catala

Compiler and library for the literate programming language for tax code specification
IN THIS PACKAGE

The Catala compiler

Architecture

The architecture of the Catala compiler is inspired by CompCert or the Nanopass framework, and is structured around many intermediate representations connected by successive translations passes.

Here is the recap picture of the different intermediate representations of the Catala compiler (made with an ASCII diagram tool):

                                     +---------------+
                                     |               |
                                     |  Surface AST  |
                                     |               |
                                     +---------------+
                                             |
                                             |
         * Separate code from legislation    |
         * Remove syntactic sugars           |
                                             v
                                   +------------------+
                                   |                  |
                                   |  Desugared AST   |
                                   |                  |
                                   +------------------+
                                             |
                                             |
 * Build rule trees for each definition      |
 * Order variable computations inside scope  |
                                             v
                                  +--------------------+
                                  |                    |
                                  | Scope language AST |
                                  |                    |
                                  +--------------------+
                                             |
                                             |
        * Convert scopes into functions      |
        * Thunking of subscope arguments     |
                                             |
                                             v
                                 +----------------------+
                                 |                      |
                                 | Default calculus AST |
                                 |                      |
                                 +----------------------+
                                             |
                                             |
                                             |
       * Compile the default term            |
                                             |
                                             v
                                 +----------------------+
                                 |                      |
                                 | Lambda calculus AST  |
                                 |                      |
                                 +----------------------+
                                             |
                                             |
        * Turn expressions into statements   |
                                             |
                                             v
                               +--------------------------+
                               |                          |
                               |  Statement calculus AST  |
                               |                          |
                               +--------------------------+

List of top-level modules

Each of those intermediate representation is bundled into its own dune bundle module. Click on the items below if you want to dive straight into the signatures.

More documentation can be found on each intermediate representations here.

The main compilation chain is defined in:

Additionally, the compiler features a verification plugin that generates verification condition for proof backends. More information can be found here:

Two more modules contain additional features for the compiler:

The Catala runtimes documentation is available here:

Last, it is possible to customize the backend to the compiler using a plugin mechanism. The API is defined inside the following module:

See the examples in the plugins/ subdirectory: