TPL

A compiler to generate template metaprograms in C++.

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About TPL

TPL is a language that is translated to C++ template metaprograms by its compiler. It simplifies creation of template metaprograms and showcases the computability abilities of the C++ template system. The compiler is implemented in Scala.

Supported Compilers

In theory TPL should support any Compiler that implements the C++ 17 ISO Standard correctly. In practice, most compiler don't do that, not even in conformance mode. The code the TPL compiler generates is tested to work on g++-11 with

g++-11 -ftemplate-depth=100000 -pedantic -Werror -std=c++17

Even g++ 11 does not implement C++ 17 entirely correct. TPL uses workarounds for these issues.

Getting Started

To use this project you first need to compile the compiler.

Prerequisites

To use TPL you need a working java installation. To build the TPL Compiler you also need Scala and SBT. Installation directions can be found here. Alternatively you can use IntelliJ to play around with it.

Building the Compiler

This can be done by executing

sbt assembly

in the root directly of this project. The compiler can then be found at target/scala-2.13/tpl.jar

Using the Compiler

The compiler can be executed with a java installation. It has the following options:

Usage: 'java -jar tpl.jar' [OPTIONS...]

Executes all compiler phases up to (and including) the specified one.
If no flag is specified, all phases are run and code is written to the output file.
Options:
  --in PATH                Add a folder or a file to the list of input files. Can be used any number of times.
  --out PATH               Specifies the path of the output folder. 
                           All generated files will be placed there.
  --parse                  Check just for syntactic correctness.
  --absyn                  Check for syntactic correctness and output the abstract syntax tree.
  --disable-optimization   Disables an optimization that reduces code size.

Running tests

There are a number of integration tests that check the correctness of the implementation. They can be started by running

sbt test

New tests can be added easily.

Using the library

This repository also contains a (admittedly small) library with some general purpose TPL Code. The folder stdlib can be added as an input folder with --in to any compiler invocation to allow your code to use the library.

Contributing

Any contributions you make are greatly appreciated. The project currently benefits the most from additional test cases. Tests are dynamically loaded from test files in the tests folder. Add a *.tpl File or a folder containing a test.tpl file for tests that need more than one source file. You can also supply a comment to the test file (or the test.tpl for folders) to specify an expected outcome:

// name: <any text> -- The name of the test case
// stdlib: <true|false> -- Whether to include the standard library when compiling this test
// outcome: <compilererror|compilersuccess|runtimeerror|success> -- The expected outcome when compiling/running this test case
// output: <any text> -- The compiler output for outcome=compilersuccess or the output of the executed program if outcome=success

Test cases are run with g++ 11 when outcome is either runtimeerror or success. A main function is included with src/test/ressources/test_main.cpp to prettify computed results and output them when outcome is success.