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1 {{{#!python
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2 class Expr(object):
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3 def __init__(self, a, op=None, b=None):
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4 self.a, self.op, self.b = a, op, b
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5 def __repr__(self):
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6 if self.op:
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7 if self.b:
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8 return '(%r %s %r)' % (self.a, self.op, self.b)
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9 else:
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10 return '(%s%r)' % (self.op, self.a)
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11 return self.a
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12 def __add__(self, other):
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13 return Expr(self, '+', other)
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14 def __sub__(self, other):
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15 return Expr(self, '-', other)
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16 def __mul__(self, other):
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17 return Expr(self, '*', other)
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18 def __div__(self, other):
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19 return Expr(self, '/', other)
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20 def __neg__(self, other):
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21 return Expr(self, '-')
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22 def __pos__(self, other):
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23 return Expr(self, '+')
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24 }}} |
