A transpiler that converts Logo code into Python

pablasso, updated 🕥 2022-01-21 19:38:33

Chelodina

PyPI LICENSE Code Style

Chelodina is a transpiler that converts LOGO:

```logo TO triangle :length REPEAT 3 [ FORWARD :length RIGHT 120 ] END

TO flower :length :count REPEAT 150 [ triangle :length RIGHT 360 / :count ] END

TO web REPEAT 6 [ flower 150 18 ] END

web

```

Into Python:

```python import turtle

def triangle(p_length): for _ in range(3): turtle.forward(p_length) turtle.right(120.0)

def flower(p_length, p_count): for _ in range(150): triangle(p_length) turtle.right(360.0 / p_count)

def web(): for _ in range(6): flower(150.0, 18.0)

web() turtle.done() ```

Installation

pip install chelodina

Usage

``` usage: chelodina [-h] --input INPUT [--run]

arguments: -h, --help show this help message and exit --input INPUT Logo source file --run Run the transpiled code ```

There's some ready examples to try if you clone the repository:

chelodina --input examples/example1.logo

You can also trigger the program to run in a GUI:

chelodina --input examples/example1.logo --run

Status

  • Implemented:
    • Motion functions: FORWARD, BACK, LEFT, RIGHT, SETPOS, SETX, SETY, SETHEADING, SETH, HOME
    • Screen functions: DONE, CLEARSCREEN
    • Control structures: REPEAT
    • Function calls and definitions with optional parameters
    • Binary operations

This is still on an early stage, I focused on making some examples work. Functions with similar structure are trivial to implement, but I want to focus on improving the tests first.

For grammar reference look at grammar.bnf.

Known quirks

  • Validations for a valid AST (e.g. to make sure a function parameter exists before trying to use it on a statement) are not user friendly yet. I suggest double-checking your programs elsewhere first.
  • Only tested on Python 3.6+ so far.

Development

Use pipenv to install dependencies:

pipenv install --dev

Running tests

Run tests with:

pipenv run tests

Automatically run tests after detecting changes with:

pipenv run tests-watch

Debug

  • The easy way is to write tests to debug your code. Feel free to use assert False where necessary.
  • If you need to run tests along anything that sends to or needs the standard output (a debugger like pdb or pudb), you'll need to run pytest directly: pytest --capture=no.
  • There's a library to pretty-print your AST in the utils package. Usage example:

```python from chelodina import compiler from chelodina.utils.debug import parseprint

logo_code = """ to myfunction forward 51.0 left 91 end """

parsed_ast = compiler.get_ast(logo_code) parseprint(parsed) ```

And you'll see the resulting AST:

python Module(body=[ Import(names=[ alias(name='turtle', asname=None), ]), FunctionDef(name='myfunction', args=arguments(args=[], vararg=None, kwonlyargs=[], kw_defaults=[], kwarg=None, defaults=[]), body=[ Expr(value=Call(func=Attribute(value=Name(id='turtle', ctx=Load()), attr='forward', ctx=Load()), args=[ Num(n=51.0), ], keywords=[])), Expr(value=Call(func=Attribute(value=Name(id='turtle', ctx=Load()), attr='left', ctx=Load()), args=[ Num(n=91.0), ], keywords=[])), ], decorator_list=[], returns=None), Expr(value=Call(func=Attribute(value=Name(id='turtle', ctx=Load()), attr='done', ctx=Load()), args=[], keywords=[])), ])

Code style

I use black for code formatting, please install the pre-commit hook before doing a PR. This will be enforced with a linter check in the future.

You can run the command manually too:

black .

Not required, but if you install EditorConfig in your editor of choice it will make your life easier.

Issues

Bump ipython from 7.0.0rc1 to 7.16.3

opened on 2022-01-21 19:38:32 by dependabot[bot]

Bumps ipython from 7.0.0rc1 to 7.16.3.

Commits


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Juan Pablo Ortiz
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