From 715b0fe840d1563ee045a882a06d8cd458aff3b9 Mon Sep 17 00:00:00 2001
From: Stefano Sanfilippo <a.little.coder@gmail.com>
Date: Wed, 10 Dec 2014 23:02:55 +0100
Subject: [PATCH] Compiler features discovery and Bison version check.

---
 CMakeLists.txt                     | 36 ++++++++++++++++++++-
 bison2.patch => cmake/bison2.patch |  0
 cmake/features.cpp                 | 52 ++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+), 1 deletion(-)
 rename bison2.patch => cmake/bison2.patch (100%)
 create mode 100644 cmake/features.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3be8b9e..6d95090 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,8 +20,42 @@
 project(Monicelli)
 cmake_minimum_required(VERSION 2.8)
 
+message("== Only a limited set of platforms was tested. We need your help!")
+message("== Report build errors to https://github.com/esseks/monicelli/issues")
+
+## 1. Compiler sanity check
+
+try_compile(
+    supported_compiler
+    ${CMAKE_CURRENT_BINARY_DIR}
+    ${CMAKE_CURRENT_SOURCE_DIR}/cmake/features.cpp
+    COMPILE_DEFINITIONS -std=c++0x
+    OUTPUT_VARIABLE features_build_log
+)
+
+if (checkfeat)
+    message(${features_build_log})
+endif()
+
+if (NOT supported_compiler)
+    message(FATAL_ERROR
+        "Some C++11 features we need are not implemented by your compiler.\n"
+        "Run cmake with -Dcheckfeat=1 to see the exact cause."
+    )
+endif()
+
+## 2. Find Flex and Bison
+
 find_package(BISON REQUIRED)
-find_package(FLEX REQUIRED)
+find_package(FLEX 2.5 REQUIRED)
+
+if (BISON_VERSION VERSION_LESS 2.5)
+    message(FATAL_ERROR "At least Bison 2.5 is required.")
+elseif(BISON_VERSION VERSION_LESS 3.0)
+    message("== Bison 2.5 was found. You have to apply cmake/bison2.patch...")
+endif()
+
+## 3. Build
 
 include_directories(
     ${CMAKE_CURRENT_BINARY_DIR}
diff --git a/bison2.patch b/cmake/bison2.patch
similarity index 100%
rename from bison2.patch
rename to cmake/bison2.patch
diff --git a/cmake/features.cpp b/cmake/features.cpp
new file mode 100644
index 0000000..051ba0e
--- /dev/null
+++ b/cmake/features.cpp
@@ -0,0 +1,52 @@
+/*
+ * Monicelli: an esoteric language compiler
+ * 
+ * Copyright (C) 2014 Stefano Sanfilippo
+ *
+ * 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/>.
+ */
+
+/**
+ * Minimum program containing all required C++11 features.
+ * If a compiler cannot compile this, then it won't compile Monicelli.
+ */
+
+#include <memory>
+#include <unordered_set>
+#include <functional>
+
+#include <vector>
+#include <string>
+
+enum class Dummy {
+    FOO, BAR, BAZ
+};
+
+class Banana {
+    int yep() const noexcept {
+        return 0;
+    }
+};
+
+int main() {
+    std::unique_ptr<int> foo(new int{0});
+    std::vector<int> bar = {1, 2, 3};
+    for (int baz: bar) {
+        baz += 1;
+    }
+    char *str = nullptr;
+    Banana a;
+    Banana b = std::move(a);
+    long c = std::stol("100");
+}