more improvements to repl

repl.py

@@ -1,26 +1,40 @@
-import wasp.parser as parser
+import wasp
+import wasp.parser
+import readline
+
+readline.parse_and_bind("tab: complete")
 
 
 class Reader(object):
-    def __init__(self):
-        pass
+    def __init__(self, prompt, banner=None):
+        self.prompt = prompt
+        self.banner = banner
 
     def __iter__(self):
+        if self.banner:
+            print self.banner
         return self
 
-    def __next__(self):
-        return self.next()
-
     def next(self):
         try:
-            return raw_input(">> ")
+            return raw_input(self.prompt)
+        except KeyboardInterrupt:
+            return None
         except EOFError:
             raise StopIteration()
 
 
 if __name__ == "__main__":
-    for line in Reader():
-        ptree = parser.parse(line)
+    for line in Reader(">> ", banner="WASP %s" % wasp.VERSION):
+        if line == "" or line is None:
+            continue
+
+        try:
+            ptree = wasp.parser.parse(line)
+        except ValueError, e:
+            print e.message
+            continue
+
         print " ^ %s" % ptree
         ast = ptree.ast()
         print " ‡ %r" % ast

wasp/__init__.py

@@ -0,0 +1 @@
+VERSION = '0.0.1'