1 files changed, 38 insertions, 4 deletions
diff --git a/src/parse.lisp b/src/parse.lisp
index 8bd8c50..3052583 100644
--- a/src/parse.lisp
+++ b/src/parse.lisp
@@ -1,9 +1,20 @@
-(in-package #:parse)
+helper(in-package #:parse)
+
+(define-condition parser-error (error)
+  ((message :initarg :message
+            :initform nil
+            :reader message))
+  (:report (lambda (condition stream)
+             (format stream "~A" (message condition))))
+  (:documentation "Dedicated error for an invalid parse."))
 
 (defun tokens->ast (program)
-  (let ((program (remove nil (mapcar #'extract-label program))))
-    ;; TODO
-    program))
+  "Given PROGRAM, which is a list of lists of symbols,
+filters out the labels and parses."
+  ;; TODO add directives
+  (let ((program (remove nil (mapcar #'extract-label program)))
+        (i 0))
+    (mapcar (lambda (l) (extract-instruction l i)) program)))
 
 (let ((i 0))
   (defun extract-label (line)
@@ -19,3 +30,26 @@ processing."
              (satisfies (lambda (x) (equal x 'lex::colon))))
        (progn (push (cons (read-from-string id) i) util:label-loc) nil))
       (_ (progn (incf i) line)))))
+
+(defun extract-instruction (line i)
+  "Given instruction LINE, determines the expected type format and passes
+LINE and the index I to the the respective function."
+  ;; TODO add pseudo-ops (i.e., nop, mov, ...)
+  (let* ((type-map '((r-type . extract-r-type)
+                     (i-type . extract-i-type)
+                     (j-type . extract-j-type)))
+         (keyword (car line))
+         (type-fn (cdr (assoc keyword type-map))))
+    (if type-fn
+        (funcall type-fn line i)
+        (error 'parser-error
+               (format nil "PARSE failed--~a is not a known keyword.~%" (keyword))))))
+
+(defun extract-r-type (line i)
+  'r)
+
+(defun extract-i-type (line i)
+  'i)
+
+(defun extract-j-type (line i)
+  'j)