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148
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1 from . import astnodes
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2
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3 class Scope:
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4 """ A scope contains all symbols in a scope """
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5 def __init__(self, parent=None):
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6 self.symbols = {}
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7 self.parent = parent
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149
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8 def __iter__(self):
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9 return iter(self.symbols.values())
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148
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10 def getType(self, name):
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11 t = self.getSymbol(name)
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12 print(t)
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13 assert isinstance(t, astnodes.Type)
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14 return t
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15 def getSymbol(self, name):
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16 if name in self.symbols:
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17 return self.symbols[name]
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18 # Look for symbol:
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19 if self.parent:
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20 return self.parent.getSymbol(name)
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21 raise CompilerException("Symbol {0} not found".format(name), name.loc)
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22 def hasSymbol(self, name):
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23 if name in self.symbols:
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24 return True
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25 if self.parent:
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26 return self.parent.hasSymbol(name)
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27 return False
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28
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29 def addSymbol(self, sym):
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30 self.symbols[sym.name] = sym
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31
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32 def createBuiltins(scope):
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33 scope.addSymbol(astnodes.BaseType('int'))
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34
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35 class Semantics:
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36 """ This class constructs the AST from parser input """
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37 def __init__(self, diag):
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38 self.diag = diag
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39 def handlePackage(self, name, loc):
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40 self.mod = astnodes.Package(name)
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41 self.mod.loc = loc
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42 self.mod.scope = self.curScope = Scope()
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43 createBuiltins(self.curScope)
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149
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44 def actOnBinop(self, lhs, op, rhs, loc):
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45 bo = astnodes.Binop(lhs, op, rhs)
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46 bo.loc = loc
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47 return bo
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48 def actOnNumber(self, num, loc):
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49 n = astnodes.Constant(num)
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50 n.loc = loc
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51 return n
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52 def actOnVarDef(self, name, loc, t, ival):
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53 s = astnodes.Variable(name, t)
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54 s.loc = loc
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148
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55 self.curScope.addSymbol(s)
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149
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56 def actOnFuncDef1(self, name, loc):
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57 self.curFunc = astnodes.Procedure(name)
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58 self.curFunc.loc = loc
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59 self.curScope.addSymbol(self.curFunc)
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60 self.curScope = self.curFunc.scope = Scope(self.curScope)
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61 def actOnFuncDef2(self, parameters, returntype, body):
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62 self.curFunc.body = body
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63 self.curFunc.typ = astnodes.FunctionType(parameters, returntype)
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64 self.curFunc = None
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65 self.curScope = self.curScope.parent
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148
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66 def actOnType(self, tok):
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67 # Try to lookup type, in case of failure return void
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68 pass
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69
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