[Emacs-diffs] emacs-26 fc56bea: Correctly indent C++14 brace lists which are a second argument to a function.

[Alan Mackenzie]

branch: emacs-26
commit fc56bea1420266ea6495a2e74df28349458b6fb0
Author: Alan Mackenzie <address@hidden>
Commit: Alan Mackenzie <address@hidden>

    Correctly indent C++14 brace lists which are a second argument to a 
function.
    
    In particular, don't indent contained brace lists in "staircase" fashion.
    This fixes bug #28623.
    
    * lisp/progmodes/cc-engine.el (c-looking-at-or-maybe-in-bracelist): When
    testing for being enclosed in parens, recognise also a brace directly
    following a comma, as well as a brace being the first thing inside the 
paren.
    Enhance the return value, by indicating when we're directly inside an open
    paren.
    (c-inside-bracelist-p): Add an extra argument ACCEPT-IN-PARAM which 
indicates
    whether we will accept a bracelist directly inside an open parenthesis.
    Simplify the manipulation of PAREN-STATE by dispensing with variable LIM and
    using c-pull-open-brace.  Enhance the return value, respecting the new 
argument.
    (c-guess-basic-syntax): Save a copy of the initial parse-state in the new
    variable STATE-CACHE.  Use this variable in place of C-STATE-CACHE 
throughout
    the function.  At CASE 7B, call c-inside-bracelist-p with extra argument 
nil.
    At CASE 9, call that function with extra argument t.
---
 lisp/progmodes/cc-engine.el | 105 ++++++++++++++++++++++++--------------------
 1 file changed, 58 insertions(+), 47 deletions(-)

diff --git a/lisp/progmodes/cc-engine.el b/lisp/progmodes/cc-engine.el
index 6f39cc6..982be3b 100644
--- a/lisp/progmodes/cc-engine.el
+++ b/lisp/progmodes/cc-engine.el
@@ -10407,16 +10407,20 @@ comment at the start of cc-engine.el for more info."
 (defun c-looking-at-or-maybe-in-bracelist (&optional containing-sexp lim)
   ;; Point is at an open brace.  If this starts a brace list, return a list
   ;; whose car is the buffer position of the start of the construct which
-  ;; introduces the list, and whose cdr is t if we have parsed a keyword
-  ;; matching `c-opt-inexpr-brace-list-key' (e.g. Java's "new"), nil
-  ;; otherwise.  Otherwise, if point might be inside an enclosing brace list,
-  ;; return t.  If point is definitely neither at nor in a brace list, return
-  ;; nil.
+  ;; introduces the list, and whose cdr is the symbol `in-paren' if the brace
+  ;; is directly enclosed in a parenthesis form (i.e. an arglist), t if we
+  ;; have parsed a keyword matching `c-opt-inexpr-brace-list-key' (e.g. Java's
+  ;; "new"), nil otherwise.  Otherwise, if point might be inside an enclosing
+  ;; brace list, return t.  If point is definitely neither at nor in a brace
+  ;; list, return nil.
   ;;
   ;; CONTAINING-SEXP is the position of the brace/paren/bracket enclosing
   ;; POINT, or nil if there is no such position, or we do not know it.  LIM is
   ;; a backward search limit.
   ;;
+  ;; The determination of whether the brace starts a brace list is solely by
+  ;; the context of the brace, not by its contents.
+  ;;
   ;; Here, "brace list" does not include the body of an enum.
   (save-excursion
     (let ((start (point))
@@ -10426,17 +10430,20 @@ comment at the start of cc-engine.el for more info."
           (and (c-major-mode-is 'pike-mode)
                c-decl-block-key))
          (braceassignp 'dontknow)
-         inexpr-brace-list bufpos macro-start res pos after-type-id-pos)
+         inexpr-brace-list bufpos macro-start res pos after-type-id-pos
+         in-paren)
 
