From 6800761863dd45b6055768febc6ace6a20120dc7 Mon Sep 17 00:00:00 2001
From: Ben Longbons <b.r.longbons@gmail.com>
Date: Sun, 19 Oct 2014 22:22:08 -0700
Subject: New ast module for for npc parsing

Will eventually put most/all parsers there.
---
 src/compat/result.hpp      | 78 +++++++++++++++++++++++++++++++++++++++++++++
 src/compat/result_test.cpp | 79 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 157 insertions(+)
 create mode 100644 src/compat/result.hpp
 create mode 100644 src/compat/result_test.cpp

(limited to 'src/compat')

diff --git a/src/compat/result.hpp b/src/compat/result.hpp
new file mode 100644
index 0000000..f03c026
--- /dev/null
+++ b/src/compat/result.hpp
@@ -0,0 +1,78 @@
+#pragma once
+//    result.hpp - A possibly failed return value
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU General Public License for more details.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "fwd.hpp"
+
+#include "../strings/rstring.hpp"
+
+#include "option.hpp"
+
+namespace tmwa
+{
+    namespace result
+    {
+        enum ResultMagicFlag { magic_flag };
+
+        template<class T>
+        class Result
+        {
+            Option<T> success;
+            RString failure;
+        public:
+            Result(ResultMagicFlag, T v)
+            : success(Some(std::move(v))), failure()
+            {}
+            Result(ResultMagicFlag, RString msg)
+            : success(None), failure(std::move(msg))
+            {}
+
+            bool is_ok() { return success.is_some(); }
+            bool is_err() { return !is_ok(); }
+
+            Option<T>& get_success() { return success; }
+            RString& get_failure() { return failure; }
+        };
+
+        template<class T>
+        Result<T> Ok(T v)
+        {
+            return Result<T>(magic_flag, std::move(v));
+        }
+
+        struct Err
+        {
+            RString message;
+            Err(RString m) : message(std::move(m)) {}
+
+            template<class T>
+            operator Result<T>()
+            {
+                return Result<T>(magic_flag, message);
+            }
+        };
+    } // namespace result
+    using result::Result;
+    using result::Ok;
+    using result::Err;
+
+#define TRY(r) ({ auto _res = r; TRY_UNWRAP(_res.get_success(), return ::tmwa::Err(_res.get_failure())); })
+    // TODO the existence of this as a separate macro is a bug.
+#define TRY_MOVE(r) ({ auto _res = r; TRY_UNWRAP(std::move(_res.get_success()), return ::tmwa::Err(_res.get_failure())); })
+} // namespace tmwa
diff --git a/src/compat/result_test.cpp b/src/compat/result_test.cpp
new file mode 100644
index 0000000..0fcc181
--- /dev/null
+++ b/src/compat/result_test.cpp
@@ -0,0 +1,79 @@
+#include "result.hpp"
+//    result_test.cpp - Testsuite for possibly failing return values
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU General Public License for more details.
+//
+//    You should have received a copy of the GNU General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include <gtest/gtest.h>
+
+#include "../strings/literal.hpp"
+
+//#include "../poison.hpp"
+
+
+namespace tmwa
+{
+TEST(Result, inspect)
+{
+    struct Foo
+    {
+        int val;
+
+        Foo(int v) : val(v) {}
+        Foo(Foo&&) = default;
+        Foo(const Foo&) = delete;
+        Foo& operator = (Foo&&) = default;
+        Foo& operator = (const Foo&) = delete;
+
+        bool operator == (const Foo& other) const
+        {
+            return this->val == other.val;
+        }
+    };
+
+    Result<Foo> foo = Ok(Foo(1));
+    EXPECT_TRUE(foo.is_ok());
+    EXPECT_FALSE(foo.is_err());
+    EXPECT_EQ(foo.get_success(), Some(Foo(1)));
+    EXPECT_EQ(foo.get_failure(), ""_s);
+    foo = Err("oops"_s);
+    EXPECT_FALSE(foo.is_ok());
+    EXPECT_TRUE(foo.is_err());
+    EXPECT_EQ(foo.get_success(), None<Foo>());
+    EXPECT_EQ(foo.get_failure(), "oops"_s);
+}
+
+static
+Result<int> try_you(bool b)
+{
+    return b ? Ok(0) : Err("die"_s);
+}
+
+static
+Result<int> try_me(bool b)
+{
+    return Ok(TRY(try_you(b)) + 1);
+}
+
+TEST(Result, try)
+{
+    Result<int> t = try_me(true);
+    EXPECT_EQ(t.get_success(), Some(1));
+    Result<int> f = try_me(false);
+    EXPECT_EQ(f.get_failure(), "die"_s);
+}
+} // namespace tmwa
-- 
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