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2004-11-17 mantoniotti 1 <html>
22:19:54 ' 2 <head>
' 3 <title>CL Unification: Class ARRAY-TEMPLATE</title>
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' 13 style="font-family:=Verdana,Arial,Helvetica; font-size: 18px; color: #41286f;">
' 14 <strong><i>CL Unification: Class ARRAY-TEMPLATE</title></i></strong>
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' 32
' 33 <div class="content">
' 34 <div class="text" style="padding-top: 10px;">
' 35
' 36 <h1><i>Class</i> <strong>ARRAY-TEMPLATE</strong></h1>
' 37
' 38 <h2>Package:</h2>
' 39
' 40 <p><code>COMMON-LISP.EXTENSIONS.DATA-AND-CONTROL-FLOW.UNIFICATION</code></p>
' 41
' 42
' 43 <h2>Class Precedence List:</h2>
' 44
' 45 <p>
' 46 ARRAY-TEMPLATE, TYPE-TEMPLATE, TEMPLATE, STANDARD-OBJECT, T.
' 47 </p>
' 48
' 49 <h2>Known Subclasses:</h2>
' 50
' 51 <p>
' 52 VECTOR-TEMPLATE.
' 53 </p>
' 54
' 55
' 56 <h2>Slots:</h2>
' 57
' 58 <p>None.</p>
' 59
' 60
' 61 <h2>Description:</h2>
' 62
' 63 <p>The ARRAY-TEMPLATE class denotes those object that are used
' 64 to unify against an ARRAY.</p>
' 65
' 66 <h3>Template Syntax:</h3>
' 67
' 68 <p>
' 69 <pre>
' 70 #T(<b>array</b> <i>&lt;shape-template&gt;</i>)
' 71 </pre>
' 72 </p>
' 73
' 74 <p>
' 75 <pre>
' 76 #T(<i>&lt;<strong>CL</strong> array type specifier&gt;</i> <i>&lt;shape-template&gt;</i>)
' 77 </pre>
' 78 </p>
' 79
' 80 <p>
' 81 <pre>
' 82 #T(<b>array</b> ([* | <i>&lt;<strong>CL</strong> type specifier&gt;</i>] [<i>&lt;dimension sped&gt;</i>]) <i>&lt;shape-template&gt;</i>)
' 83 </pre>
' 84 </p>
' 85
' 86 <p>Where <i>&lt;shape-template&gt;</i> can be:</p>
' 87
' 88 <p>
' 89 <pre>
' 90 <i>&lt;shape-template&gt;</i> ::= <i>&lt;sequence-template&gt;</i>
' 91 | <i>&lt;destructuring template lambda list&gt;</i>
' 92 | (<i>&lt;shape-template&gt;</i>)
' 93 </pre>
' 94 </p>
' 95
' 96
' 97 <p>The ARRAY-TEMPLATE syntax denotes an ARRAY object. An
' 98 ARRAY-TEMPLATE must be unified against an ARRAY object. The elements
' 99 of the array must be unified against the
' 100 <i>&lt;shape-template&gt;</i>. Each row of the array is unified
' 101 recursively against each element of the <i>&lt;shape-template&gt;</i>.
