[WIP] Added lambda list keyword parsing step

This allows us to translate lisp argument lists to Python ones.

(defun foo (x y &rest z &optional {foo 3} &aux kwargs))

translates roughly to:

def foo(x, y, *z, foo=3, **kwargs):
  pass

hy/compiler.py

@@ -22,6 +22,7 @@ from hy.errors import HyError
 
 from hy.models.expression import HyExpression
 from hy.models.integer import HyInteger
+from hy.models.lambdalist import HyLambdaListKeyword
 from hy.models.string import HyString
 from hy.models.symbol import HySymbol
 from hy.models.list import HyList
@@ -80,6 +81,10 @@ class HyASTCompiler(object):
         ret.reverse()
         return ret
 
+    def _parse_lambda_list(self, exprs):
+        """ Return args, keywords, starargs, kwargs from exprs."""
+        return [self.compile(expr) for expr in exprs], [], None, None
+
     @builds(list)
     def compile_raw_list(self, entries):
         return [self.compile(x) for x in entries]
@@ -481,11 +486,13 @@ class HyASTCompiler(object):
             if expression[0].startswith("."):
                 return self.compile_dotted_expression(expression)
 
+        args, keywords, starargs, kwargs = self._parse_lambda_list(expression[1:])
+
         return ast.Call(func=self.compile(fn),
-                        args=[self.compile(x) for x in expression[1:]],
+                        args=args,
-                        keywords=[],
+                        keywords=keywords,
-                        starargs=None,
+                        starargs=starargs,
-                        kwargs=None,
+                        kwargs=kwargs,
                         lineno=expression.start_line,
                         col_offset=expression.start_column)
 

tests/compilers/test_ast.py

@@ -101,3 +101,8 @@ def test_ast_tuple():
     """ Ensure tuples work. """
     code = hy_compile(tokenize("(, 1 2 3)")).body[0].value
     assert type(code) == ast.Tuple
+
+
+def test_lambda_list_keywords_rest():
+    code = hy_compile(tokenize("(defun foo (x &rest xs))"))
+    assert False == True