{0 stanc3 Developer Documentation}

This document provides the documentation for the internals of the stanc3
compiler {b intended for developers}.

If you are looking for the user-facing documentation, see
{{:https://mc-stan.org/docs/stan-users-guide/using-the-stan-compiler.html}
this section} of the Stan User's Guide.

{1 Getting Started}

See {{!page-getting_started}the Getting Started page} for information on setting up a stanc3 development environment.

{2 Resources}
Here are some resources (internal and external) which may be useful
to a new developer.

- {{:https://dev.realworldocaml.org/} Real World OCaml}, a free introduction to the OCaml language which features some
  of the libraries we use.

- {{!page-core_ideas} An overview of some elements of Stanc which may be strange to existing OCaml developers}.

- {{:https://github.com/stan-dev/stanc3/wiki/Format---Fmt-code-generation-quickstart}
  Wiki on using [Format]/[Fmt] module}

- {{!page-parser_messages}
  Page on modifying the parser's error messages}

- {{!page-exposing_new_functions}
  Page on exposing a new function of the Stan Math library}

- {{!page-cpp_ir}
  Page on how we implement C++ code generation with a structured type and mini-DSL}

- {{:https://github.com/stan-dev/stanc3/wiki/Software-Engineering-best-practices}
  Wiki on generic software best practices}

{2 Getting Involved}

- Here are {{:https://github.com/stan-dev/stanc3/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22}
  some good issues to tackle} - make sure to comment on them first to see if
  they are still relevant.
- We also always appreciated more documentation - either this documentation, which uses
  {{:https://ocaml.github.io/odoc/index.html}odoc}, or the Stan user-facing documentation
  at {{:https://github.com/stan-dev/docs}stan-dev/docs}.


{1 Modules}
The major code sections of the compiler are as follows (these are links):

{!modules:
Driver
Frontend
Middle
Common
Analysis_and_optimization
Stan_math_signatures
Stan_math_backend
}

These are related in the following architecture diagram

{%html: <img src="https://github.com/stan-dev/stanc3/raw/master/docs/img/architecture.png"/> %}

We additionally use several {{!page-dependencies} outside dependencies}.

