Implemented relational operators for Point. (#207)

* Implemented relational operators for Point. Used the Boost.Operators mechanism to implement it. Also refactored existing +,- operators to work in terms of that. * Reimplemented less-operator for point std::tie is not constepxr on Travis, so this has to be factored out for now.
KazDragon · Aug 26, 2019 · fe7b0e3 · fe7b0e3
1 parent 55459a0
commit fe7b0e3
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Showing 2 changed files with 62 additions and 22 deletions.
diff --git a/include/terminalpp/point.hpp b/include/terminalpp/point.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include "terminalpp/core.hpp"
+#include <boost/operators.hpp>
 #include <iosfwd>
 
 namespace terminalpp {
@@ -13,6 +14,10 @@ namespace terminalpp {
 /// axis.
 //* =========================================================================
 struct point
+  : private boost::less_than_comparable<point,
+            boost::equality_comparable<point,
+            boost::addable<point,
+            boost::subtractable<point>>>>
 {
     //* =====================================================================
     /// \brief Default Constructor
@@ -62,35 +67,21 @@ struct point
 };
 
 // ==========================================================================
-// OPERATOR==(POINT,POINT)
-// ==========================================================================
-constexpr bool operator==(point const &lhs, point const &rhs)
-{
-    return lhs.x == rhs.x && lhs.y == rhs.y;
-}
-
-// ==========================================================================
-// OPERATOR!=(POINT,POINT)
+// OPERATOR<(POINT,POINT)
 // ==========================================================================
-constexpr bool operator!=(point const &lhs, point const &rhs)
+constexpr bool operator<(point const &lhs, point const &rhs)
 {
-    return !(lhs == rhs);
+    // Note: reimplemented due to std::tie not being constexpr everywhere.
+    return lhs.y < rhs.y
+        || (lhs.y == rhs.y && lhs.x < rhs.x);
 }
 
 // ==========================================================================
-// OPERATOR+(POINT,POINT)
-// ==========================================================================
-constexpr point operator+(point lhs, point const &rhs)
-{
-    return lhs += rhs;
-}
-
-// ==========================================================================
-// OPERATOR-(POINT,POINT)
+// OPERATOR==(POINT,POINT)
 // ==========================================================================
-constexpr point operator-(point lhs, point const &rhs)
+constexpr bool operator==(point const &lhs, point const &rhs)
 {
-    return lhs -= rhs;
+    return lhs.x == rhs.x && lhs.y == rhs.y;
 }
 
 //* =====================================================================

diff --git a/test/point_test.cpp b/test/point_test.cpp
@@ -34,3 +34,52 @@ INSTANTIATE_TEST_CASE_P(
         point_string{ {-4, 63},         "point(-4,63)" },
         point_string{ {96583, 1231234}, "point(96583,1231234)" }
     }));
+
+using point_relops_data = std::tuple<
+    terminalpp::point, // lhs
+    terminalpp::point, // rhs
+    bool, // less
+    bool, // less-equal
+    bool, // equal
+    bool, // greater-equal
+    bool  // greater
+>;
+
+class points_compare : public testing::TestWithParam<point_relops_data>
+{
+};
+
+TEST_P(points_compare, according_to_relops)
+{
+    auto const &param = GetParam();
+    auto const &lhs = std::get<0>(param);
+    auto const &rhs = std::get<1>(param);
+    auto const &less = std::get<2>(param);
+    auto const &less_equal = std::get<3>(param);
+    auto const &equal = std::get<4>(param);
+    auto const &greater_equal = std::get<5>(param);
+    auto const &greater = std::get<6>(param);
+
+    ASSERT_EQ(less, lhs < rhs);
+    ASSERT_EQ(less_equal, lhs <= rhs);
+    ASSERT_EQ(equal, lhs == rhs);
+    ASSERT_EQ(!equal, lhs != rhs);
+    ASSERT_EQ(greater_equal, lhs >= rhs);
+    ASSERT_EQ(greater, lhs > rhs);
+}
+
+INSTANTIATE_TEST_CASE_P(
+    using_relational_operators,
+    points_compare,
+    ValuesIn(std::vector<point_relops_data>{
+        point_relops_data{{0, 0}, {1, 1}, true,  true,  false, false, false },
+        point_relops_data{{1, 0}, {1, 1}, true,  true,  false, false, false },
+        point_relops_data{{2, 0}, {1, 1}, true,  true,  false, false, false },
+        point_relops_data{{0, 1}, {1, 1}, true,  true,  false, false, false },
+        point_relops_data{{1, 1}, {1, 1}, false, true,  true,  true,  false },
+        point_relops_data{{2, 1}, {1, 1}, false, false, false, true,  true  },
+        point_relops_data{{0, 2}, {1, 1}, false, false, false, true,  true  },
+        point_relops_data{{1, 2}, {1, 1}, false, false, false, true,  true  },
+        point_relops_data{{2, 2}, {1, 1}, false, false, false, true,  true  }
+    }));
+