1 | [[tags: egg]] |
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2 | [[toc:]] |
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3 | |
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4 | == tuples |
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5 | |
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6 | Tuples are a datatype which has much in common with vectors. Namely they store a finite number of items with random access and make them available via (tuple-ref tup n). But contrary to vectors, the items can only by accessed but not assigned to. If you want to change a particular item, you must package it into a box or a single, which is a special tuple storing exactly one item, which can be changed via single-set! without changing the identity of the single object itself. |
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7 | |
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8 | singles are the only tuples, which can assign to their content. Other special tuples are empty, couple and triple. Note, that couples can be used instead of pairs to implement immutable lists. |
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9 | |
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10 | == Documentation |
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11 | |
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12 | In this implementation skiplists are implemented in the Design by |
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13 | Contract style, i.e. using the contracts module. A corollary of this is, |
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14 | that the documentation is included in one of the two modules in form of |
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15 | a procedure with the module's name. Apart from this documentation |
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16 | procedure the two modules, %tuples and tuples, have the same |
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17 | interface. The first module contains the raw implementations of the |
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18 | procedures, the second imports the first with prefix % and wraps those |
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19 | prefixed routines with contracts. |
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20 | |
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21 | ==== tuples |
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22 | |
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23 | <procedure>(tuples [sym])</procedure> |
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24 | |
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25 | returns all available routines of the module when called without an |
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26 | argument, but when called with one of these routines as a symbol, |
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27 | returns its contract and documentation string. |
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28 | |
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29 | Another way to get the complete documentation is to use print-doclist from the contracts module. Issuing |
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30 | |
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31 | <enscript highlight=scheme> |
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32 | (import tuples (only contracts print-doclist)) |
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33 | (with-output-to-file "tuples.docu" (lambda () (print-doclist))) |
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34 | </enscript> |
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35 | |
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36 | you'll get a file tuples.docu which is the basis for the following |
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37 | documentation. |
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38 | |
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39 | ==== triple-right |
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40 | |
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41 | <procedure>(triple-right tup)</procedure> |
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42 | |
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43 | returns the right item of a triple |
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44 | |
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45 | ==== triple-middle |
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46 | |
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47 | <procedure>(triple-middle tup)</procedure> |
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48 | |
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49 | returns the middle item of a triple |
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50 | |
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51 | ==== triple-left |
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52 | |
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53 | <procedure>(triple-left tup)</procedure> |
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54 | |
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55 | returns the left item of a triple |
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56 | |
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57 | ==== triple |
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58 | |
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59 | <procedure>(triple x y z)</procedure> |
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60 | |
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61 | constructor for a tuple storing two items |
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62 | |
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63 | ==== triple? |
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64 | |
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65 | <procedure>(triple? x)</procedure> |
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66 | |
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67 | tests for a tuple storing two items |
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68 | |
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69 | ==== couple-right |
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70 | |
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71 | <procedure>(couple-right tup)</procedure> |
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72 | |
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73 | returns the right item of a couple |
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74 | |
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75 | ==== couple-left |
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76 | |
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77 | <procedure>(couple-left tup)</procedure> |
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78 | |
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79 | returns the left item of a couple |
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80 | |
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81 | ==== couple |
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82 | |
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83 | <procedure>(couple x y)</procedure> |
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84 | |
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85 | constructor for a tuple storing two items |
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86 | |
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87 | ==== couple? |
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88 | |
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89 | <procedure>(couple? x)</procedure> |
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90 | |
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91 | tests for a tuple storing two items |
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92 | |
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93 | ==== single-set! |
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94 | |
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95 | <procedure>(single-set! sg arg)</procedure> |
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96 | |
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97 | <enscript highlight=scheme> |
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98 | (domain (%single? sg) (true? arg)) |
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99 | (effect (state (%tuple-state sg) arg)) |
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100 | </enscript> |
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101 | |
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102 | replaces state of sg with arg |
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103 | |
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104 | ==== single-ref |
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105 | |
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106 | <procedure>(single-ref sg)</procedure> |
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107 | |
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108 | <enscript highlight=scheme> |
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109 | (domain (%single? sg)) |
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110 | </enscript> |
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111 | |
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112 | returns the state of the single object sg |
