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148
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1 from . import astnodes
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150
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2 from .scope import Scope, topScope
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148
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3
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4 class Semantics:
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5 """ This class constructs the AST from parser input """
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6 def __init__(self, diag):
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7 self.diag = diag
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150
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8 def addSymbol(self, s):
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9 if self.curScope.hasSymbol(s.name):
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10 msg = 'Redefinition of {0}'.format(s.name)
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152
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11 self.diag.error(msg, s.loc)
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150
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12 else:
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13 self.curScope.addSymbol(s)
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148
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14 def handlePackage(self, name, loc):
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15 self.mod = astnodes.Package(name)
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16 self.mod.loc = loc
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150
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17 self.mod.scope = self.curScope = Scope(topScope)
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18 def actOnVarDef(self, name, loc, t, ival):
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19 s = astnodes.Variable(name, t)
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20 s.loc = loc
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21 self.addSymbol(s)
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22 def actOnFuncDef1(self, name, loc):
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23 self.curFunc = astnodes.Function(name)
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24 self.curFunc.loc = loc
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25 self.addSymbol(self.curFunc)
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26 self.curScope = self.curFunc.scope = Scope(self.curScope)
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27 def actOnParameter(self, name, loc, t):
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28 p = astnodes.Variable(name, t)
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29 p.loc = loc
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30 p.parameter = True
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31 self.addSymbol(p)
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32 return p
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33 def actOnFuncDef2(self, parameters, returntype, body):
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34 self.curFunc.body = body
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35 self.curFunc.typ = astnodes.FunctionType(parameters, returntype)
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36 self.curFunc = None
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37 self.curScope = self.curScope.parent
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38 def actOnType(self, tok):
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39 # Try to lookup type, in case of failure return void
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40 pass
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41 def actOnDesignator(self, tname, loc):
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42 d = astnodes.Designator(tname)
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43 d.scope = self.curScope
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44 d.loc = loc
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45 return d
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149
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46 def actOnBinop(self, lhs, op, rhs, loc):
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47 bo = astnodes.Binop(lhs, op, rhs)
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48 bo.loc = loc
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49 return bo
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50 def actOnNumber(self, num, loc):
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51 n = astnodes.Constant(num)
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52 n.loc = loc
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53 return n
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150
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54 def actOnVariableUse(self, d):
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55 return astnodes.VariableUse(d)
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148
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56
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