1 | //----------------------------------------------------------------------------- |
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2 | /// @file rf_term.hh |
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3 | /// |
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4 | /// Refal+ term interface |
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5 | // |
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6 | // $Source$ |
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7 | // $Revision: 723 $ |
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8 | // $Date: 2003-05-05 12:04:11 +0000 (Mon, 05 May 2003) $ |
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9 | //----------------------------------------------------------------------------- |
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10 | |
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11 | #ifndef __rf_term_hh__ |
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12 | #define __rf_term_hh__ |
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13 | |
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14 | #include "rf_memory_chunk.hh" |
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15 | #include "rf_common.hh" |
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16 | #include "rf_types.hh" |
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17 | #include "rf_object.hh" |
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18 | #include "pxx_string.hh" |
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19 | |
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20 | /// |
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21 | /// A namespace for Refal runtime |
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22 | namespace rfrt |
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23 | { |
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24 | |
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25 | using namespace rftype ; |
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26 | |
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27 | // |
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28 | // In previous runtime version we keeped the order of memory block in each |
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29 | // reference term. This was needed to compute a pointer of a memory block. |
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30 | // Now an allocator is able to get this pointer for us, so we don't need all |
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31 | // stuff related to this. However, we still keep old code, because in a future |
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32 | // we may return to the old scheme if it can lead to faster program execution. |
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33 | #if !defined(RF_STORE_CHUNK_ORDER_IN_TERM) |
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34 | |
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35 | typedef enum { |
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36 | term_sym, |
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37 | term_ref, |
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38 | term_obj, |
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39 | term_class_num |
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40 | } term_class_t ; |
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41 | |
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42 | /// |
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43 | /// "Flat" bit. This bit, if set for reference term, means that referenced |
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44 | /// expression is "flat", i.e. it contains only short symbols, so we should |
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45 | /// accurately handle this when destroying the expression. This bit was |
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46 | /// introduced because in a case of a "flat" expression we don't need to walk |
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47 | /// through and dereference childs. |
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48 | /// This bit is kept as invariant during all expression operations. |
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49 | #define FLAT_BIT (uintptr_t(0x04)) |
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50 | /// |
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51 | /// Pointer mask. Used to obtain a clear pointer from term data. |
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52 | #define PTR_MASK ~(uintptr_t((sizeof(uintptr_t) << 1) - 1)) |
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53 | /// |
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54 | /// Type mask. Used to distinguish between reference term and other terms. |
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55 | /// This is the maximum number of internal "short" types (i.e. types that can |
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56 | /// be placed in place in term data. |
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57 | #define TYPE_MASK (uintptr_t(0xFFFF0)) |
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58 | #define CLASS_MASK (uintptr_t(0x03)) |
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59 | #define TYPE_SHIFT 4 |
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60 | |
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61 | #else |
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62 | #if UINTPTR_MAX == UINT32_MAX |
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63 | #define ORDER_SHIFT 3 |
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64 | #define REF_BIT (uintptr_t(0x04)) |
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65 | #define PTR_MASK (~(uintptr_t(0x07))) |
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66 | #define ORDER1_MASK (uintptr_t(0x03)) |
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67 | #define ORDER2_MASK (uintptr_t(0x07)) |
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68 | #elif UINTPTR_MAX == UINT64_MAX |
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69 | #define ORDER_SHIFT 4 |
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70 | #define REF_BIT (uintptr_t(0x08)) |
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71 | #define PTR_MASK (~(uintptr_t(0x0F))) |
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72 | #define ORDER1_MASK (uintptr_t(0x03)) |
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73 | #define ORDER2_MASK (uintptr_t(0x0F)) |
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74 | #else |
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75 | #error "Unsupported pointer size" |
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76 | #endif |
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77 | //#define COMPOUND_BIT (uintptr_t(0x8000)) |
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78 | //#define CHAR_SHIFT ((sizeof(uintptr_t) - sizeof (uint16_t)) * 8) |
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79 | #define ORDER1(x) ((uintptr_t)((x) >> ORDER_SHIFT)) |
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80 | #define ORDER2(x) ((uintptr_t)((x) & ORDER2_MASK)) |
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81 | #define ORDER(x,y) (((x) << ORDER_SHIFT) | (y)) |
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82 | |
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83 | #endif // RF_STORE_CHUNK_ORDER_IN_TERM |
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84 | |
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85 | //----------------------------------------------------------------------------- |
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86 | /// Refal term. This is one of two basic runtime classes, which describes |
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87 | /// Refal expression elements. |
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88 | /// |
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89 | /// FIXME: To follow all invariants it is necessary to define copy ctor and |
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90 | /// assignment operator, which should increment memory block reference counter |
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91 | /// in a case of reference term. Destructor should decrement this reference |
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92 | /// counter appropriately. This is not done for optimization purposes. |
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93 | //----------------------------------------------------------------------------- |
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94 | class Term |
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95 | { |
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96 | /// |
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97 | /// We can access all term fields from expression class and some methods |
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98 | friend class Expr ; |
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99 | friend inline Expr operator + (Term const&, Expr const&) ; |
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100 | friend inline Expr operator + (Term const&, Term const&) ; |
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101 | friend inline bool flat_eq ( |
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102 | Expr const& _e1, uintptr_t _pos1, |
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103 | Expr const& _e2, uintptr_t _pos2, uintptr_t _len ); |
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104 | |
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105 | protected: |
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106 | /// |
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107 | /// The first term field containing symbol type or (in a case of reference |
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108 | /// term) pointer to the first term of referenced expresion |
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109 | uintptr_t data1 ; |
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110 | /// |
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111 | /// The second term field containing actual data (for short type), pointer |
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112 | /// to object (for object extensions) or pointer to the right margin of |
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113 | /// referenced expression |
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114 | |
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115 | union { |
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116 | uintptr_t uint_data2 ; |
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117 | intptr_t int_data2 ; |
