Pyjaco IST design

gistfile1.txt

import ast

def transform(node, transformations):
    """
        Match node a node in transformations.
    """

    match = transformations.get(type(node))

    if match:
        # we found a match, convert it to ist.
        return match.from_ast(node)
    else:
        print "did not find type:", type(node)

# some random ist nodes. 
class Module:

    def __init__(self):
        print "Creating Module"
        self.stmts = []

    @staticmethod
    def from_ast(node):
        mod = Module()

        for stmt in node.body:
            mod.add_stmt(transform(stmt, to_ist))

        return mod

    def add_stmt(self, stmt):
        self.stmts.append(stmt)

    def __str__(self):
        return '\n'.join(str(stmt) for stmt in self.stmts)


class Expr:

    def __init__(self, value):
        print "Creating Expr with value", value
        self.value = value

    @staticmethod
    def from_ast(node):
        return Expr(transform(node.value, to_ist))

    def __str__(self):
        return str(self.value)


class Str:

    def __init__(self, s):
        print "Creating Str({})".format(s)
        self.s = s

    @staticmethod
    def from_ast(node):
        return Str(node.s)

    def __str__(self):
        return self.s

#The ast -> ist transformation table

to_ist = {
    ast.Module : Module,
    ast.Expr   : Expr,
    ast.Str    : Str
}

source = "'bla'"

print transform(ast.parse(source), to_ist)