Ruby-style blocks in Python

ruby_blocks_in_python.py

class EvalBlock(object):

    def __init__(self, code_string):
        self.code_object = compile(code_string, '<code>', mode='eval')

    def __call__(self, *args, **kwargs):
        return eval(self.code_object)


class ExecBlock(object):

    def __init__(self, code_string):
        self.code_object = compile(code_string, '<code>', mode='exec')

    def __call__(self, *args, **kwargs):
        return eval(self.code_object)


# Because we can't add methods to int in Python
class NumberObject(int):

    def times(self, block):
        for i in range(0, int(self)):
            block(i)

    def upto(self, upper_num, block):
        for i in range(int(self), int(upper_num)):
            block(i)


# Because we can't add methods to list in Python
class ListObject(list):

    def collect(self, block):
        ret = []

        for item in self:
            ret.append(block(item))

        return ret


NumberObject(5).times(ExecBlock("""
print "%d - %s" % (args[0], args[0] * '*')
"""))

NumberObject(1).upto(5, ExecBlock("""
print "%d - %s" % (args[0], args[0] * '*')
"""))

ret = ListObject([1, 2, 3]).collect(EvalBlock("args[0] * 2"))

print "result of collect => %r" % ret