' 102
' 103
' 104
' 105 <h2>Examples:</h2>
' 106
' 107 <p>
' 108 <pre>
' 109 cl-prompt> (setf e (unify #(0 1 42 3 4 5) #T(<b>array</b> (0 1 ?x 3 4 5))))
' 110 #&lt;ENVIRONMENT xxx&gt;
' 111
' 112 cl-prompt> (find-variable-value '?x e)
' 113 42
' 114
' 115 cl-prompt> (setq e (unify #(0 1 42 3 4 5) #T(<b>array</b> (0 1 "FOO" 3 4 5))))
' 116 --> Error: UNIFICATION-FAILURE
' 117
' 118 cl-prompt> (setq e (unify #2A((0 1 42) (3 4 5)) #T(<b>array</b> ((0 1 ?x) (3 4 5)))))
' 119 #&lt;ENVIRONMENT xxx&gt;
' 120
' 121 cl-prompt> (find-variable-value '?x e)
' 122 42
' 123
' 124 cl-prompt> (setq e (unify #2A(("foo" "bar" 42) (3 4 5)) #T(<b>array</b> ((_ _ ?x) (3 4 5)))))
' 125 #&lt;ENVIRONMENT xxx&gt;
' 126
' 127 cl-prompt> (find-variable-value '?x e)
' 128 42
' 129
' 130 cl-prompt> (setq e (unify #2A(("foo" "bar" 42) (3 4 5)) #T(<b>array</b> (#T(vector _ &rest ?x) (3 4 5)))))
' 131 #&lt;ENVIRONMENT xxx&gt;
' 132
' 133 cl-prompt> (find-variable-value '?x e)
' 134 #("bar" 42)
' 135 </pre>
' 136 </p>
' 137
' 138
' 139 <h2>Affected By:</h2>
' 140
' 141 <p>None.</p>
' 142
' 143
' 144 <h2>Exceptional Situations:</h2>
' 145
' 146 <p>Unifying an ARRAY-TEMPLATE against a non-ARRAY object results in
' 147 an UNIFICATION-FAILURE error being signaled.</p>
' 148
' 149
' 150 <h2>See Also:</h2>
' 151
' 152 <p>UNIFY</p>
' 153
' 154 <h2>Notes:</h2>
' 155
' 156 <h3>Syntax Note</h3>
' 157
' 158 <p>The ARRAY-TEMPLATE syntax tries to be easy to use, at the cost of
' 159 being overloaded. There is no actual need to have the separate
' 160 forms <code>(<b>array</b> (fixnum) ...)</code> and
' 161 <code>((<b>array</b> fixnum) ...)</code>.</p>
' 162
' 163 <p>In a future release they may be conflated. For the time being
' 164 they are kept separate as it is unclear which would be better to
' 165 provide.</p>
' 166
' 167 <h3>Elements Unification</h3>
' 168
' 169 <p>It would be nice to have the possibility to unify against
' 170 <em>slices</em> of the array. Alas, this seems non trivial to get
' 171 right, and it is left as a future extension of the semantics of
' 172 <i>&lt;shape-template&gt;</i>.</p>
' 173
' 174 <h3>ARRAY Structural Properties</h3>
' 175
' 176 <p>There is no way to "unify" against structural properties of
' 177 vectors like fill pointers and displacements.</p>
' 178
' 179
' 180 </td>
' 181
' 182 <!-- <td height="100%">&nbsp;</td> -->
' 183 </tr>
' 184
' 185 <tr height="100%">
' 186 <td height="100%">&nbsp;</td>
' 187 <td valign="top" width="80%" height="100%">
' 188
' 189 <div class="content">
' 190 <div class="text" style="padding-top: 10px;">
' 191
' 192 <h1>News</h1>
' 193
' 194 <p>News in chronological order, most recent on top.
' 195 </p>
' 196
' 197 <ul>
' 198 <li><strong>2004-10-30</strong><br>
' 199 Completed description.
' 200 </li>
' 201
' 202 </ul>
' 203
' 204 </div>
' 205 </div>
' 206
' 207 </td>
' 208
' 209 <td height="100%">&nbsp;</td>
' 210 </tr>
' 211
' 212
' 213
' 214
' 215 <tr>
' 216 <td colspan="3" valign="bottom" align="right">
' 217 <div class="copyright">
' 218 &copy; 2003-2004, Marco Antoniotti, all rights reserved.
' 219 </div>
' 220 </td>
' 221 </tr>
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' 223 </table>
' 224 </body>
' 225 </html>
' 226
' 227 <!-- end of file -- expression-template-class.html -->