Eldoc and start of keywords for gff section.

diff --git a/pico8.el b/pico8.el
index 0bb0d19ef63651a2e7f9ccf17b56e14ad3cc8d15..7600345ef7d7e4d440def660b68c96d4904dc336 100644 (file)
--- a/pico8.el
+++ b/pico8.el
@@ -25,6 +25,7 @@
 (require 'lua-mode)
 (require 'thingatpt)
 (require 'dash)
+(require 'calc-bin)
 
 
 (defgroup pico8 nil
@@ -256,15 +257,40 @@ Make sure it is installed, and present in ‘pico8-executable-paths’")))
           (col (current-column)))
       (+ (* 128 row) (/ col 2)))))
 
+(defun pico8-gff-eldoc ()
+  "Show information about the flag under the point."
+  (save-excursion
+    (when (cl-oddp (current-column))
+      (backward-char))
+    (when (looking-at "..")
+      (let* ((hex (substring-no-properties (match-string 0)))
+             (int (string-to-number hex 16)))
+        (format "%08d  %3d  %02x"
+                (let ((calc-number-radix 2))
+                  (string-to-number (math-format-radix int)))
+                int int)))))
+
+(defconst pico8-gff-font-lock-keywords
+  '(("..\n?" 0
+     (prog1 nil
+       ;; TODO: Lots of work to do here…
+       (let ((pdl (or (car (overlays-at (match-beginning 0)))
+                      (make-overlay (match-beginning 0) (match-end 0)))))
+         (overlay-put pdl 'after-string " "))))))
+
+
 (define-derived-mode pico8-gff-mode pico8-data-mode
   '(:eval (format "Flag[%d]" (pico8-gff-lighter)))
-  "Major mode for editing flags in PICO-8 cartridges.")
+  "Major mode for editing flags in PICO-8 cartridges."
+  (font-lock-add-keywords nil pico8-gff-font-lock-keywords)
+  (setq-local eldoc-documentation-function #'pico8-gff-eldoc))
 
 (defun pico8-gff-offset-of-flag (flag)
   "Calculate the offset of of flag number FLAG."
   (unless (<= 0 flag 255)
     (error "Valid flag numbers are 0 to 255, inclusive"))
   (+ (* 2 flag) (if (> flag 128) 1 0)))
+
 \f
 (defface pico8-pixel
   '((t (:inherit pico8-data :height 100)))