master aabf144d: Arrange indent of tabular-like environments (bug#65648)

[Ikumi Keita]

branch: master
commit aabf144dfb5c2ce4a2de37f45d88b0fadf77a57a
Author: Ikumi Keita <ikumi@ikumi.que.jp>
Commit: Ikumi Keita <ikumi@ikumi.que.jp>

    Arrange indent of tabular-like environments (bug#65648)
    
    This fixes bug#54949 as well.
    
    * latex.el (LaTeX-env-beginning-pos-indent): New function to align "&"
    and \end{foo} relative to the indent of the line where \begin{foo} is,
    not the column of \begin{foo} itself.
    (LaTeX-indent-tabular, LaTeX-hanging-ampersand-position): Use the new
    function instead of `LaTeX-env-beginning-pos-col'.  This makes
    difference when \begin{foo} isn't on its own dedicated line.
    (LaTeX-hanging-ampersand-position): Arrange the doc string.
    * tests/latex/tabular-out.tex: Modify the expected result according to
    the above change.
---
 latex.el                    | 24 +++++++++++++++++++-----
 tests/latex/tabular-out.tex |  8 ++++----
 2 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/latex.el b/latex.el
index 548b18a9..3abb00f2 100644
--- a/latex.el
+++ b/latex.el
@@ -8911,22 +8911,36 @@ function would return non-nil and `(match-string 1)' 
would return
             (replace-match "\\\\input{" nil nil)))))
   (TeX-normal-mode nil))
 
+;; This function is no longer used; We leave it for compatibility.
 (defun LaTeX-env-beginning-pos-col ()
   "Return a cons: (POINT . COLUMN) for current environment's beginning."
   (save-excursion
     (LaTeX-find-matching-begin)
     (cons (point) (current-column))))
 
+;; This makes difference from `LaTeX-env-beginning-pos-col' when
+;; something non-whitespace sits before the \begin{foo}.  (bug#65648)
+(defun LaTeX-env-beginning-pos-indent ()
+  "Return a cons: (POINT . INDENT) for current environment's beginning.
+INDENT is the indent of the line containing POINT."
+  (save-excursion
+    ;; FIXME: There should be some fallback mechanism in case that the
+    ;; next `backward-up' fails.  (Such fail can occur in document
+    ;; with temporarily broken structure due to in-progress editing
+    ;; process.)
+    (LaTeX-backward-up-environment)
+    (cons (point) (LaTeX-current-indentation))))
+
 (defun LaTeX-hanging-ampersand-position (&optional pos col)
   "Return indent column for a hanging ampersand (that is, ^\\s-*&).
-When you know the position and column of the beginning of the
-current environment, supply them as optional arguments POS and
-COL for efficiency."
+When you know the position of the beginning of the current
+environment and indent of its line, supply them as optional
+arguments POS and COL for efficiency."
   (cl-destructuring-bind
       (beg-pos . beg-col)
       (if pos
           (cons pos col)
-        (LaTeX-env-beginning-pos-col))
+        (LaTeX-env-beginning-pos-indent))
     (let ((cur-pos (point)))
       (save-excursion
         (if (and (search-backward "\\\\" beg-pos t)
@@ -8957,7 +8971,7 @@ COL for efficiency."
   "Return indent column for the current tabular-like line."
   (cl-destructuring-bind
       (beg-pos . beg-col)
-      (LaTeX-env-beginning-pos-col)
+      (LaTeX-env-beginning-pos-indent)
     (let ((tabular-like-end-regex
            (format "\\\\end{%s}"
                    (regexp-opt
diff --git a/tests/latex/tabular-out.tex b/tests/latex/tabular-out.tex
index 66de0641..113c1d12 100644
--- a/tests/latex/tabular-out.tex
+++ b/tests/latex/tabular-out.tex
@@ -45,11 +45,11 @@
 \begin{equation}
   \begin{aligned}
     &n u m=\left[\begin{array}{ll}
-                   2 & 25
-                 \end{array}\right] \\
+      2 & 25
+    \end{array}\right] \\
     &d e n=\left[\begin{array}{lll}
-                   1 & 4 & 25
-                 \end{array}\right]
+      1 & 4 & 25
+    \end{array}\right]
   \end{aligned}
 \end{equation}