mirror of
https://github.com/michaelcmartin/Ophis.git
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91 lines
2.5 KiB
Python
91 lines
2.5 KiB
Python
"""Symbol tables and environments for Ophis.
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Implements the symbol lookup, through nested environments -
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any non-temporary variable is stored at the top level."""
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# Copyright 2002-2014 Michael C. Martin and additional contributors.
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# You may use, modify, and distribute this file under the MIT
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# license: See README for details.
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import Ophis.Errors as Err
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class Environment(object):
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"""Environment class.
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Controls the various scopes and global abstract execution variables."""
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def __init__(self):
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self.dicts = [{}]
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self.stack = [0]
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self.pc = 0
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self.segmentdict = {}
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self.segment = "*text-default*"
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self.scopecount = 0
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def __contains__(self, item):
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if item[0] == '_':
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for dict in [self.dicts[i] for i in self.stack]:
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if item in dict:
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return True
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return False
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return item in self.dicts[0]
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def __getitem__(self, item):
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if item[0] == '_':
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for dict in [self.dicts[i] for i in self.stack]:
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if item in dict:
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return dict[item]
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else:
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if item in self.dicts[0]:
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return self.dicts[0][item]
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Err.log("Unknown label '%s'" % item)
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return 0
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def __setitem__(self, item, value):
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if item[0] == '_':
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self.dicts[self.stack[0]][item] = value
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else:
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self.dicts[0][item] = value
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def __str__(self):
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return str(self.dicts)
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def getPC(self):
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return self.pc
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def setPC(self, value):
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self.pc = value
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def incPC(self, amount):
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self.pc += amount
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def getsegment(self):
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return self.segment
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def setsegment(self, segment):
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self.segmentdict[self.segment] = self.pc
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self.segment = segment
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self.pc = self.segmentdict.get(segment, 0)
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def reset(self):
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"Clears out program counter, segment, and scoping information"
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self.pc = 0
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self.segmentdict = {}
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self.segment = "*text-default*"
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self.scopecount = 0
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if len(self.stack) > 1:
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Err.log("Unmatched .scope")
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self.stack = [0]
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def newscope(self):
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"Enters a new scope for temporary labels."
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self.scopecount += 1
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self.stack.insert(0, self.scopecount)
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if len(self.dicts) <= self.scopecount:
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self.dicts.append({})
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def endscope(self):
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"Leaves a scope."
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if len(self.stack) == 1:
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Err.log("Unmatched .scend")
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self.stack.pop(0)
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