1 | [[tags: egg]] |
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2 | |
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3 | == iset |
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4 | |
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5 | [[toc:]] |
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6 | |
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7 | === Description |
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8 | |
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9 | Integer sets. |
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10 | |
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11 | === Author |
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12 | |
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13 | [[Alex Shinn]] |
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14 | |
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15 | === Requirements |
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16 | |
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17 | None |
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18 | |
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19 | === Documentation |
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20 | |
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21 | ==== Bit-vectors |
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22 | |
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23 | Bit-vectors provide an abstract interface to bitwise operations |
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24 | typically done with integers. They may in fact be implemented as |
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25 | integers on implementations with bignums, or they may be implemented |
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26 | by other means such as vectors which may be more efficient. These |
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27 | vectors are meant to be used as flags and sets, not integer values, |
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28 | and thus are operations are ones-complement (there are no negative |
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29 | bit-vectors). |
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30 | |
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31 | ===== Creating bit-vectors |
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32 | |
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33 | <procedure>(make-bit-vector size)</procedure> |
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34 | |
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35 | A 'zero' bit-vector, with a hint that we wish to use {{SIZE}} bits. |
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36 | |
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37 | <procedure>(make-bit-vector size #t)</procedure> |
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38 | |
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39 | Same as above but initialize the all bit elements to {{#t}} (= the integer |
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40 | 2^SIZE-1) |
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41 | |
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42 | <procedure>(integer->bit-vector n)</procedure> |
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43 | |
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44 | Create a bit-vector with bits initialized to the corresponds bits in |
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45 | fixnum N |
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46 | |
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47 | <procedure>(bit-vector-copy bv)</procedure> |
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48 | |
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49 | Make a copy of the bit-vector BV |
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50 | |
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51 | ===== Bit-vector predicates |
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52 | |
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53 | <procedure>(bit-vector? obj)</procedure> |
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54 | |
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55 | {{#t}} iff OBJ is a valid bit-vector, which is not necessarily a disjoint |
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56 | type |
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57 | |
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58 | <procedure>(bit-vector-empty? bv)</procedure> |
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59 | |
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60 | {{#t}} iff BV has no bits set (the bit-vector equivalent of the ZERO? |
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61 | procedure) |
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62 | |
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63 | <procedure>(bit-vector-full? bv to)</procedure> |
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64 | |
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65 | {{#t}} iff BV has all bits lower than TO set (the low end is 2^i-1) |
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66 | |
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67 | The individual bits in the vector are accessed and set as boolean |
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68 | values: |
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69 | |
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70 | ===== Accessing bit-vector elements |
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71 | |
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72 | <procedure>(bit-vector-ref bv i)</procedure> |
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73 | |
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74 | {{#t}} if the I-th bit in BV is set, else {{#f}} |
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75 | |
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76 | <procedure>(bit-vector-set bv i x)</procedure> |
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77 | |
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78 | Return a new copy of BV with the I-th bit set to boolean x (off iff X |
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79 | is {{#f}}) |
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80 | |
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81 | <procedure>(bit-vector-set! bv i x)</procedure> |
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82 | |
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83 | In-place update version of the above, is allowed but not required to |
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84 | mutate BV |
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85 | |
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86 | ===== Bitwise operations on bit-vectors |
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87 | |
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88 | The following procedures are direct analogues of the corresponding |
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89 | SRFI-33 bitwise operations: |
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90 | |
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91 | <procedure>(bit-vector-length bv)</procedure> |
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92 | |
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93 | {{integer-length}}: the index of the largest bit set in BV |
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94 | |
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95 | <procedure>(bit-vector-count bv)</procedure> |
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96 | |
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97 | {{bit-count}}: the number of set bits in BV |
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98 | |
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99 | <procedure>(bit-vector-shift bv n)</procedure> |
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100 | |
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101 | {{arithmetic-shift}} |
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102 | |
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103 | <procedure>(bit-vector-and bv ...)</procedure> |
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104 | |
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105 | {{bitwise-and}} |
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106 | |
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107 | <procedure>(bit-vector-ior bv ...)</procedure> |
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108 | |
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109 | {{bitwise-ior}} |
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110 | |
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111 | <procedure>(bit-vector-xor bv ...)</procedure> |
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112 | |
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113 | {{bitwise-xor}} |
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114 | |
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115 | <procedure>(bit-vector-eqv bv ...)</procedure> |
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116 | |
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117 | {{bitwise-eqv}} |
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118 | |
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119 | <procedure>(bit-vector-nand bv ...)</procedure> |
