Support Match

[odashi]

It would be great if we support the match statement added in Python 3.10, but the entire syntax is somewhat complex.

https://docs.python.org/3/library/ast.html#pattern-matching

[erica-w-fu]

Could I get assigned to this issue? I would love to contribute to this repo!

[odashi]

@erica-w-fu Hi, feel free to work on this!
Since the overall syntax around Match is very huge, I'd like to decompose it to small developments (pull requests) mainly for ease of reviewing.

[erica-w-fu]

Could I get some clarification on what is expected? Are we trying to convert match statements to latex? What does support mean exactly?

[odashi]

Basically implementing some codegen rules in function_codegen.py is all you need.

As for "small development", you can start to implement only a specific portion in the whole syntax (e.g., I think supporting only MatchValue is the easiest one).
For all other cases, we should raise LatexifyNotSupportedError, which marks "not supported, but we'll support it in the future". For example:

class FunctionCodegen(NodeVisitor):
    ...
    def visit_Match(self, node: ast.Match) -> str:
        if isinstance(node.pattern, ast.MatchValue):
            return ...something...
        
        raise exceptions.LatexifyNotSupportedError("Unsupported match syntax.")

[odashi]

I think the whole match case can't be supported in latexify.function because there are capture clauses that there aren't any corresponding syntax in math. It would be better to support only syntaxes with:

• Constants
• sequence/dict with only constants

[odashi]

The resulting LaTeX could be expressed semilarly to that of the if clause:

match x:
    case 0:
        return 1
    case _:
        return math.sin(x)/x

$$\left\{ \begin{array}{ll} 1, & \mathrm{if} \ x = 0 \\ \frac{\sin(x)}{x}, & \mathrm{otherwise} \end{array} \right.$$

[erica-w-fu]

That makes a lot of sense! Thanks for the clarification

[erica-w-fu]

How can we build the project for development? Are there any detailed docs that explain how to build and test latexify/our implementation?

[odashi]

@erica-w-fu I will add some documentation. For now you can install the development version as follows:

cd /path/to/latexify_py
python -m venv venv  # Create a virtual environment
python -m pip install -e '.[dev]' # Install latexify as the editable mode with some libraries

jupyter notebook is also installed by the command above.

[erica-w-fu]

Thanks! I was able to run all of the tests. Are there any build tools and commands that you use to test within jupyter notebook?