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996
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1 // NilVar.h
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2
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3 #ifndef NIL_VAR_H_RAIL_1
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4 #define NIL_VAR_H_RAIL_1
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5
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6 #include "Var.h"
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7
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8 class NilVar : public Var
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9 {
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10 public:
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11 NilVar() {}
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12 virtual ~NilVar() {}
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13
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14 virtual StringVar * getString(void)
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15 {
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16 return NULL;
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17 }
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18
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19 virtual ListVar * getList(void)
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20 {
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21 return NULL;
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22 }
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23
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24 virtual NilVar * getNil(void)
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25 {
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26 return this;
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27 }
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28
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29 virtual Closure * getClosure(void)
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30 {
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31 return NULL;
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32 }
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33
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34 virtual std::string toString(void) const
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35 {
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36 return "<NIL>";
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37 }
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38 private:
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39 NilVar(NilVar const &) {}
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40 NilVar & operator=(NilVar const &) { return *this; }
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41 };
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42
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43 #endif
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