Store ASM-FUNCTIONs in a hash table keyed on name

TODO: Populate the table based on the asm source code declaration
comments and signal an error when a named function is missing.

wip-duuqnd/user-side-compiler/asm-function.lisp

@@ -1,10 +1,14 @@
 (in-package #:user-side-compiler)
 
-;;; STUB, TODO
+(defvar *asm-functions* (make-hash-table :test #'equalp))
 
 (defclass asm-function ()
   ((%name :accessor name :initarg :name)))
 
 (define-transformation (token (token-name asm-function))
-  ;; TODO: Choose from a list, don't just create like this
-  (make-instance 'asm-function :name (name token)))
+  (multiple-value-bind (asm-function existsp)
+      (gethash (name token) *asm-functions*)
+    (if existsp
+        asm-function
+        (setf (gethash (name token) *asm-functions*)
+              (make-instance 'asm-function :name (name token))))))