mode
commit 5186c83e5691932d208fafedf9a1a5ade369eb24
Author: Muir Manders <muir@mnd.rs>
Commit: Peter Sanford <psanford@sanford.io>

    Support basic indenting in multiline comments.
    
    This commit changes a few things to get indenting working in multiline
    comments:
    
    1. Make go-indentation-at-point return something when inside multiline
       comments. It basically guesses an indent based on the previous line
       or start of comment, along with a special case to line up all the
       "*" if you are making comment art. I didn't think it was worth it
       to support all of gofmt's multiline comment behavior.
    
    2. Don't ignore comments in go-mode-indent-line.
    
    3. Tweak go-mode-indent-line to not uses tabs when indenting beyond
       the "/*" in multiline comments. If you use tabs, gofmt ends up
       changing things around in unexpected ways.
    
    4. Tweak our electric indent function to trigger completion after
       newline within comments, and after typing the closing "*/".
    
    Fixes #369.
    
    Closes: #370 [via git-merge-pr]
---
 go-mode.el                                         | 135 +++++++++++++++++----
 test/go-indentation-test.el                        |  73 +++++++++++
 .../indentation_tests/multiline_comment.go         |  43 +++++++
 3 files changed, 230 insertions(+), 21 deletions(-)

diff --git a/go-mode.el b/go-mode.el
index 835dc18..21719a9 100644
--- a/go-mode.el
+++ b/go-mode.el
@@ -873,7 +873,80 @@ The return value is the position of the opening paren."
        (point)))))
 
 (defun go-indentation-at-point ()
-  "Return the appropriate indentation for the current line.
+  "Return the appropriate indentation for the current line."
+  (save-excursion
+    (beginning-of-line)
+
+    (if (go-in-comment-p)
+        (go--multiline-comment-indent)
+      (go--indentation-at-point))))
+
+(defun go--multiline-comment-indent ()
+  "Return the appropriate indent inside multiline comment.
+
+Assumes point is at beginning of line within comment. This
+function has basic logic to indent as you add new lines to a
+multiline comment, and to line up all the `*' if each line starts
+with `*'. The gofmt behavior for multiline comments is
+suprisingly complex and strange/buggy, so we just aim to do
+something simple rather than encode all the subtle behavior."
+  (let* (;; Indent of current line.
+         (indent (current-indentation))
+         ;; Indent of opening "/*".
+         start-indent
+         ;; Default indent to use based on preceding context.
+         natural-indent
+         ;; Non-nil means keep existing indent and give up calculating indent.
+         give-up
+         ;; Whether all comment lines (except first) begin with "*".
+         (all-star t))
+
+    (save-excursion
+      (go-goto-beginning-of-string-or-comment)
+
+      (setq start-indent (current-indentation))
+
+      ;; If other stuff precedes start of multiline comment, give up.
+      (setq give-up (/= (current-column) start-indent))
+
+      ;; Skip "/*".
+      (forward-char 2)
+
+      (skip-syntax-forward " ")
+
+      (if (not (eolp))
+          ;; If we aren't at EOL, we have content on the first line.
+          ;; Base our natural indent on that.
+          (setq natural-indent (current-column))
+        ;; Otherwise default to 1 space beyond "/*".
+        (setq natural-indent (+ start-indent 3)))
+
+      (let (done)
+        (while (not done)
+          (setq done (or (looking-at ".*\\*/") (not (zerop (forward-line)))))
+          (setq all-star (and all-star (looking-at "[[:space:]]*\\*"))))))
+
+    ;; If previous line has comment content, use its indent as our
+    ;; natural indent.
+    (save-excursion
+      (when (zerop (forward-line -1))
+        (beginning-of-line)
+        (when (and (go-in-comment-p) (> (current-indentation) 0))
+          (setq natural-indent (current-indentation)))))
+
+    (cond
+     (give-up indent)
+
+     (all-star (1+ start-indent))
+
+     ;; Closing "*/" with no preceding content always lines up with "/*".
+     ((looking-at "[[:space:]]*\\*/") start-indent)
+
+     ;; If the line is already indented, leave it.
+     (t (if (zerop indent) natural-indent indent)))))
+
+(defun go--indentation-at-point ()
+  "Return the appropriate indentation for the current non-comment line.
 
