Merge pull request #48 from RomanHargrave/fix-smie-hanging-indent

Fix hanging assignment indentation
Raku · Apr 12, 2021 · 3f33ca3 · 3f33ca3
2 parents 02bf289 + 73c35c0
commit 3f33ca3
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Showing 2 changed files with 75 additions and 26 deletions.
diff --git a/raku-indent.el b/raku-indent.el
@@ -11,56 +11,99 @@
 
 (defconst raku-smie-grammar
   (smie-prec2->grammar
-   (smie-precs->prec2 '((assoc ";") (assoc ",") (left ":")))))
+   (smie-precs->prec2
+    '((assoc ";") (assoc "=") (assoc ",") (left ":")))))
 
 (defcustom raku-indent-offset 4
   "Basic size of one indentation step."
   :type 'integer
   :group 'raku)
 
 (defun raku-smie--not-interpolation-p ()
-  (save-excursion
-    (forward-char -1)
-    (or (zerop (skip-chars-backward "-[:alnum:]"))
-        (not (looking-back "#{\\$" (- (point) 3))))))
+  (save-excursion                                      ;; Prepare for excursion
+    (forward-char -1)                                  ;; Retreat one char
+
+    (or
+     ;; Backtrack til we hit something that _isn't_ alnum
+     ;; If we did not backtrack, we're not in interpolation
+     (zerop (skip-chars-backward "-[:alnum:]"))
+
+     ;; If we did backtrack, see if #{\$ (EOL) occurs three
+     ;; or more characters prior to point (??????????)
+     ;; if this does NOT match, we are not in an interpolation
+     (not (looking-back "#{\\$" (- (point) 3))))))
 
 (defun raku-smie--forward-token ()
   (cond
-   ((and (eq (char-before) ?\})
-	    (raku-smie--not-interpolation-p)
-	    ;; FIXME: If the next char is not whitespace, what should we do?
-	    (or (memq (char-after) '(?\s ?\t ?\n))
-		(looking-at comment-start-skip)))
-       (if (memq (char-after) '(?\s ?\t ?\n))
-	   (forward-char 1) (forward-comment 1))
-       ";")
-   ((progn (forward-comment (point-max))
-           (looking-at "[;,:]"))
-    (forward-char 1) (match-string 0))
-   (t (smie-default-forward-token))))
+   ;; Return `;` to fudge end-of-block indentation (I think), as ; is optional after a block
+   ((and (eq (char-before) ?\})                 ;; Character immediately prior to point is `}`
+         (raku-smie--not-interpolation-p)       ;; And, not in an interpolation
+         ;; FIXME: If the next char is not whitespace, what should we do?
+         (or (memq (char-after) '(?\s ?\t ?\n)) ;; And, point is followed by \s, \t, or \n
+             (looking-at comment-start-skip)))  ;;      or point is looking-at /#+ */
+
+    (if (memq (char-after) '(?\s ?\t ?\n))      ;; If the above is true, and point is followed by /[\s\t\n]/
+        (forward-char 1) (forward-comment 1))   ;; Then, advance by one character, and one whole comment
+    ";")
+
+   ((eq (char-after) ?\=)                       ;; Spit out '=' to kick off proper indentation for hanging assignment
+    (forward-char 1)
+    "=")
+
+   ((progn (forward-comment (point-max))        ;; Read past ALL comments
+           (looking-at "[;,:]"))                ;; Are we looking at ; , or :
+
+    (forward-char 1)                            ;; If so, advance one character
+    (match-string 0))                           ;; And then return whatever looking-at found (?)
+
+   (t (smie-default-forward-token))))           ;; If none of the above matched, defer to SMIE default search
 
 (defun raku-smie--backward-token ()
   (let ((pos (point)))
-    (forward-comment (- (point)))
+    (forward-comment (- (point)))               ;; Retreate past ALL comments up to point
     (cond
      ;; FIXME: If the next char is not whitespace, what should we do?
-     ((and (eq (char-before) ?\}) (raku-smie--not-interpolation-p)
-           (> pos (point))) ";")
-     ((memq (char-before) '(?\; ?\, ?\:))
-      (forward-char -1) (string (char-after)))
-     (t (smie-default-backward-token)))))
+     ;; Cond #1 - Same end-of-block hack, I think
+     ((and (eq (char-before) ?\})               ;; Point is preceded immediately by `}`
+           (raku-smie--not-interpolation-p)     ;; And, not in an interpolation
+           (> pos (point)))                     ;; And, point has moved backward
+
+      ";")                                      ;; If so, yield ';'
+
+     ((eq (char-before) ?\=)
+      (forward-char -1)
+      "=")
+
+     ;; Cond #2 - Get whatever precedes [,:;]
+     ((memq (char-before) '(?\; ?\, ?\:))       ;; Point is preceded immediately by `;`, `,`, or `:`
+      (forward-char -1)                         ;; Retreat one char
+      (string (char-after)))                    ;; Return char after point (the char we just retreated past)
+
+     (t (smie-default-backward-token)))))       ;; If none of the above matched, defer to SMIE default search
 
 (defun raku-smie-rules (kind token)
   (pcase (cons kind token)
+    ;; Basic indent offset
     (`(:elem . basic) raku-indent-offset)
+
+    ;; Indent offset for function args
     (`(:elem . arg) 0)
+
     (`(:list-intro . ,(or `";" `"")) t) ;"" stands for BOB (bug#15467).
+
+    ;; Make sure that hanging assignment gets indented
+    (`(:before . "=")
+     (if (smie-rule-hanging-p)
+         (smie-rule-parent raku-indent-offset)))
+
     (`(:before . "{")
-     (when (smie-rule-hanging-p)
-       (smie-backward-sexp ";")
+     (when (smie-rule-hanging-p) ; is `{` the last thing on this line?
+       (smie-backward-sexp ";")  ; y tho
        (smie-indent-virtual)))
+
     (`(:before . ,(or "{" "("))
-     (if (smie-rule-hanging-p) (smie-rule-parent 0)))))
+     (if (smie-rule-hanging-p)
+         (smie-rule-parent 0)))))
 
 (provide 'raku-indent)
 

diff --git a/test/test-smie.p6 b/test/test-smie.p6
@@ -5,3 +5,9 @@ qq:to/HERE/;
     by emacs. (Except maybe to have left overhanging lines
     adjusted.)
     HERE
+
+my %var =
+   A => 1,
+   :b<2>,
+   :3c,
+   D => 4;