plain-parser

Python parser for ***plain specification files.

Reads a .plain module and its import / requires chain, resolves Liquid templates, validates concepts and linked resources, and returns the marshalled specification tree plus the ordered list of functionalities (FRIDs).

Install

pip install plain-parser

Command line

plain-parser check <file.plain> [--template-dir DIR] [--config-name NAME]
plain-parser parse <file.plain> [--template-dir DIR] [--config-name NAME]

Both commands parse the module and its requires chain, check that every linked resource is an existing file (not a directory), and walk the module's functionalities. They stop at the first error.

check

Validates the module. In addition to the steps above it reads every linked file and rejects binary files and files holding a large base64 blob.

$ plain-parser check my_spec.plain
my_spec.plain: OK

Exit 0 when the module is valid. On an error, Error: … is written to stderr and the exit code is 1.

parse

Prints the parse result as one UTF-8 JSON document on stdout. Linked files are located but not read.

$ plain-parser parse my_spec.plain
{
  "format_version": 1,
  "modules": [{"module": "...", "tree": {...}}, ...],
  "resources": {...}
}

• format_version: 1.
• modules: every module in the requires chain, in build order: deepest ancestor first, the module itself last. Each entry has the module name and its specification tree, in the shape described under Python below.
• resources: every linked-resource target in the chain, as written in the spec, mapped to the path it resolves to, relative to the entry module's directory, with / as separator: notes.md when found next to the module, ../tpl/notes.md when found in a template directory. The directory part is lexical (symlinks not resolved) and the target is appended as written (.. kept), so joining the value onto the entry module's directory names the file the parser matched. When no relative path exists (another drive on Windows) the value is the absolute path, still with /. Two spellings of one file (notes.md, ./notes.md) are two keys.

Exit 0 on success. On a parser error the JSON is {"format_version": 1, "type": "<error class>", "message": "…"} and the exit code is 1.

Options and exit codes

Modules and {% include %} templates are looked up in the .plain file's directory, then in --template-dir. When --template-dir is not given, it is read from the template-dir key of config.yaml (or the file named by --config-name), found next to the .plain file or in the working directory. Finding it in both is a usage error. The config file is read even when --template-dir is given, so a malformed one fails the run either way. Other config keys are ignored.

Python

from plain_parser import plain_file_parser

module_name, plain_source_tree, required_modules = plain_file_parser("my_spec.plain", ["."])

plain_source_tree is a dict keyed by section (definitions, implementation reqs, test reqs, functional specs), each a list of {"markdown": ..., "linked_resources": [...]} entries. plain_parser.plain_spec has helpers for walking functionalities (get_frids, get_specifications_for_frid, collect_linked_resources).

Development

uv venv --python 3.11 && source .venv/bin/activate
uv pip install -e ".[dev]"
pytest
black . --check && isort . --check-only && flake8 . && mypy src

License

MIT, see LICENSE.