 This function works by walking a line's characters backwards. When it
 encounters a closing paren or brace it bounces to the corresponding
@@ -1242,14 +1315,14 @@ INDENT is the normal indent of this line, i.e. that of 
the case body."
 (defun go-mode-indent-line ()
   (interactive)
   (let (indent
-        shift-amt
         ;; case sensitively match "case", "default", etc.
         (case-fold-search nil)
         (pos (- (point-max) (point)))
         (point (point))
-        (beg (line-beginning-position)))
+        (beg (line-beginning-position))
+        (non-tab-indents 0))
     (back-to-indentation)
-    (if (go-in-string-or-comment-p)
+    (if (go-in-string-p)
         (goto-char point)
       (setq indent (go-indentation-at-point))
       (when (or
@@ -1263,11 +1336,22 @@ INDENT is the normal indent of this line, i.e. that of 
the case body."
              ;; comment attached above a "case" statement
              (go--case-comment-p indent))
         (cl-decf indent tab-width))
-      (setq shift-amt (- indent (current-column)))
-      (if (zerop shift-amt)
-          nil
+
+      ;; Don't do anything if current indent is correct.
+      (when (/= indent (current-column))
+        ;; Don't use tabs for indenting beyond "/*" in multiline
+        ;; comments. They don't play well with gofmt.
+        (when (go-in-comment-p)
+          (save-excursion
+            (go-goto-beginning-of-string-or-comment)
+            (when (> indent (current-indentation))
+              (setq non-tab-indents (- indent (current-indentation)))
+              (setq indent (current-indentation)))))
+
         (delete-region beg (point))
-        (indent-to indent))
+        (indent-to indent)
+        (insert-char ?  non-tab-indents))
+
       ;; If initial point was within line's indentation,
       ;; position after the indentation.  Else stay at same point in text.
       (if (> (- (point-max) pos) (point))
@@ -1692,19 +1776,28 @@ This is intended to be called from 
`before-change-functions'."
   (setq go-dangling-cache (make-hash-table :test 'eql)))
 
 (defun go--electric-indent-function (inserted-char)
-  (cond
-   ;; Indent after starting a "//" or "/*" comment.
-   ;; This is handy for comments above "case" statements.
-   ((or (eq inserted-char ?/) (eq inserted-char ?*))
-    (when (eq (char-before (1- (point))) ?/)
-      'do-indent))
-
-   ((eq inserted-char ? )
-    (and
-     (eq (char-before (- (point) 1)) ?e)
-     (eq (char-before (- (point) 2)) ?s)
-     (eq (char-before (- (point) 3)) ?a)
-     (eq (char-before (- (point) 4)) ?c)))))
+  (let ((prev (char-before (1- (point)))))
+    (cond
+     ;; Indent after starting/ending a comment. This is handy for
+     ;; comments above "case" statements and closing multiline
+     ;; comments.
+     ((or
+       (and (eq inserted-char ?/) (eq prev ?/))
+       (and (eq inserted-char ?/) (eq prev ?*))
+       (and (eq inserted-char ?*) (eq prev ?/)))
+      'do-indent)
+
+     ((eq inserted-char ? )
+      (and
+       (eq prev ?e)
+       (eq (char-before (- (point) 2)) ?s)
+       (eq (char-before (- (point) 3)) ?a)
+       (eq (char-before (- (point) 4)) ?c)))
+
+     ;; Trick electric-indent-mode into indenting inside multiline
+     ;; comments.
+     ((and (eq inserted-char ?\n) (go-in-comment-p))
+      'do-indent))))
 
 (defun go--comment-region (beg end &optional arg)
   "Switch to block comment when commenting a partial line."
diff --git a/test/go-indentation-test.el b/test/go-indentation-test.el
index 8ed95f7..8f5d9bc 100644
--- a/test/go-indentation-test.el
+++ b/test/go-indentation-test.el
@@ -49,3 +49,76 @@ var foo = 123 +
        789
 "
    ))
+
+(ert-deftest go--indent-multiline-comment ()
+  (go--should-indent
+   "
+{
+       /*
+a
+       */
+}
+"
+
+   "
+{
+       /*
+          a
+       */
+}
+")
+
+  (go--should-indent
+   "
+{
+       /*   LISTEN
+a
+       */
+}
+"
+
+   "
+{
+       /*   LISTEN
+            a
+       */
+}
+")
+
+  (go--should-indent
+   "
+{
+       /* c
+       c
+c
+       */
+}
+"
+
+   "
+{
+       /* c
+       c
+       c
+       */
+}
+")
+
+  (go--should-indent
+   "
+{
+       /* cool
+       *  cat
+        *
+       */
+}
+"
+
+   "
+{
+       /* cool
+        *  cat
+        *
+        */
+}
+"))
diff --git a/test/testdata/indentation_tests/multiline_comment.go 
b/test/testdata/indentation_tests/multiline_comment.go
index 002f60c..5ccdf7e 100644
--- a/test/testdata/indentation_tests/multiline_comment.go
+++ b/test/testdata/indentation_tests/multiline_comment.go
@@ -9,3 +9,46 @@ func main() {
                // code
        }
 }
+
+func _() {
+       /*   foo
+        * bar
+        */
+
+       /* abc
+       123
+          def
+            lol
+       */
+
+       /*
+          abc
+            - def
+       */
+
+       /*
+          hello
+       there */
+
+       /*
+          hello
+          there */
+
+       /*
+          foo
+       */
+
+       /*
+         foo
+       */
+
+       /*
+        foo
+       */
+
+       /* foo
+       asd
+   asd
+          asd
+       */
+}