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113 | |
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114 | ==== single |
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115 | |
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116 | <procedure>(single xpr)</procedure> |
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117 | |
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118 | <enscript highlight=scheme> |
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119 | (domain (true? xpr)) |
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120 | (range (%single? result)) |
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121 | </enscript> |
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122 | |
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123 | package xpr into a box so that it can be modified |
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124 | |
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125 | ==== single? |
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126 | |
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127 | <procedure>(single? xpr)</procedure> |
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128 | |
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129 | check, if xpr evaluates to a single |
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130 | |
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131 | ==== empty |
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132 | |
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133 | <procedure>(empty)</procedure> |
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134 | |
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135 | constructor for an empty tuple |
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136 | |
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137 | ==== empty? |
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138 | |
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139 | <procedure>(empty? x)</procedure> |
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140 | |
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141 | tests for an empty tuple |
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142 | |
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143 | ==== tuple-for-each |
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144 | |
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145 | <procedure>(tuple-for-each proc tup)</procedure> |
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146 | |
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147 | <enscript highlight=scheme> |
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148 | (domain (%tuple? tup) (procedure? proc) a one parameter procedure) |
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149 | </enscript> |
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150 | |
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151 | apply a one parameter procedure to each item of tup |
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152 | |
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153 | ==== tuple->list |
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154 | |
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155 | <procedure>(tuple->list tup)</procedure> |
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156 | |
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157 | <enscript highlight=scheme> |
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158 | (domain (%tuple? tup)) |
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159 | (range (list? result)) |
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160 | </enscript> |
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161 | |
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162 | transforms a tuple into a list |
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163 | |
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164 | ==== tuple-find |
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165 | |
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166 | <procedure>(tuple-find tup item compare?)</procedure> |
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167 | |
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168 | <enscript highlight=scheme> |
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169 | (domain (%tuple? tup) (procedure? compare?) a two parameter predicate) |
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170 | (range (or (not result) (and (cardinal? result) (< result (%tuple-length tup))))) |
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171 | </enscript> |
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172 | |
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173 | checks by comparing with compare? if item is contained in tup |
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174 | |
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175 | ==== tuple-right |
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176 | |
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177 | <procedure>(tuple-right tup)</procedure> |
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178 | |
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179 | <enscript highlight=scheme> |
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180 | (domain (%tuple? tup) (>= (%tuple-length tup) 2)) |
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181 | </enscript> |
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182 | |
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183 | returns the rightmost item of tup |
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184 | |
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185 | ==== tuple-left |
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186 | |
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187 | <procedure>(tuple-left tup)</procedure> |
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188 | |
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189 | <enscript highlight=scheme> |
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190 | (domain (%tuple? tup) (positive? (%tuple-length tup))) |
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191 | </enscript> |
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192 | |
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193 | returns the leftmost item of tup |
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194 | |
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195 | ==== tuple-ref |
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196 | |
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197 | <procedure>(tuple-ref tup n)</procedure> |
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198 | |
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199 | <enscript highlight=scheme> |
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200 | (domain (%tuple? tup) (cardinal? n) (< n (%tuple-length tup))) |
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201 | </enscript> |
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202 | |
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203 | returns the n'th item of tup, counting from zero |
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204 | |
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205 | ==== tuple-length |
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206 | |
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207 | <procedure>(tuple-length tup)</procedure> |
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208 | |
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209 | <enscript highlight=scheme> |
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210 | (domain (%tuple? tup)) |
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211 | (range (cardinal? result)) |
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212 | </enscript> |
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213 | |
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214 | returns the number of tuple items |
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215 | |
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216 | ==== tuple-copy |
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217 | |
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218 | <procedure>(tuple-copy tup . interval)</procedure> |
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219 | |
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220 | <enscript highlight=scheme> |
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221 | (domain (%tuple? tup) |
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222 | (<= (length interval) 2) |
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223 | ((list-of? cardinal?) interval) |
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224 | (apply <= (append interval (list (%tuple-length tup))))) |
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225 | (range (%tuple? result)) |
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226 | </enscript> |
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227 | |
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228 | constructing a subtuple with tup data from interval |
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229 | |
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230 | ==== tuple-append |
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231 | |
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232 | <procedure>(tuple-append . tups)</procedure> |
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233 | |
