Project Trieste is a term rewriting system designed for rapidly prototyping programming languages. Trieste provides three C++ DSLs to enable the rapid prototyping:

• Parsing - Enables generation of an untyped abstract syntax tree (AST) from one or many input files.
• Rewriting - Enables the restructuring and analysis of the AST. It can be used to simplify, elaborate to alternative representations, and lower to backend IRs or bytecodes.
• Well-formedness - Trieste provides a DSL for checking that the current AST conforms to a specification.

Using the well-formedness definitions Trieste can rapidly harden a language by automatically checking conformance to the specification. Additionally, Trieste uses the well-formedness definitions to generate test cases to fuzz each rewriting pass conforms with its specification.

If you want to dive right into understanding how to use Trieste, take a look at the infix tutorial language, which will walk you through implementing a simple calculator language in Trieste.

Trieste is a header-only C++20 library. To get started, you'll need to define your own trieste::Driver, and run it from main:

#include <trieste/driver.h>

int main(int argc, char** argv)
{
  // Define your driver...
  trieste::Driver driver(...);
  return driver.run(argc, argv);
}

Here's an example of how to build the infix sample and run the self-tests. Other build systems and compilers may work as well.

git clone https://github.com/microsoft/trieste
cd trieste
mkdir build
cd build
cmake -G Ninja .. -DCMAKE_BUILD_TYPE=Debug -DCMAKE_CXX_COMPILER=clang++-14
ninja install
./dist/infix/infix test

Trieste includes an opt-in benchmark that compares the internal regex engine against RE2.

• Option: TRIESTE_BUILD_REGEX_BENCHMARK
• Default: OFF
• RE2 is fetched and built only when this option is enabled.
• The benchmark target is not added to ctest.

Default behavior (no benchmark, no RE2 fetch/build):

cmake -S . -B build-default
cmake --build build-default

Benchmark-enabled behavior:

cmake -S . -B build-bench \
  -DTRIESTE_ENABLE_TESTING=ON \
  -DTRIESTE_BUILD_REGEX_BENCHMARK=ON
cmake --build build-bench --target trieste_regex_engine_benchmark
./build-bench/test/trieste_regex_engine_benchmark

The benchmark output includes deterministic workload metadata and summary ratios for compile+match and match-only timings.

Regex syntax policy for strict iregexp (RFC9485) compatibility versus extended Trieste behavior is defined in notes/regex-syntax-policy.md.

You can use Trieste via FetchContent by including the following lines in your CMake:

FetchContent_Declare(
  trieste
  GIT_REPOSITORY https://github.com/microsoft/Trieste
  GIT_TAG        a2a7fada4ab5250a4f8d1313b749ad336202841b
)

FetchContent_MakeAvailable(trieste)

And then adding it as a target link library, e.g.

target_link_libraries(verona
  Threads::Threads
  CLI11::CLI11
  trieste::trieste
  )

If you are interested in contributing to Trieste, please see our contributing document.