mirror of https://github.com/python/cpython
113 lines
3.5 KiB
Python
113 lines
3.5 KiB
Python
"""Variables, arguments and argument transfer modes etc."""
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# Values to represent argument transfer modes
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InMode = 1 # input-only argument
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OutMode = 2 # output-only argument
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InOutMode = 3 # input-output argument
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ModeMask = 3 # bits to keep for mode
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# Special cases for mode/flags argument
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# XXX This is still a mess!
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SelfMode = 4+InMode # this is 'self' -- don't declare it
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ReturnMode = 8+OutMode # this is the function return value
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ErrorMode = 16+OutMode # this is an error status -- turn it into an exception
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RefMode = 32
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ConstMode = 64
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class Variable:
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"""A Variable holds a type, a name, a transfer mode and flags.
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Most of its methods call the correponding type method with the
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variable name.
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"""
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def __init__(self, type, name = None, flags = InMode):
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"""Call with a type, a name and flags.
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If name is None, it muse be set later.
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flags defaults to InMode.
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"""
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self.type = type
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self.name = name
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self.flags = flags
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self.mode = flags & ModeMask
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def declare(self):
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"""Declare the variable if necessary.
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If it is "self", it is not declared.
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"""
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if self.flags == ReturnMode+RefMode:
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self.type.declare(self.name, reference=True)
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elif self.flags != SelfMode:
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self.type.declare(self.name)
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def getArgDeclarations(self, fullmodes=False):
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refmode = (self.flags & RefMode)
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constmode = False
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outmode = False
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if fullmodes:
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constmode = (self.flags & ConstMode)
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outmode = (self.flags & OutMode)
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return self.type.getArgDeclarations(self.name,
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reference=refmode, constmode=constmode, outmode=outmode)
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def getAuxDeclarations(self):
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return self.type.getAuxDeclarations(self.name)
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def getargsFormat(self):
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"""Call the type's getargsFormatmethod."""
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return self.type.getargsFormat()
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def getargsArgs(self):
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"""Call the type's getargsArgsmethod."""
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return self.type.getargsArgs(self.name)
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def getargsCheck(self):
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return self.type.getargsCheck(self.name)
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def getargsPreCheck(self):
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return self.type.getargsPreCheck(self.name)
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def passArgument(self):
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"""Return the string required to pass the variable as argument.
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For "in" arguments, return the variable name.
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For "out" and "in out" arguments,
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return its name prefixed with "&".
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"""
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if self.mode == InMode:
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return self.type.passInput(self.name)
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if self.mode & RefMode:
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return self.type.passReference(self.name)
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if self.mode in (OutMode, InOutMode):
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return self.type.passOutput(self.name)
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# XXX Shouldn't get here
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return "/*mode?*/" + self.type.passInput(self.name)
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def errorCheck(self):
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"""Check for an error if necessary.
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This only generates code if the variable's mode is ErrorMode.
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"""
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if self.flags == ErrorMode:
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self.type.errorCheck(self.name)
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def mkvalueFormat (self):
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"""Call the type's mkvalueFormat method."""
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return self.type.mkvalueFormat()
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def mkvalueArgs(self):
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"""Call the type's mkvalueArgs method."""
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return self.type.mkvalueArgs(self.name)
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def mkvaluePreCheck(self):
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return self.type.mkvaluePreCheck(self.name)
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def cleanup(self):
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"""Call the type's cleanup method."""
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return self.type.cleanup(self.name)
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