Got indentation mostly working. Needs cleanup.

krl-mode.el

@@ -9,29 +9,69 @@
 (add-to-list 'auto-mode-alist '("\\.dat\\'" . krl-mode))
 (add-to-list 'auto-mode-alist '("\\.sub\\'" . krl-mode))
 
-(defconst krl-keywords
+(defun rstrip (str)
+  "Strip tailing whitespace from STR."
+  (replace-regexp-in-string (rx (* (any " \t\n")) eos) "" str))
+
+;; Blocks allowed only at top level.
+;; TODO: These should be regexes as well. (If trailing ws should be allowed...)
+(defconst krl-keywords-toplevel-block-pairs
+  '(
+    ("DEF " "END\n")
+    ("DEFFCT " "ENDFCT\n")
+    ))
+
+(defun regexp-opt-allow-ind (str-list &optional prefix)
+  "Optimize regex for a list of strings, allowing for leading whitespace."
+  (concat "^ *" prefix (regexp-opt str-list t)))
+
+(defun list-nth (i pair-list)
+  (mapcar (lambda (x) (nth i x)) pair-list))
+
+(defconst krl-indent-regex-toplevel-block-open
+  (regexp-opt-allow-ind (list-nth 0 krl-keywords-toplevel-block-pairs) "\\(GLOBAL +\\)?"))
+(defconst krl-indent-regex-toplevel-block-close
+  (regexp-opt-allow-ind (list-nth 1 krl-keywords-toplevel-block-pairs)))
+
+;; Blocks not allowed at top level. Arb. nestable.
+;; The whitespace indicates expected
+(defconst krl-keywords-nested-block-pairs
+  '(
+    ;; Loops
+    ("FOR " "ENDFOR\n")
+    ("WHILE " "ENDWHILE\n")
+    ("REPEAT\n" "UNTIL ")
+    ("LOOP\n" "ENDLOOP\n")
+    ;; Branches
+    ("IF " "ENDIF\n")
+    ("SWITCH " "ENDSWITCH\n")
+    ("SPLINE" "ENDSPLINE\n")
+    ))
+
+(defconst krl-keywords-nested-block-middle
+  '(
+    ("IF " "ENDIF\n" "ELSE\n")
+    ("SWITCH " "ENDSWITCH\n" "CASE ")
+    ))
+
+(defconst krl-indent-regex-nested-block-middle
+  (regexp-opt-allow-ind (list-nth 2 krl-keywords-nested-block-middle)))
+
+(defconst krl-indent-regex-nested-block-open
+  (regexp-opt-allow-ind (append (list-nth 0 krl-keywords-nested-block-pairs))))
+
+(defconst krl-indent-regex-nested-block-close
+  (regexp-opt-allow-ind (list-nth 1 krl-keywords-nested-block-pairs)))
+
+;; See SI p360.
+(defconst krl-keywords-misc
   '(
-    "DEF"
-    "END"
     "DEFDAT"
     "ENDDAT"
-    "DEFFCT"
-    "ENDFCT"
     "DECL"
-    "RETURN"
+    "GLOBAL"
-    "FOR"
+    "PUBLIC"
-    "TO"
-    "ENDFOR"
-    "WHILE"
-    "ENDWHILE"
-    "IF"
     "THEN"
-    "ELSE"
-    "ENDIF"
-    "SWITCH"
-    "CASE"
-    "ENDSWITCH"
-    "LOOP"
     "ENUM"
     "NOT"
     "AND"
@@ -44,15 +84,28 @@
     "INTERRUPT"
     "WHEN"
     "DO"
-                                        ; TODO: Add more stuff.
+    "STEP"
+    "WHEN"
     ))
 
+(defconst krl-keywords
+  (append
+  (mapcar (lambda (x) (rstrip (nth 0 x))) krl-keywords-toplevel-block-pairs)
+  (mapcar (lambda (x) (rstrip (nth 1 x))) krl-keywords-toplevel-block-pairs)
+  (mapcar (lambda (x) (rstrip (nth 0 x))) krl-keywords-nested-block-pairs)
+  (mapcar (lambda (x) (rstrip (nth 1 x))) krl-keywords-nested-block-pairs)
+  (mapcar (lambda (x) (rstrip (nth 2 x))) krl-keywords-nested-block-middle)
+  krl-keywords-misc
+   ))
+
 (defconst krl-warning-keywords
   '(
     "HALT"
     "BRAKE"
     "EXIT"
     "WAIT"
+    "TRIGGER"
+    "!"                                 ; Placeholder for positions.
     ))
 
 (defconst krl-types
@@ -72,8 +125,10 @@
     "FALSE"
     "$NULLFRAME"
     "$ROBROOT"
+    "XHOME"
     ))
 
+;; TODO: Kinda flexible about what we consider builtins...
 (defconst krl-builtins
   '(
                                         ; Motion
@@ -82,6 +137,10 @@
     "PTP_REL"
     "LIN"
     "CIRC"
+    "SPL"
+    "SPTP"
+    "SLIN"
+    "SCIRC"
                                         ; Num functions
     "ABS"
     "SQRT"
@@ -126,6 +185,130 @@
     st)
   "Syntax table for krl-mode")
 
