Merge branch 'infix' into develop

include/fit/infix.hpp

@@ -27,7 +27,7 @@
 /// Semantics
 /// ---------
 /// 
-///     assert((x <infix(f)> y) == f(x, y));
+///     assert(x <infix(f)> y == f(x, y));
 /// 
 /// Requirements
 /// ------------
@@ -37,6 +37,24 @@
 /// * [BinaryCallable](BinaryCallable)
 /// * MoveConstructible
 /// 
+/// Operator precedence
+/// -------------------
+/// 
+/// Infix operators have the precedence of relational operators. This means
+/// operators such as `+` or `*` have higher precedence:
+/// 
+///     assert((x + y <infix(f)> z) == ((x + y) <infix(f)> z));
+///     assert((x * y <infix(f)> z) == ((x * y) <infix(f)> z));
+/// 
+/// However, operators such as `|` or `==` have lower precedence::
+/// 
+///     assert((x | y <infix(f)> z) == (x | (y <infix(f)> z)));
+///     assert((x == y <infix(f)> z) == (x == (y <infix(f)> z)));
+/// 
+/// Also, infix operators have left-to-right associativity:
+/// 
+///     assert(x <infix(f)> y <infix(g)> z == ((x <infix(f)> y) <infix(g)> z));
+/// 
 /// Example
 /// -------
 /// 

test/infix.cpp

@@ -1,6 +1,7 @@
 #include <fit/infix.hpp>
 #include <fit/function.hpp>
 #include <fit/lambda.hpp>
+#include <fit/pipable.hpp>
 #include <fit/placeholders.hpp>
 #include "test.hpp"
 
@@ -83,3 +84,26 @@ FIT_TEST_CASE()
     FIT_TEST_CHECK(3 == (sum5(1, 2)));
     FIT_STATIC_TEST_CHECK(3 == (sum5(1, 2)));
 }
+
+FIT_TEST_CASE()
+{
+#if (defined(__GNUC__) && !defined (__clang__))
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wparentheses"
+#endif
+    FIT_TEST_CHECK(6 == (1 + 2 <sum> 3));
+    FIT_TEST_CHECK(3 == 1 <sum> 2);
+#if (defined(__GNUC__) && !defined (__clang__))
+#pragma GCC diagnostic pop
+#endif
+}
+
+struct foo {};
+
+FIT_TEST_CASE()
+{
+    auto f = fit::infix([](int, int) { return foo{}; });
+    auto g = fit::infix([](foo, foo) { return std::string("hello"); });
+    FIT_TEST_CHECK((1 <f> 2 <g> foo{}) == "hello");
+
+}