Add support for 'functools.partial' like functionality. (#34)

* Add support for 'functools.partial' like functionality.

https://docs.python.org/3/library/functools.html#functools.partial

2 files changed, 88 insertions, 0 deletions

diff --git a/tests/BUILD b/tests/BUILD
index 9df7585..5dd8a68 100644
--- a/tests/BUILD
+++ b/tests/BUILD
@@ -1,5 +1,6 @@
 load(":collections_tests.bzl", "collections_test_suite")
 load(":dicts_tests.bzl", "dicts_test_suite")
+load(":partial_tests.bzl", "partial_test_suite")
 load(":paths_tests.bzl", "paths_test_suite")
 load(":selects_tests.bzl", "selects_test_suite")
 load(":sets_tests.bzl", "sets_test_suite")
@@ -13,6 +14,8 @@ collections_test_suite()
 
 dicts_test_suite()
 
+partial_test_suite()
+
 paths_test_suite()
 
 selects_test_suite()
diff --git a/tests/partial_tests.bzl b/tests/partial_tests.bzl
new file mode 100644
index 0000000..6e4768b
--- /dev/null
+++ b/tests/partial_tests.bzl
@@ -0,0 +1,85 @@
+# Copyright 2018 The Bazel Authors. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Unit tests for partial.bzl."""
+
+load("//:lib.bzl", "partial", "asserts", "unittest")
+
+
+def _make_noargs_nokwargs():
+  """Test utility for no args no kwargs case"""
+  return 1
+
+def _make_args_nokwargs(arg1, arg2, arg3):
+  """Test utility for args no kwargs case"""
+  return arg1 + arg2 + arg3
+
+def _make_args_kwargs(arg1, arg2, arg3, **kwargs):
+  """Test utility for args and kwargs case"""
+  return arg1 + arg2 + arg3 + kwargs["x"] + kwargs["y"]
+
+def _call_noargs_nokwargs(call_arg1):
+  """Test utility no args no kwargs case where values passed from call site"""
+  return call_arg1;
+
+def _call_args_nokwargs(func_arg1, call_arg1):
+  """Test utility for args no kwargs case where values passed from call site"""
+  return func_arg1 + call_arg1;
+
+def _call_args_kwargs(func_arg1, call_arg1, func_mult, call_mult):
+  """Test utility for args and kwargs case where values passed from call site"""
+  return (func_arg1 + call_arg1) * func_mult * call_mult;
+
+def _make_call_test(ctx):
+  """Unit tests for partial.make and partial.call."""
+  env = unittest.begin(ctx)
+
+  # Test cases where there are no args (or kwargs) at the make site, only
+  # at the call site.
+  foo = partial.make(_make_noargs_nokwargs)
+  asserts.equals(env, 1, partial.call(foo))
+
+  foo = partial.make(_make_args_nokwargs)
+  asserts.equals(env, 6, partial.call(foo, 1, 2, 3))
+
+  foo = partial.make(_make_args_kwargs)
+  asserts.equals(env, 15, partial.call(foo, 1, 2, 3, x=4, y=5))
+
+  # Test cases where there are args (and/or kwargs) at the make site and the
+  # call site.
+  foo = partial.make(_call_noargs_nokwargs, 100)
+  asserts.equals(env, 100, partial.call(foo))
+
+  foo = partial.make(_call_args_nokwargs, 100)
+  asserts.equals(env, 112, partial.call(foo, 12))
+
+  foo = partial.make(_call_args_kwargs, 100, func_mult=10)
+  asserts.equals(env, 2240, partial.call(foo, 12, call_mult=2))
+
+  # Test case where there are args and kwargs ath the make site, and the call
+  # site overrides some make site args.
+  foo = partial.make(_call_args_kwargs, 100, func_mult=10)
+  asserts.equals(env, 1120, partial.call(foo, 12, func_mult=5, call_mult=2))
+
+  unittest.end(env)
+
+make_call_test = unittest.make(_make_call_test)
+
+
+def partial_test_suite():
+  """Creates the test targets and test suite for partial.bzl tests."""
+  unittest.suite(
+      "partial_tests",
+      make_call_test,
+  )