Various doc updates.

CMakeLists.txt

@@ -294,6 +294,10 @@ target_compile_features(obake PUBLIC cxx_std_20)
 # Ensure vanilla C++ is being used.
 set_property(TARGET obake PROPERTY CXX_EXTENSIONS NO)
 if(YACMA_COMPILER_IS_MSVC)
+    # NOTE: older abseil versions have a problem on MSVC
+    # when using C++20:
+    # https://github.com/abseil/abseil-cpp/issues/649
+    # Hopefully we can eventually remove this.
     target_compile_definitions(obake PUBLIC -D_HAS_DEPRECATED_RESULT_OF=1)
 endif()
 

README.md

@@ -1,4 +1,4 @@
-![language](https://img.shields.io/badge/language-C%2B%2B17-red.svg?style=for-the-badge)
+![language](https://img.shields.io/badge/language-C%2B%2B20-green.svg?style=for-the-badge)
 [![Linux Build Status](https://img.shields.io/circleci/project/github/bluescarni/obake/master.svg?style=for-the-badge)](https://circleci.com/gh/bluescarni/obake)
 [![Windows Build Status](https://img.shields.io/appveyor/ci/bluescarni/obake/master.svg?logo=appveyor&style=for-the-badge)](https://ci.appveyor.com/project/bluescarni/obake)
 [![OSX Build Status](https://img.shields.io/travis/bluescarni/obake/master.svg?logo=travis&style=for-the-badge)](https://travis-ci.org/bluescarni/obake)
@@ -13,7 +13,7 @@
 > Literally, the terms mean a thing that changes, referring to a state of transformation
 > or shapeshifting.
 
-obake is a C++17 library for the symbolic manipulation of sparse polynomials
+obake is a C++20 library for the symbolic manipulation of sparse polynomials
 and other closely-related mathematical objects (e.g., truncated power
 series, Poisson series, etc.). obake is the successor of the
 [piranha](https://github.com/bluescarni/piranha) project.

doc/install.rst

@@ -25,23 +25,22 @@ obake also depends on other libraries for optional features:
 Installation from source
 ------------------------
 
-obake is written in `C++17 <https://en.wikipedia.org/wiki/C%2B%2B17>`_,
+obake is written in `C++20 <https://en.wikipedia.org/wiki/C%2B%2B20>`_,
 and thus it requires a fairly recent compiler with
 robust support for modern C++ idioms. The following compilers are regularly
 tested in obake's continuous integration setup:
 
-* GCC 7 and 8 on Linux (Ubuntu bionic and cosmic),
-* Clang 6 and 7 on Linux (Ubuntu bionic and cosmic),
+* GCC 9 on Linux (Ubuntu Focal),
 * Visual Studio 2019 on Windows,
-* Clang + Visual Studio 2017 on Windows
+* Clang 11 + Visual Studio 2017 on Windows
   (via the ``clang-cl`` driver),
-* Clang 9 on OSX.
+* Clang 11 on OSX.
 
 See also the
 :ref:`compiler and platform specific notes <platform_specific_notes>`.
 
 In order to install obake from source, `CMake <https://cmake.org/>`_ is
-required (at least version 3.8). After downloading and unpacking obake's
+required (at least version 3.12). After downloading and unpacking obake's
 source code, go to obake's
 source tree, create a ``build`` directory and ``cd`` into it. E.g.,
 on a Unix-like system:
@@ -117,7 +116,7 @@ If enabled, the test suite can be executed with the command:
 Troubleshooting
 ^^^^^^^^^^^^^^^
 
-By far, the most common problem when compiling obake is the detection
+The most common problem when compiling obake is the detection
 of the dependencies.
 
 On Linux systems, generally speaking, the best way of installing the
@@ -156,20 +155,9 @@ Visual Studio:
   with the ``NOMINMAX`` and ``WIN32_LEAN_AND_MEAN`` definitions,
   and, if supported, with the ``/permissive-`` compiler flag.
 
-GCC:
-
-* Due to a compiler bug, when using GCC 7 obake's customisation points
-  do not have any ``noexcept`` specifier.
-
-Clang:
-
-* Due to a compiler bug, Clang 8.0.0 may fail to compile obake's
-  test suite with debugging information. The issue appears to have been
-  rectified in Clang 8.0.1.
-
 OSX:
 
-* On OSX, only the most recent versions of Xcode (i.e., Xcode 9 or later)
+* On OSX, only the most recent versions of Xcode
   are capable of compiling obake.
   As an alternative to Xcode, one can install a more modern compiler toolchain
   using package managers such as `Conda <https://docs.conda.io/en/latest/>`_ or

include/obake/detail/xoroshiro128_plus.hpp

@@ -82,11 +82,8 @@ struct xoroshiro128_plus {
         }
 
         // Cast back to the original type.
-        // NOTE: in case Int is signed, this operation is
-        // implementation-defined up to C++20, and from C++20
-        // this follows the rules of two's complement arithmetic.
-        // In practice, all implementations follow two's complement
-        // even before C++20.
+        // NOTE: since C++20 this follows the rules of
+        // two's complement arithmetic.
         return static_cast<Int>(u_retval);
     }