       (setq res (c-backward-token-2 1 t lim))
       ;; Checks to do only on the first sexp before the brace.
       ;; Have we a C++ initialization, without an "="?
       (if (and (c-major-mode-is 'c++-mode)
               (cond
-               ((and (not (eq res 0))
+               ((and (or (not (eq res 0))
+                         (eq (char-after) ?,))
                      (c-go-up-list-backward nil lim) ; FIXME!!! Check ; `lim' 
2016-07-12.
                      (eq (char-after) ?\())
-                (setq braceassignp 'c++-noassign))
+                (setq braceassignp 'c++-noassign
+                      in-paren 'in-paren))
                ((looking-at c-pre-id-bracelist-key))
                ((looking-at c-return-key))
                ((and (looking-at c-symbol-start)
@@ -10445,9 +10452,11 @@ comment at the start of cc-engine.el for more info."
                (t nil))
               (save-excursion
                 (cond
-                 ((not (eq res 0))
+                 ((or (not (eq res 0))
+                      (eq (char-after) ?,))
                   (and (c-go-up-list-backward nil lim) ; FIXME!!! Check `lim' 
2016-07-12.
-                       (eq (char-after) ?\()))
+                       (eq (char-after) ?\()
+                       (setq in-paren 'in-paren)))
                  ((looking-at c-pre-id-bracelist-key))
                  ((looking-at c-return-key))
                  (t (setq after-type-id-pos (point))
@@ -10486,7 +10495,7 @@ comment at the start of cc-engine.el for more info."
               (c-backward-syntactic-ws)
               (eq (char-before) ?\()))
        ;; Single identifier between '(' and '{'.  We have a bracelist.
-       (cons after-type-id-pos nil))
+       (cons after-type-id-pos 'in-paren))
 
        (t
        (goto-char pos)
@@ -10544,7 +10553,7 @@ comment at the start of cc-engine.el for more info."
         (braceassignp
          ;; We've hit the beginning of the aggregate list.
          (c-beginning-of-statement-1 containing-sexp)
-         (cons (point) inexpr-brace-list))
+         (cons (point) (or in-paren inexpr-brace-list)))
         ((and after-type-id-pos
               (save-excursion
                 (when (eq (char-after) ?\;)
@@ -10569,7 +10578,7 @@ comment at the start of cc-engine.el for more info."
                           nil nil))
                    (and (consp res)
                         (eq (car res) after-type-id-pos))))))
-         (cons bufpos inexpr-brace-list))
+         (cons bufpos (or in-paren inexpr-brace-list)))
         ((eq (char-after) ?\;)
          ;; Brace lists can't contain a semicolon, so we're done.
          ;; (setq containing-sexp nil)
@@ -10593,12 +10602,16 @@ comment at the start of cc-engine.el for more info."
         (t t))))                       ;; The caller can go up one level.
       )))
 
-(defun c-inside-bracelist-p (containing-sexp paren-state)
+(defun c-inside-bracelist-p (containing-sexp paren-state accept-in-paren)
   ;; return the buffer position of the beginning of the brace list
   ;; statement if we're inside a brace list, otherwise return nil.
   ;; CONTAINING-SEXP is the buffer pos of the innermost containing
   ;; paren.  PAREN-STATE is the remainder of the state of enclosing
-  ;; braces
+  ;; braces.  ACCEPT-IN-PAREN is non-nil iff we will accept as a brace
+  ;; list a brace directly enclosed in a parenthesis.
+  ;;
+  ;; The "brace list" here is recognized solely by its context, not by
+  ;; its contents.
   ;;
   ;; N.B.: This algorithm can potentially get confused by cpp macros
   ;; placed in inconvenient locations.  It's a trade-off we make for
@@ -10613,17 +10626,11 @@ comment at the start of cc-engine.el for more info."
    ;; this will pick up array/aggregate init lists, even if they are nested.
    (save-excursion
      (let ((bufpos t)
-          lim next-containing)
+           next-containing)
        (while (and (eq bufpos t)
                   containing-sexp)
         (when paren-state
-          (if (consp (car paren-state))
-              (setq lim (cdr (car paren-state))
-                    paren-state (cdr paren-state))
-            (setq lim (car paren-state)))
-          (when paren-state
-            (setq next-containing (car paren-state)
-                  paren-state (cdr paren-state))))
+          (setq next-containing (c-pull-open-brace paren-state)))
 
