mirror of https://github.com/m-labs/artiq
59 lines
2.0 KiB
Python
59 lines
2.0 KiB
Python
"""
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:class:`ConstnessValidator` checks that no attribute marked
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as constant is ever set.
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"""
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from pythonparser import algorithm, diagnostic
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from .. import types, builtins
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class ConstnessValidator(algorithm.Visitor):
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def __init__(self, engine):
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self.engine = engine
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self.in_assign = False
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def visit_Assign(self, node):
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self.visit(node.value)
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self.in_assign = True
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self.visit(node.targets)
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self.in_assign = False
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def visit_AugAssign(self, node):
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self.visit(node.value)
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self.in_assign = True
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self.visit(node.target)
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self.in_assign = False
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def visit_SubscriptT(self, node):
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old_in_assign, self.in_assign = self.in_assign, False
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self.visit(node.value)
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self.visit(node.slice)
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self.in_assign = old_in_assign
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if self.in_assign and builtins.is_bytes(node.value.type):
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diag = diagnostic.Diagnostic("error",
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"type {typ} is not mutable",
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{"typ": "bytes"},
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node.loc)
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self.engine.process(diag)
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def visit_AttributeT(self, node):
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old_in_assign, self.in_assign = self.in_assign, False
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self.visit(node.value)
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self.in_assign = old_in_assign
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if self.in_assign:
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typ = node.value.type.find()
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if types.is_instance(typ) and node.attr in typ.constant_attributes:
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diag = diagnostic.Diagnostic("error",
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"cannot assign to constant attribute '{attr}' of class '{class}'",
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{"attr": node.attr, "class": typ.name},
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node.loc)
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self.engine.process(diag)
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return
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if builtins.is_array(typ):
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diag = diagnostic.Diagnostic("error",
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"array attributes cannot be assigned to",
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{}, node.loc)
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self.engine.process(diag)
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return
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