91 lines
2.4 KiB
Python
91 lines
2.4 KiB
Python
#!/usr/bin/env python
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# encoding: utf-8
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from .generic import Stack,isOperator
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__all__ = ['txt', 'tex', 'p2i']
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class Render(object):
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""" Create functions which know how to render postfix tokens lists """
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def __init__(self, render):
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"""Initiate the render
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:param render: function which take an operator and return a function to render the operator with his operands
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"""
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self.render = render
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def __call__(self, postfix_tokens):
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"""Make the object acting like a function
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:param postfix_tokens: the list of postfix tokens to be render
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:returns: the render string
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"""
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operandeStack = Stack()
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for token in postfix_tokens:
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if isOperator(token):
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if token.arity == 1:
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op1 = operandeStack.pop()
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operandeStack.push(self.render(token)(op1))
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elif token.arity == 2:
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op1 = operandeStack.pop()
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op2 = operandeStack.pop()
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# Switch op1 and op2 to respect order
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operandeStack.push(self.render(token)(op2, op1))
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else:
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operandeStack.push(self.render(token)())
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if len(operandeStack) > 1:
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raise ValueError("This postfix_tokens is not a valid expression")
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else:
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return operandeStack.pop()
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def txt_render(token):
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def render(*args):
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try:
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return getattr(token, '__txt__')(*args)
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except AttributeError:
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return str(token)
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return render
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txt = Render(txt_render)
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def tex_render(token):
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def render(*args):
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try:
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return getattr(token, '__tex__')(*args)
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except AttributeError:
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return str(token)
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return render
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tex = Render(tex_render)
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def p2i_render(token):
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def render(*args):
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try:
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return getattr(token, '__p2i__')(*args)
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except AttributeError:
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return token
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return render
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p2i = Render(p2i_render)
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if __name__ == '__main__':
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from .operator import op
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exp = [ 2, 3, op.add, 4, op.mul]
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print(exp)
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print("txt(exp) :" + str(txt(exp)))
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print("tex(exp) :" + str(tex(exp)))
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print("p2i(exp) :" + str(p2i(exp)))
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# -----------------------------
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# Reglages pour 'vim'
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# vim:set autoindent expandtab tabstop=4 shiftwidth=4:
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# cursor: 16 del
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