https://github.com/zbraniecki/pyast

Basic set of classes for building abstract syntax trees
https://github.com/zbraniecki/pyast

Last synced: 12 months ago
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Basic set of classes for building abstract syntax trees

• Host: GitHub
• URL: https://github.com/zbraniecki/pyast
• Owner: zbraniecki
• License: bsd-3-clause
• Created: 2011-06-02T15:21:58.000Z (about 15 years ago)
• Default Branch: master
• Last Pushed: 2018-03-07T07:01:32.000Z (over 8 years ago)
• Last Synced: 2025-03-25T08:23:03.942Z (about 1 year ago)
• Language: Python
• Homepage:
• Size: 39.1 KB
• Stars: 10
• Watchers: 2
• Forks: 3
• Open Issues: 1
• Metadata Files:
  • Readme: README
  • License: LICENSE

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README

          
PyAST is a library that allows for creating AST structures using declarative programming form.

example:

== jsast.py ==

import pyast as ast

class Node(ast.Node):

    pass

class Statement(Node):

    pass

class Expression(Pattern):

    pass

class Operator(Node):

    token = ast.field(("+","=","-","==","!=",">",">"))

class Identifier(Expression):

    name = ast.field((str, unicode))

class Literal(Expression):

    value = ast.field((str, bool, int, NoneType))

class Program(ast.Node):

    body = ast.seq(Statement, null=True)

class ExpressionStatement(Statement):

    expression = ast.field(Expression)

class AssignmentExpression(Expression):

    operator = ast.field(Operator)

    left = ast.field(Expression)

    right = ast.field(Expression)

== main.py ==

from jsast import *

prog = Program()

prog.body.append(

    ExpressionStatement(

        AssignmentExpression(

            Operator("="),

            Identifier("x"),

            Literal(2)

        )))

# result: x=2;

=========

pyast.DEBUG variable defines if pyast operates in DEBUG mode in which the 

strong typing is enforced at cost of performance, or optimized mode when all

the checks are inactive.