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