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996
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1 // ListVar.h
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2
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3 #ifndef LIST_VAR_H_RAIL_1
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4 #define LIST_VAR_H_RAIL_1
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5
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6 #include "Var.h"
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7 #include "NilVar.h"
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8
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9 struct ConsCell
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10 {
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11 ConsCell(Binding newCar = NIL, Binding newCdr = NIL)
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12 : car(newCar)
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13 , cdr(newCdr)
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14 {
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15 }
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16 Binding car;
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17 Binding cdr;
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18 };
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19
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20 class ListVar : public Var
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21 {
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22 public:
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23 ListVar()
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24 : car(NIL)
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25 , cdr(NIL) {}
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26 ListVar(Binding newCar, Binding newCdr)
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27 : car(newCar), cdr(newCdr) {}
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28 virtual ~ListVar() {}
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29
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30 virtual StringVar * getString(void)
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31 {
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32 return NULL;
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33 }
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34
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35 virtual ListVar * getList(void)
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36 {
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37 return this;
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38 }
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39
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40 virtual NilVar * getNil(void)
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41 {
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42 return NULL;
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43 }
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44
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45 virtual Closure * getClosure(void)
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46 {
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47 return NULL;
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48 }
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49
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50 virtual std::string toString(void) const
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51 {
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52 return "(cons " + car->toString() + " " + cdr->toString() + ")";
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53 }
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54
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55 ConsCell getCell(void) const
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56 {
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57 return ConsCell(car, cdr);
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58 }
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59
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60 Binding getCar(void) const
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61 {
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62 return car;
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63 }
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64
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65 Binding getCdr(void) const
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66 {
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67 return cdr;
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68 }
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69 private:
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70 ListVar(ListVar const &) {}
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71 ListVar & operator=(ListVar const &) { return *this; }
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72 private:
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73 Binding car;
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74 Binding cdr;
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75 };
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76
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77 #endif
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