Added js-expander.el

diff --git a/extras/js-expander.el b/extras/js-expander.el
new file mode 100644 (file)
index 0000000..63e928a
--- /dev/null
+++ b/extras/js-expander.el
@@ -0,0 +1,47 @@
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;;; What this code does: put your cursor at a ParenScript expression
+;;;; in a ParenScript file and type 'C-c j' to bring up a buffer with
+;;;; the resulting Javascript code. This feature depends on Slime (and
+;;;; your ParenScript buffer being in slime-mode; it doesn't work in
+;;;; slime-repl-mode, which is intentional). It is inspired (and works
+;;;; like) the Slime 'C-c M-m' macroexpansion feature.
+
+;;;; Copyright 2007, Vladimir Sedach. See the COPYING file in the
+;;;; above directory for licensing information.
+
+;;; The code below is a generic facility for adding "macroexpand-like" buffer expansion to Slime
+(defun slime-eval-custom-expand (expander exp-str package buffer-name buffer-mode printer)
+  (lexical-let ((package package)
+                (buffer-name buffer-name)
+                (buffer-mode buffer-mode)
+                (printer printer))
+    (slime-eval-async
+     (list 'swank:eval-and-grab-output (format "(%s %s)" expander exp-str))
+     (lambda (expansion)
+       (with-current-buffer (slime-get-temp-buffer-create buffer-name :mode buffer-mode :reusep t)
+         (setq slime-buffer-connection (slime-connection))
+         (setq slime-buffer-package package)
+         (setq buffer-read-only nil)
+         (erase-buffer)
+         (insert (funcall printer (second expansion)))
+         (setq buffer-read-only t)
+         (font-lock-fontify-buffer)))
+     package)))
+
+(defun* slime-add-custom-expander (key expander buffer-name &optional (buffer-mode 'slime-mode) (printer #'identity))
+  (slime-define-key key (lexical-let ((expander expander)
+                                      (buffer-name buffer-name)
+                                      (buffer-mode buffer-mode)
+                                      (printer printer))
+                          (lambda (&rest _)
+                            (interactive "P")
+                            (slime-eval-custom-expand expander
+                                                      (first (slime-sexp-at-point-for-macroexpansion))
+                                                      (slime-current-package)
+                                                      buffer-name
+                                                      buffer-mode
+                                                      printer)))
+                    :prefixed t :inferior t))
+
+;;; This actually defines the expander. If the code above belongs in slime.el, the code below would go into .emacs
+(slime-add-custom-expander "j" 'js:js "*ParenScript generated Javascript*" 'c-mode #'read)