cel-std

cel-std installs numeric operations into the C++ CEL parser for execution by CEL runtime. Use it when your C++ application needs CEL expressions such as clamp(sqrt(9.0), 0.0, 4.0).

This port retains 35 Rust cel-std operations with f64 (double) operands. It excludes powi, all integer overloads, and all f32 overloads. sin_cos returns a CEL (f64, f64) tuple. Ordinary and receiver calls use the same registrations.

Add the library

Use C++20 and CMake 3.24 or later. After loading CPM, add the library to your project:

CPMAddPackage("gh:stlab/[email protected]")
target_link_libraries(your_app PRIVATE cel::std)

Replace your_app with your executable target. The library brings in compatible, pinned parser and runtime dependencies.

Include <cel/std.hpp> and <cel/parser/compiler.hpp>, create a cel::op_lookup, and call cel::stdlib::install(lookup) before transferring the lookup into a parser. See the tutorial for a complete, compiled example and installed-package instructions.

Build and test

Configure, build, and run all unit, example, and consumer tests:

cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug -DBUILD_DOCS=OFF
cmake --build build --parallel
ctest --test-dir build --output-on-failure

Generate the tutorial and API reference with Doxygen 1.13.1 or later:

cmake -S . -B build/docs -DBUILD_DOCS=ON -DBUILD_TESTING=OFF
cmake --build build/docs --target docs

Open build/docs/html/index.html.

Documentation

The tutorial teaches installation, parsing, execution, and tuple results. The reference lists the C++ interface and retained signatures. For operation behavior and examples, see the CEL language book's standard library. The book also covers Rust types and powi that this port does not provide.

The implementation uses the C++ standard library and small adapters for Rust semantics. Build without fast-math modes that discard NaNs, signed zeros, or IEEE arithmetic. Approximate transcendental results can differ across standard libraries; NaN payloads are not part of the contract.

License

Boost Software License 1.0. The CPM bootstrap is MIT-licensed; see licenses/CPM-MIT.txt.