ms-gsl dependency added to handle Expects (resolves #132)

conanfile.py

@@ -46,7 +46,8 @@ class UnitsConan(ConanFile):
     exports_sources = ["docs/*", "src/*", "test/*", "cmake/*", "example/*","CMakeLists.txt"]
     settings = "os", "compiler", "build_type", "arch"
     requires = (
-        "fmt/6.2.1"
+        "fmt/6.2.1",
+        "ms-gsl/3.1.0"
     )
     # scm = {
     #     "type": "git",

docs/usage.rst

@@ -16,7 +16,8 @@ This repository contains three independent CMake-based projects:
   - header-only project containing whole **mp-units** library
   - when C++20 support will be fully supported by C++ compilers this library will have
     no external dependencies but until then it depends on
-    `range-v3 <https://github.com/ericniebler/range-v3>`_ (only for gcc versions < 10.0)
+    `range-v3 <https://github.com/ericniebler/range-v3>`_ (only for gcc versions < 10.0),
+    `ms-gsl <https://github.com/microsoft/GSL>`_,
     and `{fmt} <https://github.com/fmtlib/fmt>`_ libraries.
 
 - *.*

src/CMakeLists.txt

@@ -56,6 +56,7 @@ target_compile_features(units INTERFACE cxx_std_20)
 target_link_libraries(units
     INTERFACE
         $<IF:$<TARGET_EXISTS:CONAN_PKG::fmt>,CONAN_PKG::fmt,fmt::fmt>
+        $<IF:$<TARGET_EXISTS:CONAN_PKG::ms-gsl>,CONAN_PKG::ms-gsl,Microsoft.GSL::GSL>
 )
 target_include_directories(units
     INTERFACE

src/include/units/bits/ratio_maths.h

@@ -30,6 +30,7 @@
 #include <numeric>
 #include <tuple>
 #include <type_traits>
+#include <gsl/gsl>
 
 namespace units::detail {
 

src/include/units/symbol_text.h

@@ -2,6 +2,7 @@
 
 #include <units/bits/external/fixed_string.h>
 #include <units/bits/external/hacks.h>
+#include <gsl/gsl>
 
 namespace units {
 

test/metabench/make_dimension/hacks.h

@@ -24,13 +24,6 @@
 
 #include <concepts/concepts.hpp>
 
-#ifdef NDEBUG
-#define Expects(cond) (void)(cond);
-#else
-#include <cassert>
-#define Expects(cond) assert(cond);
-#endif
-
 namespace std {
 
   // concepts