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120 | |
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121 | {{bitwise-nand}} |
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122 | |
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123 | <procedure>(bit-vector-nor bv ...)</procedure> |
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124 | |
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125 | {{bitwise-nor}} |
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126 | |
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127 | The following in-place update equivalents are also available, which |
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128 | are allowed, but not required, to mutate their first argument only: |
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129 | |
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130 | <procedure>(bit-vector-shift! bv n)</procedure> |
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131 | <procedure>(bit-vector-and! bv ...)</procedure> |
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132 | <procedure>(bit-vector-ior! bv ...)</procedure> |
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133 | <procedure>(bit-vector-xor! bv ...)</procedure> |
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134 | <procedure>(bit-vector-eqv! bv ...)</procedure> |
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135 | <procedure>(bit-vector-nand! bv ...)</procedure> |
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136 | <procedure>(bit-vector-nor! bv ...)</procedure> |
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137 | |
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138 | ==== Integer sets |
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139 | |
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140 | An integer set is a set of exact integers optimized for minimal space |
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141 | usage and fast membership lookup. General set operations are provided |
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142 | based on the character set operations found in SRFI-14. |
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143 | |
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144 | ===== Creating isets |
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145 | |
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146 | <procedure>(make-iset)</procedure> |
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147 | |
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148 | An empty integer set. |
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149 | |
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150 | <procedure>(make-iset n)</procedure> |
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151 | |
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152 | A set of the single integer N. |
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153 | |
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154 | <procedure>(make-iset n m)</procedure> |
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155 | |
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156 | A set of the range of all integers from N-M inclusive. |
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157 | |
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158 | ===== SRFI-14 analogues |
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159 | |
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160 | The following procedures are provided as direct analogs of the SRFI-14 |
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161 | procedures, accepting and returning isets and integers in place of |
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162 | char-sets and characters: |
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163 | |
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164 | <procedure>(iset-copy is)</procedure> |
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165 | |
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166 | A new copy of IS |
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167 | |
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168 | <procedure>(iset n ...)</procedure> |
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169 | |
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170 | An iset containing the elements N... |
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171 | |
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172 | <procedure>(list->iset ls [base-is])</procedure> |
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173 | |
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174 | An iset containing all the integers in list LS, union BASE-IS if |
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175 | provided |
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176 | |
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177 | <procedure>(list->iset! ls base-is)</procedure> |
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178 | |
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179 | Same as above, allowed but not required to modify base-is |
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180 | |
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181 | <procedure>(iset-size is)</procedure> |
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182 | |
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183 | Return the # of elements in IS |
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184 | |
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185 | <procedure>(iset-contains? is n)</procedure> |
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186 | |
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187 | Test N for membership in IS |
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188 | |
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189 | <procedure>(iset->list is)</procedure> |
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190 | |
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191 | Returns a list of all integers in IS |
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192 | |
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193 | <procedure>(iset-any pred is)</procedure> |
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194 | |
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195 | Apply PRED to every element of IS, returning the first element it |
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196 | finds (order unspecified) |
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197 | |
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198 | <procedure>(iset-every pred is)</procedure> |
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199 | |
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200 | Returns {{#t}} if every element of IS satisfies the predicate PRED (order |
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201 | unspecified) |
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202 | |
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203 | <procedure>(iset? obj)</procedure> |
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204 | |
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205 | {{#t}} iff obj is an integer set. |
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206 | |
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207 | <procedure>(iset= is ...)</procedure> |
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208 | |
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209 | {{#t}} iff all arguments are equivalent integer sets. |
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210 | |
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211 | <procedure>(iset<= is ...)</procedure> |
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212 | |
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213 | {{#t}} iff the arguments are monotonically increasing sets. |
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214 | |
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215 | <procedure>(iset>= is ...)</procedure> |
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216 | |
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217 | {{#t}} iff the arguments are monotonically decreasing sets. |
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218 | |
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219 | <procedure>(iset-fold kons knil is)</procedure> |
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220 | |
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221 | {{char-set-fold}} |
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222 | |
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223 | <procedure>(iset-unfold f p g [base-is])</procedure> |
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224 | |
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225 | {{char-set-unfold}} |
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226 | |
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227 | <procedure>(iset-unfold! f p g base-is)</procedure> |
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228 | |
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229 | {{char-set-unfold!}} |
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230 | |
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231 | <procedure>(iset-for-each proc is)</procedure> |
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232 | |
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233 | {{char-set-for-each}} |
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234 | |
