Merge pull request #1013 from timmartin/bug1010

In python 3.3+, generator functions always return a value
This commit is contained in:
Paul‮etnomailgaT‭ 2016-01-03 12:37:35 -05:00
commit 14c412c286
2 changed files with 40 additions and 1 deletions

View File

@ -2309,7 +2309,10 @@ class HyASTCompiler(object):
return ret
if body.expr:
if body.contains_yield:
if body.contains_yield and not PY33:
# Prior to PEP 380 (introduced in Python 3.3)
# generators may not have a value in a return
# statement.
body += body.expr_as_stmt()
else:
body += ast.Return(value=body.expr,

View File

@ -26,6 +26,8 @@ from hy import compiler
from hy.models.expression import HyExpression
from hy.models.list import HyList
from hy.models.symbol import HySymbol
from hy.models.integer import HyInteger
from hy._compat import PY33
if sys.version_info[0] <= 2 and sys.version_info[1] <= 6:
import unittest2 as unittest
@ -98,3 +100,37 @@ class HyASTCompilerTest(unittest.TestCase):
expr = ret.expr
self.assertIsInstance(expr, ast.Name)
self.assertEqual(expr.id, "c")
def test_compiler_yield_return(self):
"""
Check that the compiler correctly generates return statements for
a generator function. In Python versions prior to 3.3, the return
statement in a generator can't take a value, so the final expression
should not generate a return statement. From 3.3 onwards a return
value should be generated.
"""
ret = self.c.compile_function_def(
self._make_expression(HySymbol("fn"),
HyList(),
HyExpression([HySymbol("yield"),
HyInteger(2)]),
HyExpression([HySymbol("+"),
HyInteger(1),
HyInteger(1)])))
self.assertEqual(len(ret.stmts), 1)
stmt = ret.stmts[0]
self.assertIsInstance(stmt, ast.FunctionDef)
body = stmt.body
self.assertEquals(len(body), 2)
self.assertIsInstance(body[0], ast.Expr)
self.assertIsInstance(body[0].value, ast.Yield)
if PY33:
# From 3.3+, the final statement becomes a return value
self.assertIsInstance(body[1], ast.Return)
self.assertIsInstance(body[1].value, ast.BinOp)
else:
# In earlier versions, the expression is not returned
self.assertIsInstance(body[1], ast.Expr)
self.assertIsInstance(body[1].value, ast.BinOp)