pyfcstm.render.render

State machine code renderer for Jinja2 template-based code generation.

This module provides the StateMachineCodeRenderer class, which renders state machine models into code files using a template directory. The renderer supports configuration-driven expression styles, Jinja2 globals, filters, and tests. Template files with the .j2 extension are rendered, while all other files are copied directly to the output directory.

The template directory is expected to contain:

  • config.yaml - Configuration file for the renderer (see below)

  • *.j2 files - Jinja2 templates to render

  • Other files - Copied verbatim to the output directory

Configuration file (config.yaml) structure:

  • expr_styles - Mapping of expression rendering styles. Each style is a mapping with a base_lang key and optional template overrides. The default style is always created if absent.

  • stmt_styles - Mapping of statement rendering styles. Each style is a mapping with a base_lang key and optional overrides such as declare_temp and temp_type_aliases for static-language backends.

  • globals - Mapping of Jinja2 globals (see pyfcstm.render.func.process_item_to_object())

  • filters - Mapping of Jinja2 filters (same structure as globals)

  • tests - Mapping of Jinja2 tests (same structure as globals)

  • ignores - Git-style ignore patterns to skip files in the template directory

Expression rendering:

  • Use {{ expression | expr_render }} to render with the default style

  • Use {{ expression | expr_render(style='c') }} to render with a named style

The module depends on jinja2, pyyaml, and pathspec for templating, YAML configuration, and ignore pattern handling.

Example:

>>> from pyfcstm.render.render import StateMachineCodeRenderer
>>> from pyfcstm.model import StateMachine
>>> renderer = StateMachineCodeRenderer('./templates')
>>> renderer.render(StateMachine(defines={}, root_state=some_state), './output')

StateMachineCodeRenderer

class pyfcstm.render.render.StateMachineCodeRenderer(template_dir: str, config_file: str = 'config.yaml')[source]

Renderer for generating code from state machine models using templates.

This class handles rendering of state machine models into code by combining a template directory with a configuration file. It creates a Jinja2 environment, registers expression rendering styles, and maps template files to rendering operations or file copying operations.

Parameters:

  • template_dir (str) – Directory containing the templates and configuration

  • config_file (str, optional) – Name of the configuration file within the template directory, defaults to 'config.yaml'

Variables:

  • template_dir (str) – Absolute path to the template directory

  • config_file (str) – Absolute path to the configuration file

  • env (jinja2.Environment) – Jinja2 environment used for rendering

  • _ignore_patterns (List[str]) – List of git-style ignore patterns

  • _file_mappings (Dict[str, Callable]) – Mapping of relative template paths to render/copy callables

Example:

>>> renderer = StateMachineCodeRenderer('./templates')
>>> renderer.render(my_state_machine, './output', clear_previous_directory=True)
__init__(template_dir: str, config_file: str = 'config.yaml') → None[source]

Initialize the StateMachineCodeRenderer.

Parameters:

  • template_dir (str) – Directory containing the templates and configuration

  • config_file (str, optional) – Name of the configuration file within the template directory, defaults to 'config.yaml'

copy_one_file(model: StateMachine, output_file: str, src_file: str) → None[source]

Copy a single file to the output directory.

Parameters:

  • model (StateMachine) – The state machine model (unused in this method)

  • output_file (str) – Path to the output file

  • src_file (str) – Path to the source file

Raises:

IOError – If there is an error copying the file

render(model: StateMachine, output_dir: str, clear_previous_directory: bool = False) → None[source]

Render the state machine model to the output directory.

This method processes all template files and copies all other files from the template directory to the output directory according to the configured mappings.

Parameters:

  • model (StateMachine) – The state machine model to render

  • output_dir (str) – Directory where the rendered files will be placed

  • clear_previous_directory (bool, optional) – Whether to clear the output directory before rendering, defaults to False

Raises:

IOError – If there is an error accessing or writing to the output directory

Example:

>>> renderer = StateMachineCodeRenderer('./templates')
>>> renderer.render(my_state_machine, './output', clear_previous_directory=True)
render_one_file(model: StateMachine, output_file: str, template_file: str) → None[source]

Render a single template file.

Parameters:

  • model (StateMachine) – The state machine model to render

  • output_file (str) – Path to the output file

  • template_file (str) – Path to the template file

Raises:

  • jinja2.exceptions.TemplateError – If there is an error in the template

  • IOError – If there is an error reading or writing files