55 lines
1.4 KiB
Python
55 lines
1.4 KiB
Python
"""
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Spreadsheet example adapted from Raymond Hettinger's `recipe`__
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__ http://code.activestate.com/recipes/355045-spreadsheet/
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Demonstration::
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>>> from math import sin, pi
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>>> ss = Spreadsheet(sin=sin, pi=pi, abs=abs)
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>>> ss['a1'] = '-5'
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>>> ss['a2'] = 'a1*6'
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>>> ss['a3'] = 'a2*7'
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>>> ss['a3']
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-210
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>>> ss['b1'] = 'sin(pi/4)'
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>>> ss['b1'] # doctest:+ELLIPSIS
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0.707106781186...
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>>> ss.getformula('b1')
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'sin(pi/4)'
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>>> ss['c1'] = 'abs(a2)'
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>>> ss['c1']
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30
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>>> ss['c2'] = 'len(a2)'
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>>> ss['c2']
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Traceback (most recent call last):
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...
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NameError: name 'len' is not defined
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>>> ss['d1'] = '3*'
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Traceback (most recent call last):
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...
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SyntaxError: unexpected EOF while parsing ['d1'] = '3*'
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"""
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class Spreadsheet:
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def __init__(self, **tools):
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self._cells = {}
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self._tools = {'__builtins__' : {}}
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self._tools.update(tools)
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def __setitem__(self, key, formula):
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try:
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compile(formula, '<__setitem__>', 'eval')
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except SyntaxError as exc:
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msg = '{} [{!r}] = {!r}'.format(exc.msg, key, formula)
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raise SyntaxError(msg)
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self._cells[key] = formula
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def getformula(self, key):
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return self._cells[key]
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def __getitem__(self, key):
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return eval(self._cells[key], self._tools, self)
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