Custom generator

Silvera allows users to register new code generators as plugins.

Silvera uses the pkg_resources module from setuptools and its concept of extension point to declaratively specify the registration of the new code generator. Extensions are defined within the project's setup.py module. All Python projects installed in the environment that declare the extension point will be discoverable dynamically.

Registration of a new code generator is performed in two steps (as shown below). You can also follow the video tutorial:

There is also a demo application where this functionality is demonstrated: PyGen

Step 1

Create an instance of GeneratorDesc class. An instance of GeneratorDesc class contains information about the code generator's target language, description, and the reference towards the function that should be called to perform code generation. This function has three parameters: Decl object, a path to the directory where code will be generated, and a flag that shows whether the code generator is run in debug mode.

from silvera.generator.gen_reg import GeneratorDesc

def generate(decl, output_dir, debug):
    """Entry point function for code generator.

    Args:
        decl(Decl): can be declaration of service registry or config
                    server.
        output_dir(str): output directory.
        debug(bool): True if debug mode activated. False otherwise.
    """
    ...

python = GeneratorDesc(
    language_name="python",
    language_ver="3.7.4",
    description="Python 3.7.4 code generator",
    gen_func=generate
)

Step 2

Now, we need to make the code generator discoverable by Silvera. To do this, we must register the GeneratorDesc object in the setup.py entry point named silvera_generators:

# setup.py

from setuptools import setup

setup(
    ...
    entry_points={
        'silvera_generators': [
            'python = pygen.generator:python'
        ]
    }
)