Midas is a type system to Maintain Integrity of Data with Annotated Structures. In Greek mythology, Midas was a Phrygian king who was blessed with the gift of turning everything he touched into gold.

Midas aims at providing Python developers with a simple annotation system to enable compile-time integrity and data type checks, as well as generating runtime assertions.

This framework is being developed as part of a Bachelor's Thesis by Louis Heredero at HEI Sion.

Requirements

Python 3.11+
uv

Installation

Clone the repository

git clone https://git.kb28.ch/HEL/midas.git

Go in the project directory
```
cd midas
```
Install the CLI as a user-wide tool
```
uv tool install .
```
You can now run the midas command from anywhere
```
midas --help
```

Commands

Compiling

Note

In the current state of the project, the compile command doesn't generate any runnable code, it only runs the parsers and type checker on the provided files

midas compile -t types.midas source.py

With the compile command, you can process a source Python file, with any number of custom type definition files (-t FILE option), and the type checker will verify the coherence of your program and generate the runnable code with valid syntax and runtime assertions.

The optional -l FILE option lets you produce a highlighted version of the source code showing diagnostics from the type checker (see Highlighting)

Highlighting

midas utils highlight source.py
# or
midas utils highlight types.midas

The highlight command takes in a source file (Python or Midas), runs the appropriate parser and outputs an HTML file containing the source code with added highlighting. This highlighting takes the form of hoverable annotations showing some of the parsed structures (e.g. a function definition, an assignment, a generic type, etc.)

The optional -o FILE option can be used to specify an output path. By default, the file is printed in stdout (equivalent to -o -).

Dumping the AST

midas utils dump-ast source.py
# or
midas utils dump-ast types.midas

For debugging purposes, you can output the AST parsed from a Python or Midas file. For Python files, the -p flags lets you toggle the custom AST parsing. Without -p, the raw AST is returned, as produced by the builtin ast module. This flag has no effect on Midas files.

The optional -o FILE option can be used to specify an output path. By default, the file is printed in stdout (equivalent to -o -).

Tests

Several snapshot tests are available to assert the good behaviour of the parsers and type checker. They can be run as follows:

uv run -m tests.midas run -a
uv run -m tests.python run -a
uv run -m tests.checker run -a

Available subcommands:

Run all tests: run -a
Run specific tests: run tests/cases/test1.py tests/cases/test2.py ...
Update all tests: update -a
Update specific tests: update tests/cases/test1.py tests/cases/test2.py ...