         (goto-char containing-sexp)
         (if (c-looking-at-inexpr-block next-containing next-containing)
@@ -10632,14 +10639,16 @@ comment at the start of cc-engine.el for more info."
             ;; containing sexp, so that c-looking-at-inexpr-block
             ;; doesn't check for an identifier before it.
             (setq bufpos nil)
-          (when (or (not (eq (char-after) ?{))
-                    (eq (setq bufpos (c-looking-at-or-maybe-in-bracelist
-                                      next-containing lim))
-                        t))
-            (setq containing-sexp next-containing
-                  lim nil
-                  next-containing nil))))
-       (and (consp bufpos) (car bufpos))))))
+          (if (not (eq (char-after) ?{))
+              (setq bufpos nil)
+            (when (eq (setq bufpos (c-looking-at-or-maybe-in-bracelist
+                                         next-containing next-containing))
+                      t)
+              (setq containing-sexp next-containing
+                    next-containing nil)))))
+       (and (consp bufpos)
+           (or accept-in-paren (not (eq (cdr bufpos) 'in-paren)))
+           (car bufpos))))))
 
 (defun c-looking-at-special-brace-list (&optional _lim)
   ;; If we're looking at the start of a pike-style list, i.e., `({ })',
@@ -11506,6 +11515,7 @@ comment at the start of cc-engine.el for more info."
         ;; The paren state outside `containing-sexp', or at
         ;; `indent-point' if `containing-sexp' is nil.
         (paren-state (c-parse-state))
+        (state-cache (copy-tree paren-state))
         ;; There's always at most one syntactic element which got
         ;; an anchor pos.  It's stored in syntactic-relpos.
         syntactic-relpos
@@ -11668,7 +11678,7 @@ comment at the start of cc-engine.el for more info."
               (not (c-at-vsemi-p before-ws-ip))
               (not (memq char-after-ip '(?\) ?\] ?,)))
               (or (not (eq char-before-ip ?}))
-                  (c-looking-at-inexpr-block-backward c-state-cache))
+                  (c-looking-at-inexpr-block-backward state-cache))
               (> (point)
                  (progn
                    ;; Ought to cache the result from the
@@ -11746,7 +11756,7 @@ comment at the start of cc-engine.el for more info."
        (if containing-sexp
            (progn
              (goto-char containing-sexp)
-             (setq lim (c-most-enclosing-brace c-state-cache
+             (setq lim (c-most-enclosing-brace state-cache
                                                containing-sexp))
              (c-backward-to-block-anchor lim)
              (c-add-stmt-syntax 'case-label nil t lim paren-state))
@@ -11772,7 +11782,7 @@ comment at the start of cc-engine.el for more info."
 
              (containing-sexp
               (goto-char containing-sexp)
-              (setq lim (c-most-enclosing-brace c-state-cache
+              (setq lim (c-most-enclosing-brace state-cache
                                                 containing-sexp))
               (save-excursion
                 (setq tmpsymbol
@@ -11816,7 +11826,7 @@ comment at the start of cc-engine.el for more info."
        (goto-char (cdr placeholder))
        (back-to-indentation)
        (c-add-stmt-syntax tmpsymbol nil t
-                          (c-most-enclosing-brace c-state-cache (point))
+                          (c-most-enclosing-brace state-cache (point))
                           paren-state)
        (unless (eq (point) (cdr placeholder))
          (c-add-syntax (car placeholder))))
@@ -12239,11 +12249,11 @@ comment at the start of cc-engine.el for more info."
            (and (eq (char-before) ?})
                 (save-excursion
                   (let ((start (point)))
-                    (if (and c-state-cache
-                             (consp (car c-state-cache))
-                             (eq (cdar c-state-cache) (point)))
+                    (if (and state-cache
+                             (consp (car state-cache))
+                             (eq (cdar state-cache) (point)))
                         ;; Speed up the backward search a bit.
-                        (goto-char (caar c-state-cache)))
+                        (goto-char (caar state-cache)))
                     (c-beginning-of-decl-1 containing-sexp) ; Can't use `lim' 
here.
                     (setq placeholder (point))
                     (if (= start (point))
@@ -12400,7 +12410,8 @@ comment at the start of cc-engine.el for more info."
         ((and (eq char-after-ip ?{)
               (progn
                 (setq placeholder (c-inside-bracelist-p (point)
-                                                        paren-state))
+                                                        paren-state
+                                                        nil))
                 (if placeholder
                     (setq tmpsymbol '(brace-list-open . inexpr-class))
                   (setq tmpsymbol '(block-open . inexpr-statement)
@@ -12482,7 +12493,7 @@ comment at the start of cc-engine.el for more info."
                (skip-chars-forward " \t"))
            (goto-char placeholder))
          (c-add-stmt-syntax 'arglist-cont-nonempty (list containing-sexp) t
-                            (c-most-enclosing-brace c-state-cache (point))
+                            (c-most-enclosing-brace state-cache (point))
                             paren-state))
 
