https://github.com/samvv/sweetener

A base library for building tools that work with syntax
https://github.com/samvv/sweetener

ast library parse-trees syntax

Last synced: about 1 month ago
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A base library for building tools that work with syntax

• Host: GitHub
• URL: https://github.com/samvv/sweetener
• Owner: samvv
• License: mit
• Created: 2020-04-14T17:59:28.000Z (over 4 years ago)
• Default Branch: main
• Last Pushed: 2024-03-02T16:29:45.000Z (10 months ago)
• Last Synced: 2024-07-06T07:01:53.672Z (6 months ago)
• Topics: ast, library, parse-trees, syntax
• Language: Python
• Homepage: https://pypi.org/project/sweetener
• Size: 138 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.txt

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README

        
Sweetener

=========

[![Python package](https://github.com/samvv/sweetener/actions/workflows/python-package.yml/badge.svg)](https://github.com/samvv/sweetener/actions/workflows/python-package.yml) [![Coverage Status](https://coveralls.io/repos/github/samvv/sweetener/badge.svg?branch=main)](https://coveralls.io/github/samvv/sweetener?branch=main) [![PyPI version](https://badge.fury.io/py/sweetener.svg)](https://pypi.org/project/sweetener)

Sweetener is a Python library for quickly prototyping compilers and

interpreters. Extra care has been taken to make the algorithms as flexible as

possible to fit as many use cases. If you're still missing something, do not

hesitate to file an [issue][1]! In particular, this library contains the

following goodies:

 - **A typed record type** that allows you to build PODs very quickly.

 - **Base classes for an AST/CST**, including reflection procedures.

 - **A means for writing diagnostics** that can print part of your source code

   alongside your error messages.

 - **Generic procedures** like `clone`, `equal` and `lte` that work on most

   types in the standard library and you can specialize for your own types.

[1]: https://github.com/samvv/sweetener/issues

## Examples

Here's an example of using the `Record` type to define a record that holds two

fields and visualizes tham using GraphViz:

```py

from sweetener import Record, equal, visualize

class MySimpleRecord(Record):

    field_1: int

    field_2: str

r1 = MySimpleRecord('foo', 42)

r2 = MySimpleRecod(field_1='foo', field_2=42)

assert(equal(r1, r2))

visualize(r1)

```

Running this program will open a new window with the following content:



```py

from sweetener import BaseNode, visualize

class CalcNode(BaseNode):

    pass

class Expr(CalcNode):

    pass

class Add(Expr):

    left: Expr

    right: Expr

class Sub(Expr):

    left: Expr

    right: Expr

class Var(Expr):

    name: str

class Lit(Expr):

    value: int

def eval(node: Expr, vars = {}) -> int:

    if isinstance(node, Add):

        return eval(node.left, vars) + eval(node.right, vars)

    if isinstance(node, Sub):

        return eval(node.left, vars) - eval(node.right, vars)

    if isinstance(node, Lit):

        return node.value

    if isinstance(node, Var):

        return vars[node.name]

    raise RuntimeError('Could not evaluate a node: unrecognised node type')

prog = Sub(

    Add(

        Lit(1),

        Lit(2)

    ),

    Var('x')

)

visualize(prog, format='png')

assert(eval(prog, { 'x': 3 }) == 0)

```

Running this example will open a new window with the following content:



## License

Sweetener is generously licensed under the MIT license, in the hope that it

inspires people to build new and cool software.