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118 | void* ptr_data2 ; |
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119 | }; |
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120 | |
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121 | /// |
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122 | /// Constructor for empty term with given class and type |
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123 | inline Term (term_class_t _class, unsigned _type) ; |
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124 | /// |
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125 | /// Create expression with specified length |
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126 | static inline Expr create_expr (size_t _len, int _align = 0) ; |
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127 | private: |
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128 | /// |
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129 | /// Constructor for a character term. All constructors are private because |
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130 | /// they should be called only from expression implementation. |
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131 | /// FIXME: Originally it was planned that all strings in Refal will be |
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132 | /// unicode-based (there will be no difference in expression size, because |
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133 | /// a term can contain either usual character or wide character). However it |
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134 | /// was decided later to have both character types, so probably instead of |
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135 | /// this we should have Term (char _c) and Term (wchar_t _c). |
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136 | inline Term (uint16_t _c) ; |
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137 | /// |
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138 | /// Constructor for a reference term. It is is needed for Expr::operator() |
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139 | /// implementation. |
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140 | /// FIXME: The definition of this method is in rf_expr.hh now. It should be |
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141 | /// moved into rf_term.ih, when expression interface and implementation will |
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142 | /// be separated. |
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143 | inline Term (Expr const& _expr) ; |
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144 | inline Term (Object* _obj) ; |
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145 | |
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146 | inline Term (Term const& _t) ; |
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147 | inline Term& operator = (Term const& _t) ; |
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148 | |
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149 | typedef void (Term::*ctor_func_t)(Term const& _t) ; |
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150 | typedef void (Term::*dtor_func_t)() ; |
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151 | typedef bool (Term::*eq_func_t)(Term const& _t) const ; |
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152 | typedef pxx::WString (Term::*to_string_func_t)() const ; |
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153 | typedef size_t (Term::*get_char_len_func_t)() const ; |
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154 | typedef Term* (Term::*to_chars_func_t)(Term* _p) const ; |
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155 | |
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156 | static ctor_func_t ctor_funcs[term_class_num] ; |
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157 | static dtor_func_t dtor_funcs[term_class_num] ; |
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158 | static eq_func_t eq_funcs[term_class_num] ; |
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159 | static to_string_func_t to_string_funcs[term_class_num] ; |
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160 | |
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161 | void ctor_sym (Term const& _t) ; |
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162 | void ctor_ref (Term const& _t) ; |
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163 | void ctor_obj (Term const& _t) ; |
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164 | void dtor_sym () ; |
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165 | void dtor_ref () ; |
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166 | void dtor_obj () ; |
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167 | bool eq_sym (Term const& _t) const ; |
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168 | bool eq_ref (Term const& _t) const ; |
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169 | bool eq_obj (Term const& _t) const ; |
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170 | pxx::WString to_string_sym () const ; |
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171 | pxx::WString to_string_ref () const ; |
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172 | pxx::WString to_string_obj () const ; |
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173 | |
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174 | public: |
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175 | /// |
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176 | /// Destructor. |
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177 | inline ~Term () ; |
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178 | /// |
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179 | /// Check whether two terms are equal |
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180 | inline bool operator == (Term const& _t) const ; |
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181 | /// |
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182 | /// Check whether two terms are not equal |
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183 | inline bool operator != (Term const& _t) const ; |
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184 | /// |
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185 | /// Check whether two term sequences are equal |
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186 | static inline bool eq ( |
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187 | Term const* _f1, Term const* _l1, Term const* _f2, Term const* _l2 |
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188 | ) ; |
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189 | /// |
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190 | /// Check whether a term is a reference term |
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191 | inline bool is_ref () const ; |
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192 | /// |
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193 | /// Check whether a term is a symbol |
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194 | inline bool is_sym () const ; |
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195 | /// |
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196 | /// Check whether a term is a border symbol |
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197 | inline bool is_border () const ; |
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198 | /// |
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199 | /// Get a pointer to the first term of referenced expression for a reference |
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200 | /// term. Note that this method doesn't check whether a term is a reference |
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201 | /// term. |
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202 | inline Term* get_first () const ; |
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203 | /// |
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204 | /// Get a pointer to the right margin of referenced expression for |
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205 | /// a reference term. Note that this method doesn't checkwhether a term is |
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206 | /// a reference term. |
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207 | inline Term* get_last () const ; |
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208 | /// |
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209 | /// Get a type of "short" symbol. |
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210 | inline unsigned get_type () const ; |
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211 | /// |
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212 | /// Set a type of "short" symbol. |
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213 | inline void set_type (unsigned _type) ; |
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214 | inline term_class_t get_class () const ; |
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215 | inline void set_class (term_class_t _class) ; |
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216 | inline Object& get_object () ; |
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217 | /// |
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218 | /// Get a pointer to memory block containing referenced expression. Note |
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219 | /// that this method doesn't check whether a term is a reference term. |
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220 | inline MemoryChunk* get_mem_chunk() const ; |
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221 | |
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222 | inline operator pxx::WString () const ; |
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223 | |
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224 | #if defined(RF_STORE_CHUNK_ORDER_IN_TERM) |
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225 | inline unsigned get_order () const |
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226 | { |
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227 | return ORDER(data1 & ORDER1_MASK, data2 & ORDER2_MASK); |
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228 | } |
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229 | #endif |
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230 | |
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231 | }; |
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232 | |
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233 | } |
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234 | |
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235 | #endif // __rf_term_hh__ |
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