         ;; CASE 7G: we are looking at just a normal arglist
@@ -12523,7 +12534,7 @@ comment at the start of cc-engine.el for more info."
                            (save-excursion
                              (goto-char containing-sexp)
                              (c-looking-at-special-brace-list)))
-                      (c-inside-bracelist-p containing-sexp paren-state))))
+                      (c-inside-bracelist-p containing-sexp paren-state t))))
        (cond
 
         ;; CASE 9A: In the middle of a special brace list opener.
@@ -12571,7 +12582,7 @@ comment at the start of cc-engine.el for more info."
                 (= (point) containing-sexp)))
          (if (eq (point) (c-point 'boi))
              (c-add-syntax 'brace-list-close (point))
-           (setq lim (c-most-enclosing-brace c-state-cache (point)))
+           (setq lim (c-most-enclosing-brace state-cache (point)))
            (c-beginning-of-statement-1 lim nil nil t)
            (c-add-stmt-syntax 'brace-list-close nil t lim paren-state)))
 
@@ -12597,7 +12608,7 @@ comment at the start of cc-engine.el for more info."
              (goto-char containing-sexp))
            (if (eq (point) (c-point 'boi))
                (c-add-syntax 'brace-list-intro (point))
-             (setq lim (c-most-enclosing-brace c-state-cache (point)))
+             (setq lim (c-most-enclosing-brace state-cache (point)))
              (c-beginning-of-statement-1 lim)
              (c-add-stmt-syntax 'brace-list-intro nil t lim paren-state)))
 
@@ -12619,7 +12630,7 @@ comment at the start of cc-engine.el for more info."
        ((and (not (memq char-before-ip '(?\; ?:)))
             (not (c-at-vsemi-p before-ws-ip))
             (or (not (eq char-before-ip ?}))
-                (c-looking-at-inexpr-block-backward c-state-cache))
+                (c-looking-at-inexpr-block-backward state-cache))
             (> (point)
                (save-excursion
                  (c-beginning-of-statement-1 containing-sexp)
@@ -12753,7 +12764,7 @@ comment at the start of cc-engine.el for more info."
              (skip-chars-forward " \t"))
          (goto-char placeholder))
        (c-add-stmt-syntax 'template-args-cont (list containing-<) t
-                          (c-most-enclosing-brace c-state-cache (point))
+                          (c-most-enclosing-brace state-cache (point))
                           paren-state))
 
        ;; CASE 17: Statement or defun catchall.
@@ -12827,7 +12838,7 @@ comment at the start of cc-engine.el for more info."
            (goto-char (cdr placeholder))
            (back-to-indentation)
            (c-add-stmt-syntax tmpsymbol nil t
-                              (c-most-enclosing-brace c-state-cache (point))
+                              (c-most-enclosing-brace state-cache (point))
                               paren-state)
            (if (/= (point) (cdr placeholder))
                (c-add-syntax (car placeholder))))