Implemented interpreter, almost fully documented

improved/interpreter.py

@@ -1,2 +1,27 @@
-def callIMP(chars):
+"""The interpreter"""
+from .parser import parse
+from .tokenize import tokenize
+
+class ParseError(Exception):
     pass
+
+def callIMP(chars):
+    """
+        The entry point for everyone who wants to call
+        IMP from within Python. The function either
+        returns the value or None, if the call did not
+        succeed.
+
+        chars -- the string to evaluate
+
+        returns -- the IMP environment | None
+    """
+    if not chars: return None
+    tokens = tokenize(chars)
+    if not tokens: raise ParseError("tokens could not be generated")
+    parsed = parse(tokens)
+    if not parsed or not parsed.value: raise ParseError("tokens could not be parsed")
+    ast = parsed.value
+    env = {}
+    ast.eval(env)
+    return env