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234 | <enscript highlight=scheme> |
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235 | (domain ((list-of? tuple?) tups)) |
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236 | (range (%tuple? result)) |
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237 | </enscript> |
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238 | |
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239 | constructs a new tuple by concatenating several others |
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240 | |
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241 | ==== tuple-map |
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242 | |
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243 | <procedure>(tuple-map fn tup)</procedure> |
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244 | |
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245 | <enscript highlight=scheme> |
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246 | (domain (%tuple? tup) (procedure? fn) a one parameter function) |
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247 | (range (%tuple? result)) |
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248 | </enscript> |
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249 | |
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250 | constructs a new tuple by mapping each item of tup with function fn |
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251 | |
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252 | ==== list->tuple |
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253 | |
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254 | <procedure>(list->tuple lst)</procedure> |
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255 | |
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256 | <enscript highlight=scheme> |
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257 | (domain (list? lst)) |
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258 | (range (%tuple? result)) |
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259 | </enscript> |
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260 | |
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261 | transforms a list into a tuple |
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262 | |
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263 | ==== tuple |
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264 | |
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265 | <procedure>(tuple . args)</procedure> |
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266 | |
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267 | <enscript highlight=scheme> |
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268 | (domain (true? args)) |
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269 | (range (%tuple? result)) |
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270 | </enscript> |
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271 | |
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272 | tuple constructor |
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273 | |
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274 | ==== tuple-of? |
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275 | |
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276 | <procedure>(tuple-of? ok?)</procedure> |
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277 | |
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278 | <enscript highlight=scheme> |
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279 | (domain (procedure? ok?) ok? is a one parameter predicate) |
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280 | (range (procedure? result) result is a one parameter predicate) |
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281 | </enscript> |
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282 | |
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283 | checks, if each tuple item satisfies predicate ok? |
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284 | |
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285 | ==== tuple? |
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286 | |
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287 | <procedure>(tuple? xpr)</procedure> |
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288 | |
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289 | checks if xpr evaluates to a tuple |
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290 | |
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291 | |
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292 | == Requirements |
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293 | |
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294 | [[contracts]] |
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295 | |
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296 | == Last update |
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297 | |
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298 | Aug 02, 2012 |
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299 | |
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300 | == Author |
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301 | |
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302 | [[/users/juergen-lorenz|Juergen Lorenz]] |
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303 | |
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304 | == License |
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305 | |
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306 | Copyright (c) 2012, Juergen Lorenz |
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307 | All rights reserved. |
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308 | |
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309 | Redistribution and use in source and binary forms, with or without |
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310 | modification, are permitted provided that the following conditions are |
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311 | met: |
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312 | |
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313 | Redistributions of source code must retain the above copyright |
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314 | notice, this list of conditions and the following disclaimer. |
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315 | |
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316 | Redistributions in binary form must reproduce the above copyright |
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317 | notice, this list of conditions and the following disclaimer in the |
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318 | documentation and/or other materials provided with the distribution. |
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319 | Neither the name of the author nor the names of its contributors may be |
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320 | used to endorse or promote products derived from this software without |
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321 | specific prior written permission. |
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322 | |
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323 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
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324 | IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
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325 | TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A |
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326 | PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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327 | HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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328 | SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED |
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329 | TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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330 | PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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331 | LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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332 | NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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333 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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334 | |
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335 | == Version History |
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336 | |
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337 | ; 0.8 : code split into two modules |
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338 | ; 0.7 : single-state and single-state! renamed to single-ref and single-set! |
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339 | ; 0.6 : contracts rewritten |
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340 | ; 0.5 : code maintenance |
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341 | ; 0.4 : added copyright notice |
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342 | ; 0.3 : updated for using contracts 1.0 |
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343 | ; 0.2 : added tuple-copy, tuple-left, tuple-right |
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344 | ; 0.1 : initial import |
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