gencpp/project/Readme.md

# Documentation

The core library is contained within `gen.hpp` and `gen.cpp`.  
Things related to the editor and scanner are in their own respective files. (Ex: `gen.scanner.<hpp/cpp>` )

Dependencies are within `gen.dep.<hpp/cpp>`

The library is fragmented into a series of headers and sources files meant to be scanned in and then generated to a tailored format for the target
`gen` files.

Both libraries use *pre-generated* (self-hosting I guess) version of the library to then generate the latest version of itself.  
(sort of a verification that the generated version is equivalent)

The default `gen.bootstrap.cpp` located in the project folder is meant to be produce a standard segmented library, where the components of the library  
have relatively dedicated header and source files. With dependencies included at the top of the file and each header starting with a pragma once.  
This will overwrite the existing library implementation in the immediate directory.

Use those to get a general idea of how to make your own tailored version.

If the naming convention is undesired, the `gencpp.refactor` script can be used with the [refactor]()

Feature Macros:

* `GEN_DONT_USE_NAMESPACE` : By default, the library is wrapped in a `gen` namespace, this will disable that expose it to the global scope.
* `GEN_DONT_ENFORCE_GEN_TIME_GUARD` : By default, the library ( gen.hpp/ gen.cpp ) expects the macro `GEN_TIME` to be defined, this disables that.
* `GEN_ROLL_OWN_DEPENDENCIES` : Optional override so that user may define the dependencies themselves.
* `GEN_DEFINE_LIBRARY_CORE_CONSTANTS` : Optional typename codes as they are non-standard to C/C++ and not necessary to library usage
* `GEN_ENFORCE_STRONG_CODE_TYPES` : Enforces casts to filtered code types.
* `GEN_EXPOSE_BACKEND` : Will expose symbols meant for internal use only.
* `GEN_Define_Attribute_Tokens` : Allows user to define their own attribute macros for use in parsing.

`GEN_USE_RECURSIVE_AST_DUPLICATION` is available but its not well tested and should not need to be used.  
If constructing ASTs properly. There should be no modification of ASTs, and thus this would never become an issue.  
(I will probably remove down the line...)

## On multi-threading

Currently unsupported. The following changes would have to be made:

* Setup static data access with fences if more than one thread will generate ASTs ( or keep a different set for each thread)
* Make sure local persistent data of functions are also thread local.
* The builder should be done on a per-thread basis.
* Due to the design of the editor and scanner, it will most likely be best to make each file a job to process request entries on. Receipts should have an an array to store per thread. They can be combined to the final receipts array when all files have been processed.

## Extending the library

This library is relatively very small, and can be extended without much hassle.

The convention you'll see used throughout the API of the library is as follows:

1. Check name or parameters to make sure they are valid for the construction requested
2. Create a code object using `make_code`.
3. Populate immediate fields (Name, Type, ModuleFlags, etc)
4. Populate sub-entires using `add_entry`. If using the default serialization function `to_string`, follow the order at which entires are expected to appear (there is a strong ordering expected).

Names or Content fields are interned strings and thus showed be cached using `get_cached_string` if its desired to preserve that behavior.

`def_operator` is the most sophisticated constructor as it has multiple permutations of definitions that could be created that are not trivial to determine if valid.

The library has its code segmented into component files, use it to help create a derived version without needing to have to rewrite a generated file directly or build on top of the header via composition or inheritance.
When the scanner is implemented, this will be even easier to customize.