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1 from .nodes import *
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2 from .errors import Error
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3
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4 class SymbolTable:
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5 """
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6 Symbol table for a current scope.
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7 It has functions:
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8 - hasname for checking for a name in current scope or above
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9 - addSymbol to add an object
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10 """
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11 def __init__(self, parent=None):
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12 self.parent = parent
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13 self.syms = {}
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14
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15 def __repr__(self):
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16 return 'Symboltable with {0} symbols\n'.format(len(self.syms))
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17
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18 def printTable(self, indent=0):
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19 for name in self.syms:
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20 print(self.syms[name])
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21
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22 def getAllLocal(self, cls):
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23 """ Get all local objects of a specific type """
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24 r = []
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25 for key in self.syms.keys():
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26 sym = self.syms[key]
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27 if issubclass(type(sym), cls):
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28 r.append(sym)
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29 return r
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30
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31 def getLocal(self, cls, name):
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32 if name in self.syms.keys():
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33 sym = self.syms[name]
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34 if isinstance(sym, cls):
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35 return sym
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36 else:
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37 Error('Wrong type found')
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38 else:
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39 Error('Symbol not found')
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40
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41 # Retrieving of specific classes of items:
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42 def get(self, cls, name):
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43 if self.hasSymbol(name):
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44 sym = self.getSymbol(name)
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45 if issubclass(type(sym), cls):
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46 return sym
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47 raise SymbolException('type {0} undefined'.format(typename))
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48
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49 def has(self, cls, name):
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50 if self.hasSymbol(name):
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51 sym = self.getSymbol(name)
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52 if issubclass(type(sym), cls):
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53 return True
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54 return False
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55
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56 # Adding and retrieving of symbols in general:
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57 def addSymbol(self, sym):
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58 if sym.name in self.syms.keys():
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59 raise Exception('Symbol "{0}" redefined'.format(sym.name))
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60 else:
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61 self.syms[sym.name] = sym
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62
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63 def getSymbol(self, name):
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64 if name in self.syms.keys():
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65 return self.syms[name]
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66 else:
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67 if self.parent:
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68 return self.parent.getSymbol(name)
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69 else:
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70 Error('Symbol "{0}" undeclared!'.format(name))
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71
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72 def hasSymbol(self, name):
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73 if name in self.syms.keys():
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74 return True
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75 else:
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76 if self.parent:
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77 return self.parent.hasSymbol(name)
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78 else:
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79 return False
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80
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