C++ Preprocessor Library¶
Primitives for abusing using the preprocessor in a structured fashion.
Brief Tour¶
Using the C preprocessor to generate code, while often derided, is
sometimes useful. The pp library is light-weight, header-only macro
library providing primitives such as lists, sequences, conditionals
and map operations, designed to facilitate using the C preprocessor
in a well-structured, functional manner.
The following snippet demonstrates generating class template instatiations for several types.
#include "core/pp/pp.h"
#define GEN_MYCLASS(N,T) template<> class N<T>;
#define GEN_MYCLASS_SEQ(SEQ) CORE_PP_EVAL_MAP_WITH_SEQ(MYCLASS,MyClass,SEQ)
#define TYPE_SEQ (int8, int16, int32, int64)
GEN_MYCLASS_SEQ(TYPE_SEQ)
Produces the following:
template<> class MyClass<int>; template<> class MyClass<long int>; template<> class MyClass<unsigned int>;
Yes, I know, if only we could get the proprocessor to emit some newlines. Like I said, don’t go there unless you must.
Installation¶
git clone https://github.com/cpp-core/pp
mkdir pp/build && cd pp/build
CC=clang-mp-16 CXX=clang++-mp-16 cmake -DCMAKE_INSTALL_PREFIX=$HOME/opt ..
make -j4 check # Run tests
make install # Do the install
To build the documentation (requires doxygen and sphinx-build to be installed)::
CC=clang-11 CXX=clang++11 cmake -DCORE_DOCS ..
make cxx_core_pp_docs # root of html tree is docs/html/index.html
Background¶
cxx-core-pp is part of the cxx-core* family of C++20 based libraries. The cxx-core libraries have two primary goals:
Ergonomics. In the spirit of the
CppCoreGuideLines, cxx-core aspires to facilitate writing concise, idiomatic code not by force, but by providing a clear path that produces robust, easy to read code. Good code should be fun to write.Components. Modern language platforms provide broad support for first-class library components, while C++ has traditionally only provided a very minimal standard library. cxx-core aspires to provide support for a broad range of libraries that feel like part of the language.
License¶
This software is licensed under the BSD 3-clause license. See the LICENSE file for details.
Appendix¶
API REFERENCE