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235 | <procedure>(iset-map proc is)</procedure> |
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236 | |
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237 | {{char-set-map}} |
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238 | |
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239 | <procedure>(iset-filter pred is [bas-is])</procedure> |
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240 | |
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241 | {{char-set-filter}} |
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242 | |
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243 | <procedure>(iset-filter! pred is base-is)</procedure> |
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244 | |
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245 | {{char-set-filter!}} |
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246 | |
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247 | <procedure>(iset-cursor iset)</procedure> |
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248 | <procedure>(iset-ref iset cursor)</procedure> |
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249 | <procedure>(iset-cursor-next iset cursor)</procedure> |
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250 | <procedure>(end-of-iset? iset)</procedure> |
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251 | |
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252 | Cursor-based traversal of isets. |
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253 | |
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254 | <procedure>(iset-adjoin is n ...)</procedure> |
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255 | |
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256 | {{char-set-adjoin}} |
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257 | |
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258 | <procedure>(iset-delete is n ...)</procedure> |
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259 | |
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260 | {{char-set-delete}} |
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261 | |
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262 | <procedure>(iset-adjoin! is n ...)</procedure> |
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263 | |
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264 | {{char-set-adjoin!}} |
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265 | |
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266 | <procedure>(iset-delete! is n ...)</procedure> |
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267 | |
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268 | {{char-set-delete!}} |
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269 | |
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270 | <procedure>(iset-union is1 ...)</procedure> |
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271 | |
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272 | {{char-set-union}} |
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273 | |
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274 | <procedure>(iset-intersection is1 ...)</procedure> |
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275 | |
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276 | {{char-set-intersection}} |
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277 | |
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278 | <procedure>(iset-difference is1 is2 ...)</procedure> |
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279 | |
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280 | {{char-set-difference}} |
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281 | |
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282 | <procedure>(iset-xor is1 ...)</procedure> |
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283 | |
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284 | {{char-set-xor}} |
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285 | |
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286 | <procedure>(iset-diff+intersection is1 is2 ...)</procedure> |
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287 | |
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288 | {{char-set-diff+intersection}} |
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289 | |
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290 | <procedure>(iset-union! is1 ...)</procedure> |
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291 | |
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292 | {{char-set-union!}} |
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293 | |
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294 | <procedure>(iset-intersection! is1 ...)</procedure> |
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295 | |
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296 | {{char-set-intersection!}} |
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297 | |
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298 | <procedure>(iset-difference! is1 is2 ...)</procedure> |
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299 | |
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300 | {{char-set-difference!}} |
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301 | |
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302 | <procedure>(iset-xor! is1 ...)</procedure> |
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303 | |
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304 | {{char-set-xor!}} |
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305 | |
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306 | <procedure>(iset-diff+intersection! is1 is2 ...)</procedure> |
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307 | |
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308 | {{char-set-diff+intersection!}} |
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309 | |
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310 | === Changelog |
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311 | |
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312 | * 1.5 Port to hygienic chicken, fix overflow bug in bit-vector-full? [Peter Bex] |
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313 | * 1.4 Workaround in {{bit-vector-copy}} for zero-length vectors. |
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314 | * 1.3 Fixed {{bit-vector-copy}} export but no define [by Kon Lovett] |
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315 | * 1.2 Added {{iset-optimize}} and {{iset-balance}}, fixed some bugs |
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316 | * 1.1 Added cursors |
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317 | * 1.0 Initial release |
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318 | |
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319 | === License |
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320 | |
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321 | Copyright (c) 2004-2006, Alex Shinn |
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322 | All rights reserved. |
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323 | |
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324 | Redistribution and use in source and binary forms, with or without |
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325 | modification, are permitted provided that the following conditions |
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326 | are met: |
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327 | 1. Redistributions of source code must retain the above copyright |
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328 | notice, this list of conditions and the following disclaimer. |
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329 | 2. Redistributions in binary form must reproduce the above copyright |
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330 | notice, this list of conditions and the following disclaimer in the |
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331 | documentation and/or other materials provided with the distribution. |
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332 | 3. The name of the author may not be used to endorse or promote products |
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333 | derived from this software without specific prior written permission. |
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334 | |
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335 | THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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336 | IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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337 | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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338 | IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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339 | INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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340 | NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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341 | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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342 | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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343 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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344 | THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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