Switch MATCH to separate begin/end macros

The for loop trick turned out to be very prone to infinite loops
at runtime. It's better to force compiler errors even if it's ugly.

4 files changed, 60 insertions, 95 deletions

diff --git a/src/compat/attr.hpp b/src/compat/attr.hpp
index 9ddf654..5ebef6d 100644
--- a/src/compat/attr.hpp
+++ b/src/compat/attr.hpp
@@ -30,28 +30,4 @@ namespace tmwa
 #endif
 
 #define JOIN(a, b) a##b
-
-//  first loop:
-//      declare flag 'guard' (initially true)
-//      declare flag 'broken' (initially false)
-//      condition is 'guard' must be true, which is the case only for the first iteration
-//      post checks 'broken' and if set, break the loop
-//  second loop:
-//      declare public 'var' variable
-//      condition is that 'guard' must be true
-//      post sets 'guard' to false to make this loop run only once
-//  third loop:
-//      enable broken flag; it will remain set if 'break' is in the loop
-//      condition is that 'broken' must be true
-//      post sets 'broken' to false, which then fails the condition
-//      if user has a 'break' inside, then 'broken' will be true
-//      in either case, go back to the second loop's post
-#define WITH_VAR_INLOOP(ty, var, expr)                                                                                          \
-    for (bool JOIN(var, _guard) = true, JOIN(var, _broken) = false; JOIN(var, _guard); ({if (JOIN(var, _broken)) { break; } })) \
-        for (ty var = expr; JOIN(var, _guard); JOIN(var, _guard) = false)                                                       \
-            for (JOIN(var, _broken) = true; JOIN(var, _broken); JOIN(var, _broken) = false)
-#define WITH_VAR_NOLOOP(ty, var, expr)                                                                                          \
-    for (bool JOIN(var, _guard) = true, JOIN(var, _broken) = false; JOIN(var, _guard); ({if (JOIN(var, _broken)) {abort();} })) \
-        for (ty var = expr; JOIN(var, _guard); JOIN(var, _guard) = false)                                                       \
-            for (JOIN(var, _broken) = true; JOIN(var, _broken); JOIN(var, _broken) = false)
 } // namespace tmwa
diff --git a/src/compat/attr_test.cpp b/src/compat/attr_test.cpp
deleted file mode 100644
index eb9042d..0000000
--- a/src/compat/attr_test.cpp
+++ /dev/null
@@ -1,50 +0,0 @@
-#include "attr.hpp"
-//    attr_test.cpp - Tests for attributes
-//
-//    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 "../poison.hpp"
-
-
-namespace tmwa
-{
-TEST(attr, withvar)
-{
-    int x = 41;
-    for (int i = 0; i < 2; ++i)
-    {
-        WITH_VAR_NOLOOP(auto, y, x + 1)
-        {
-            x = y;
-        }
-    }
-    EXPECT_EQ(x, 43);
-    for (int i = 0; i < 2; ++i)
-    {
-        if (i == 1)
-            WITH_VAR_INLOOP(auto, y, i)
-            {
-                x = y;
-                break;
-            }
-    }
-    EXPECT_EQ(x, 1);
-}
-} // namespace tmwa
diff --git a/src/compat/option.hpp b/src/compat/option.hpp
index 7beef6f..b6e7655 100644
--- a/src/compat/option.hpp
+++ b/src/compat/option.hpp
@@ -24,8 +24,6 @@
 
 #include <utility>
 
-#include "attr.hpp"
-
 
 namespace tmwa
 {
@@ -423,13 +421,46 @@ namespace option
         if (o.maybe_ref.is_none()) falsy;                       \
         tmwa::option::option_unwrap(std::move(o));              \
     }).maybe_ref_fun()
-// immediately preceded by 'if'; not double-eval-safe
-#define OPTION_IS_SOME_INLOOP(var, expr)    \
-    ((expr).is_some())                      \
-    WITH_VAR_INLOOP(auto&, var, *(expr).ptr_or(nullptr))
-#define OPTION_IS_SOME_NOLOOP(var, expr)    \
-    ((expr).is_some())                      \
-    WITH_VAR_NOLOOP(auto&, var, *(expr).ptr_or(nullptr))
+
+#define OMATCH_BEGIN(expr)              \
+    {                                   \
+        auto&& _omatch_var = (expr);    \
+        switch (_omatch_var.is_some())  \
+        {                               \
+            {                           \
+                {                       \
+    /*}}}}*/
+#define OMATCH_END()        \
+    /*{{{{*/                \
+                }           \
+            }               \
+        }                   \
+        (void) _omatch_var; \
+    }
+
+#define OMATCH_BEGIN_SOME(var, expr)    \
+    OMATCH_BEGIN (expr)                 \
+    OMATCH_CASE_SOME (var)
+
+#define OMATCH_CASE_SOME(var)                           \
+    /*{{{{*/                                            \
+        }                                               \
+        break;                                          \
+    }                                                   \
+    {                                                   \
+        case true:                                      \
+        {                                               \
+            auto&& var = *_omatch_var.ptr_or(nullptr);  \
+    /*}}}}*/
+#define OMATCH_CASE_NONE()  \
+    /*{{{{*/                \
+        }                   \
+        break;              \
+    }                       \
+    {                       \
+        case false:         \
+        {                   \
+    /*}}}}*/
 } // namespace option
 
 //using option::Option;
diff --git a/src/compat/option_test.cpp b/src/compat/option_test.cpp
index f9cec0e..69f3a60 100644
--- a/src/compat/option_test.cpp
+++ b/src/compat/option_test.cpp
@@ -398,24 +398,32 @@ TEST(Option, unwrap)
     v = None; TRY_UNWRAP(fcr(), v = Some(1));
 
     v = None;
-    if OPTION_IS_SOME_NOLOOP(o, v)
+    OMATCH_BEGIN (v)
     {
-        EXPECT_NE(o, o);
-    }
-    else
-    {
-        SUCCEED();
+        OMATCH_CASE_SOME (o)
+        {
+            EXPECT_NE(o, o);
+        }
+        OMATCH_CASE_NONE ()
+        {
+            SUCCEED();
+        }
     }
+    OMATCH_END ();
 
     v = Some(1);
-    if OPTION_IS_SOME_NOLOOP(o, v)
+    OMATCH_BEGIN (v)
     {
-        EXPECT_EQ(o, 1);
-    }
-    else
-    {
-        FAIL();
+        OMATCH_CASE_SOME (o)
+        {
+            EXPECT_EQ(o, 1);
+        }
+        OMATCH_CASE_NONE ()
+        {
+            FAIL();
+        }
     }
+    OMATCH_END ();
 }
 
 TEST(Option, flatten)