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163
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1 from .astnodes import *
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2 from .scope import *
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3 from .visitor import Visitor
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4
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5 def equalTypes(a, b):
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6 """ Compare types a and b for equality. Not equal until proven otherwise. """
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7 if type(a) is type(b):
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8 if type(a) is BaseType:
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9 return a.name == b.name
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10 return False
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150
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11
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12 class TypeChecker:
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13 def __init__(self, diag):
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14 self.diag = diag
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163
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15 self.visitor = Visitor(self.precheck, self.check2)
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150
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16 def checkPackage(self, pkg):
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163
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17 self.visitor.visit(pkg)
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18 def precheck(self, sym):
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19 pass
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20 def check2(self, sym):
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21 if type(sym) is Function:
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22 pass
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165
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23 elif type(sym) in [IfStatement, WhileStatement]:
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163
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24 if not equalTypes(sym.condition.typ, boolType):
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25 self.diag.error('Condition must be a boolean expression', sym.condition.loc)
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150
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26 elif type(sym) is Assignment:
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164
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27 if not equalTypes(sym.lval.typ, sym.rval.typ):
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28 self.diag.error('Cannot assign {0} to {1}'.format(sym.rval.typ, sym.lval.typ), sym.loc)
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150
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29 elif type(sym) is ReturnStatement:
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163
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30 pass
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31 elif type(sym) is ProcedureCall:
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32 # Check arguments:
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33
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34 # determine return type:
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35 sym.typ = sym.proc.typ.returntype
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36 elif type(sym) is VariableUse:
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37 if sym.target:
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38 sym.typ = sym.target.typ
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39 else:
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165
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40 sym.typ = intType
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163
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41 elif type(sym) is Literal:
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42 if type(sym.val) is int:
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43 sym.typ = intType
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44 elif type(sym.val) is float:
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45 sym.typ = doubleType
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46 else:
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47 self.diag.error('Unknown literal type', sym.loc)
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150
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48 elif type(sym) is Binop:
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163
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49 if sym.op in ['+', '-', '*', '/']:
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50 if equalTypes(sym.a.typ, sym.b.typ):
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51 sym.typ = sym.a.typ
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52 else:
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165
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53 # assume void here? TODO: throw exception!
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54 sym.typ = intType
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163
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55 self.diag.error('Types unequal', sym.loc)
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56 elif sym.op in ['>', '<']:
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165
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57 sym.typ = boolType
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58 if not equalTypes(sym.a.typ, sym.b.typ):
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163
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59 self.diag.error('Types unequal', sym.loc)
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60 else:
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61 sym.typ = voidType
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62 print('unknown binop', sym.op)
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165
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63 elif type(sym) is Variable:
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64 # check initial value type:
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65 # TODO
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66 pass
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67 elif type(sym) in [EmptyStatement, CompoundStatement, Package]:
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68 pass
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163
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69 else:
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70 print('Unknown type check', sym)
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150
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71
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