+;; Get the string pair for the block we are currently on the end of.
+(defun krl-get-pair ()
+  (let ((pairs (copy-sequence krl-keywords-nested-block-pairs)) (pair nil))
+      (while (and (not pair) pairs)
+        (when (looking-at (concat "^ *" (nth 1 (car pairs))))
+          (setq pair (car pairs)))
+        (setq pairs (cdr pairs)))
+      ;; FIXME: Hack for broken ELSE, CASE.
+      (when (not pair)
+        (let ((triples (copy-sequence krl-keywords-nested-block-middle)))
+          (while (and (not pair) triples)
+            (when (looking-at (concat "^ *" (nth 2 (car triples))))
+              (setq pair (car triples)))
+            (setq triples (cdr triples))
+          )))
+      pair))
+
+(defun krl-indent-of-matching ()
+  (save-excursion
+    (let ((balance 1) (pair (krl-get-pair)))
+      ;(message (nth 0 pair))
+      (while (and (/= balance 0) (not (bobp)))
+        (progn
+          (forward-line -1)
+          (if (looking-at (concat "^ *" (nth 0 pair)))
+              (setq balance (1- balance)))
+          (if (looking-at (concat "^ *" (nth 1 pair)))
+              (setq balance (1+ balance)))
+          ))
+      (current-indentation)
+      )))
+
+(defun krl-indent-of-block-opener ()
+  (save-excursion
+    (let (done)
+      (while (and (not done) (not (bobp)))
+        (forward-line -1)
+        (when (looking-at krl-indent-regex-nested-block-open)
+          (setq done t))
+        (when (looking-at krl-indent-regex-toplevel-block-open)
+          (setq done t))
+        )
+      (current-indentation)
+      )))
+
+(defun krl-indent-of-block-end ()
+  (save-excursion
+    (let (done)
+      (while (and (not done) (not (bobp)))
+        (forward-line -1)
+        (when (looking-at " *END.*")
+          (setq done t))
+        )
+      (current-indentation)
+      )))
+
+(defun krl-find-hinted-indent ()
+  (save-excursion
+    (let ((ind))
+      (while (and (not ind) (not (bobp)))
+        (forward-line -1)
+        (cond
+         ((looking-at krl-indent-regex-toplevel-block-close)
+          ;(message "found tlb close")
+          (setq ind 0))
+         ((looking-at krl-indent-regex-toplevel-block-open)
+          ;(message "found tlb open")
+          (setq ind (+ 2 (current-indentation))))
+         ((looking-at krl-indent-regex-nested-block-close)
+          ;(message "found nb close")
+          (setq ind (current-indentation)))
+         ((looking-at krl-indent-regex-nested-block-open)
+          ;(message "found nb open")
+          (setq ind (+ 2 (current-indentation))))
+         (t
+          ;(message "found other")
+          )
+         ))
+      ind)))
+
+(defun krl-indent-line ()
+  "Indent current line as KRL."
+  (interactive)
+  (save-excursion
+    (progn
+      (beginning-of-line)
+      (if (bobp)
+          (indent-line-to 0)
+        (let (indent-curr)
+          (progn
+            (cond ((looking-at krl-indent-regex-toplevel-block-open)
+                   (progn
+                     ;(message "toplevel open")
+                     (indent-line-to 0)))
+                  ((looking-at krl-indent-regex-toplevel-block-close)
+                   (progn
+                     ;(message "toplevel close")
+                     (indent-line-to 0)))
+                  ((looking-at "^ *&")
+                   (progn
+                     ;(message "&")
+                     ;; HMI editor crud.
+                     (indent-line-to 0)))
+                  ((looking-at krl-indent-regex-nested-block-close)
+                   (progn
+                     ;(message "nested close")
+                     (indent-line-to (krl-indent-of-matching))))
+                  ((looking-at krl-indent-regex-nested-block-middle)
+                   (progn
+                     ;(message "annoying stuff")
+                     ;; (indent-line-to (krl-indent-of-block-opener))))
+                     (indent-line-to (krl-indent-of-matching))))
+                  (t
+                   (progn
+                     ;(message "other")
+                     ;; ;(message krl-indent-regex-toplevel-block-open)
+                     ;; (indent-line-to (krl-find-hinted-indent))))
+                     (let ((hinted-indent (krl-find-hinted-indent)))
+                       (when (not hinted-indent)
+                         (setq hinted-indent 0))
+                       (indent-line-to hinted-indent))))
+            )))))))
+
+
 (defun krl-mode ()
   "Major mode for editing KRL files"
   (interactive)
@@ -133,6 +316,7 @@
   (set-syntax-table krl-mode-syntax-table)
   (use-local-map krl-mode-map)
   (set (make-local-variable 'font-lock-defaults) '(krl-font-lock-keywords))
+  (set (make-local-variable 'indent-line-function) 'krl-indent-line)
   (setq major-mode 'krl-mode)
   (setq mode-name "KRL")
   (run-hooks 'krl-mode-hook))