| 1 | """Definition of the OMBinding object""" |
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| 2 | from objects import OMObjectBase, OMSymbol |
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| 3 | from cd import OMCD |
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| 4 | #from omexceptions import UnsupportedOperationError |
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| 5 | from itertools import izip |
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| 6 | from copy import copy |
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| 7 | cdFns1 = OMCD("fns1") |
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| 8 | lambdasym = OMSymbol("lambda", cdFns1) |
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| 9 | |
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| 10 | def islambda(sym): |
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| 11 | "return True, iff sym is the lambda binder" |
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| 12 | return lambdasym == sym |
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| 13 | |
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| 14 | class OMBinding(OMObjectBase): |
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| 15 | """hopefully fixed possible problems: reevaluation writes new scope, |
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| 16 | if it isn't |
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| 17 | meant so, references do not work correctly because of scopes |
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| 18 | solve this by first evaluation to bounded OMBinding""" |
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| 19 | def __init__(self, binder, variables, block): |
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| 20 | super(OMBinding, self).__init__() |
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| 21 | self.block = block |
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| 22 | self.binder = binder |
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| 23 | self.variables = variables |
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| 24 | self.bounded = False |
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| 25 | def evaluate(self, context): |
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| 26 | "evaluate the OMbinding in context" |
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| 27 | assert islambda(self.binder) |
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| 28 | if not self.bounded: |
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| 29 | mycopy = copy(self) |
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| 30 | mycopy.scope = context.scopeFromCurrentScope() |
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| 31 | mycopy.bounded = True |
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| 32 | return mycopy |
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| 33 | else: |
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| 34 | return self |
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| 35 | def bind(self, args): |
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| 36 | "bind arguments to values" |
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| 37 | #print args, self.variables |
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| 38 | assert len(args) == len(self.variables) |
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| 39 | varBindings = dict(izip([i.name for i in self.variables], args)) |
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| 40 | self.scope.push(varBindings) |
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| 41 | def unbind(self): |
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| 42 | "unbind the arguments" |
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| 43 | self.scope.pop() |
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| 44 | |
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| 45 | def calcErg(self, context): |
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| 46 | "do the actual computation" |
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| 47 | return context.evaluateInScope(self.block, self.scope) |
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| 48 | def __call__(self, context, *args): |
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| 49 | self.bind(args) |
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| 50 | erg = self.calcErg(context) |
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| 51 | self.unbind() |
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| 52 | #print "__call__ erg is", erg |
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| 53 | return erg |
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| 54 | |
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| 55 | XMLtag = "OMBIND" |
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| 56 | def getChildren(self): |
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| 57 | "get children for (XML) representation" |
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| 58 | return [self.binder]+self.variables+[self.block] |
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| 59 | |
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