Cut folly/futures/exercises/

Summary: [Folly] Cut `folly/futures/exercises/`, which was never finished.

Reviewed By: fugalh

Differential Revision: D18149557

fbshipit-source-id: ec5654c2d37996c42a3673523422bafe2a64c89e

folly/futures/exercises/01-Values.cpp

-/*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * 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.
- */
-
-#include <folly/futures/Future.h>
-
-#include <folly/futures/exercises/Koan.h>
-
-using folly::Future;
-using folly::makeFuture;
-
-#if 0 // compilation cursor
-
-TEST(Values, canonicalForm) {
-  // The canonical way to make a Future from an immediate value is with the
-  // Future constructor.
-  Future<int> answer(__);
-  EXPECT_EQ(42, answer.get());
-}
-
-TEST(Values, typeDeduction) {
-  // If you use makeFuture, the compiler will deduce the type.
-  auto answer = makeFuture(__);
-  EXPECT_EQ(42, answer.get());
-}
-
-TEST(Values, exceptionNeedsType) {
-  // To create a Future holding an exception, you must
-  // use makeFuture with the type
-  std::runtime_error err("Don't Panic");
-  auto question = __(err);
-  // not
-  //auto question = makeFuture(err);
-  EXPECT_THROW(question.get(), std::runtime_error);
-}
-
-TEST(Values, typeConversion) {
-  // Sometimes it's cleaner to give the type and let the compiler do implicit
-  // type conversion
-  __ answer(42);
-  // not
-  //auto answer = makeFuture((double)42);
-  EXPECT_EQ(__, answer.get());
-}
-
-using folly::Try;
-
-TEST(Values, tryInside) {
-  // Futures hold either a Value or Exception. This is accomplished under the
-  // covers with Try
-  Try<int> t = makeFuture(42).__();
-  EXPECT_TRUE(t.hasValue());
-  EXPECT_EQ(42, t.value());
-
-  t = Future<int>(std::runtime_error("Don't Panic")).__();
-  EXPECT_TRUE(t.hasException());
-  EXPECT_THROW(t.value(), std::runtime_error);
-}
-
-#endif

folly/futures/exercises/Koan.h

-/*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * 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.
- */
-
-#pragma once
-
-#include <gflags/gflags.h>
-#include <gtest/gtest.h>
-
-#include <folly/Portability.h>

folly/futures/exercises/README.md

-Working through [Programming Koans][1] can be a fun, lightweight, and fast way to
-learn a new language or pattern with small, focused exercises. Therefore, we
-present Koans for Futures.  Perhaps you will call them "Koans to Be".
-
-Edit the topical files one at a time, moving the "compilation cursor" down one
-exercise at a time, and getting them to pass by filling in the blanks.
-
-[1] http://www.lauradhamilton.com/learn-a-new-programming-language-today-with-koans
-[2] http://catb.org/esr/writings/unix-koans/ten-thousand.html

folly/futures/exercises/main.cpp

-/*
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * 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.
- */
-
-#include <folly/futures/exercises/Koan.h>
-
-int main(int argc, char** argv) {
-  ::testing::InitGoogleTest(&argc, argv);
-  ::gflags::ParseCommandLineFlags(&argc, &argv, true);
-  return RUN_ALL_TESTS();
-}