Example build

To build Bakery:

cd python;
nix-shell;
python -m tako.main generate bakery_test/ test_types.bakery.Bakery cpp

Notes on design

The code makes a lot of references to "Root{Type, Visitor, etc.}" as compared to "{Type, Visitor, etc.}".

The difference, as far as I can tell, is that RootTypes are able to be declared in a protocol's top level.

This includes:

• Enum
• Struct
• Variant
• HashVariant

Regular Types include:

• int
• float
• seq
• detached_variant ( not totally sure why )
• virtual

Basic Flow ( could be issues, this is an evolving code archaeology )

Step	Description	Key Files
Main	Primary entrypoint via main. Very little code is run before dispatching to compiler.	main.py
Ingest / Parsing	Code related to sanity and type checking, making sure root types are respected. The compile_proto function walks through the process of steadily lowering IRs down to the final SIR ( which is just a structification of the LIR ). It does this independently for types, constants, and conversions. In below cells we'll only discuss types, as that's the most complex case, but others follow a similar pattern.	compiler/__init__.py::compile_proto in compile.py and subsequently ingest.py::run
MIR Construction from Ingest	Take the inputs which are still in a fairly raw format and lower them to MIR through lower.py.	types/__init__.py::compile lower.py
Hash Expansion	Hash Variants ( which dont store tag values ) are expanded into FixedVariants and the values are thereafter fixed. Collisions are resolved here.	hash_expand.py
LIR Construction from MIR	Series of expansions happen, for example, variants are turned into a determinant tag and a payload. This is all proeparatory work for fuse.py, which ultimately lowers us down to lir properly. Fuse is doing a lot of data enriching to get us ready to generate code, annotating with notions of triviality, digests, and more.	fuse.py lir.py
Construct SIR from LIR	Back up in compiler/__init__.py this is a trivial step to hold everything in a single struct, afaict.	sir.py compiler/__init__.py
Generate target language	Operate on the SIR to do code generation.	cpp.py::generate_into