temppy

A header-only, template metaprogramming "Python-esque" interpreter that runs entirely at compile time.

Highlights

• C++23 compile-time lexing, parsing, and evaluation
• Arithmetic with precedence and parentheses
• Variables and multi-line assignments
• Unary + / unary -
• # comments
• String-literal program syntax via "_s"

Build (CMake)

Prereqs:

• A C++23 compiler (GCC 13+ or Clang 16+ recommended)
• CMake 3.20+

cmake -S . -B build/cmake
cmake --build build/cmake
ctest --test-dir build/cmake --output-on-failure

Build (Makefile)

make run-examples
make run-tests

Quick Start

#include "temppy/temppy.hpp"
#include <iostream>

int main() {
    using program = decltype(
        "x = -5\n"
        "# comments are supported\n"
        "y = x * -2\n"
        "y"_s);

    using result = temppy::Run<program>;

    static_assert(result::value::value == 10);
    std::cout << result::value::value << "\n";
}

Looking up variables from the final environment:

using x_value = temppy::Lookup_t<typename result::env, temppy::String<'x'>>;
static_assert(x_value::value == -5);

Project Layout

• include/temppy/: header-only library
• examples/: runnable examples (including language_features.cpp)
• tests/: compile-time/static-assert based smoke tests