Formalize translator design and workflow

[tdv42]

e.g. using flow diagram

[bugdea1er]

Requirements:

• The jar executable should take the path of the python input file as a command line argument, and optionally take the path of the output file.
• If the Python input file has valid Python 3.9 syntax, translate it to eolang and write the result to the output file provided, or place the result near the input file if no output files were provided.
• If the input python does not have valid Python 3.9 syntax, inform the user.
• The repository should provide a set of tests which can be transpiled to the executable eolang code.
• The repository should provide tools for transpiling some big python project, indicate that no exceptions were thrown from the transpiler and the resulting eolang files are syntactically correct.

[bugdea1er]

Workflow:

• The main function parses the command line arguments and (if an existing input file was provided) gets the input content
• The parser module uses the ANTLR parser to build an abstract syntax tree and then maps its tree to a custom design tree for easier use.
• The simple pass module applies several py2py passes to eliminate some constructions which are not supported in eolang.
• The resulting simplified AST is then translated to the eolang code.

[dours]

added description of my python-to-python passes https://github.com/polystat/py2eo/wiki/Workflow-description

[bugdea1er]

Requirements and workflow desing description moved here:
https://github.com/polystat/py2eo/wiki/Requirements-and-workflow-design