1 <html> 2 <head> 3 <title>CL Unification: Class ELT-TEMPLATE</title> 4 <link rel="stylesheet" href="main.css"> 5 </head> 6 7 <body marginheight="0" marginwidth="0" leftmargin="0" topmargin="0" bgcolor="#ffffff"> 8 9 <table border="0" cellpadding="0" cellspacing="0" width="100%" height="100%" vspace="0" hspace="0"> 10 <tr> 11 <td colspan="3"> 12 <div class="header" 13 style="font-family:=Verdana,Arial,Helvetica; font-size: 18px; color: #41286f;"> 14 <strong><i>CL Unification: Class ELT-TEMPLATE</title></i></strong> 15 <div class="navigation"> 16 <a href="index.html" class="navigation-link">Home</a> 17 | <a href="unification-package.html" class="navigation-link">Previous</a> 18 | <a href="index.html" class="navigation-link">Next</a> 19 | <a href="downloads.html" class="navigation-link">Downloads</a> 20 | <a href="links.html" class="navigation-link">Links</a> 21 </div> 22 </div> 23 <div class="black-line"><img src="images/shim.gif" height="1" width="1"></div> 24 <div class="middle-bar"><img src="images/shim.gif" height="5" width="1"></div> 25 <div class="black-line"><img src="images/shim.gif" height="1" width="1"></div> 26 </td> 27 </tr> 28 29 <tr height="100%"> 30 <td height="100%"> </td> 31 <td valign="top" width="80%" height="100%"> 32 33 <div class="content"> 34 <div class="text" style="padding-top: 10px;"> 35 36 <h1><i>Class</i> <strong>ELT-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 ELT-TEMPLATE, ELEMENT-TEMPLATE, EXPRESSION-TEMPLATE, TEMPLATE, STANDARD-OBJECT, T. 47 </p> 48 49 <h2>Known Subclasses:</h2> 50 51 <p> 52 None. 53 </p> 54 55 56 <h2>Slots:</h2> 57 58 <p>None.</p> 59 60 61 <h2>Description:</h2> 62 63 <p>The ELT-TEMPLATE class denotes those object that are used 64 to unify against a particular element of a SEQUENCE.</p> 65 66 <h3>Template Syntax:</h3> 67 68 <p> 69 <pre> 70 #T(<b>elt</b> <i>index</i> <i>item</i>) 71 </pre> 72 </p> 73 74 <p>The ELT-TEMPLATE syntax denotes the element of <i>item</i> at 75 <i>index</i>. An ELT-TEMPLATE must be unified against a SEQUENCE 76 object. <i>item</i> is <em>unified</em> against the element 77 extracted from the sequence object at <i>index</i> by the standard 78 function ELT.<p> 79 80 81 <h2>Examples:</h2> 82 83 <p> 84 <pre> 85 cl-prompt> (setf e (unify #(0 1 42 3 4 5) #T(<b>elt</b> 2 ?x))) 86 #<ENVIRONMENT xxx> 87 88 cl-prompt> (find-variable-value '?x e) 89 42 90 91 cl-prompt> (setq e (unify #(0 1 42 3 4 5) #T(<b>elt</b> 42 ?x))) 92 --> Error: index 42 out of bounds. 93 94 95 cl-prompt> (setq e (unify 42 #T(<b>elt</b> 42 ?x))) 96 --> Error: UNIFICATION-FAILURE 97 98 99 cl-prompt> (setq e (unify "This is a string!" #T(<b>elt</b> 4 ?x))) 100 #<ENVIRONMENT xxx> 101 102 cl-prompt> (find-variable-value '?x e) 103 #\Space 104 </pre> 105 </p> 106 107 108 109 110 <h2>Affected By:</h2> 111 112 <p>None.</p> 113 114 115 <h2>Exceptional Situations:</h2> 116 117 <p>Unifying an ELT-TEMPLATE against a non-SEQUENCE object results in 118 an UNIFICATION-FAILURE error being signaled.</p> 119 120 121 <h2>See Also:</h2> 122 123 <p>UNIFY</p> 124 125 <h2>Notes:</h2> 126 127 <p>None.</p> 128 129 </td> 130 131 <!-- <td height="100%"> </td> --> 132 </tr> 133 134 <tr height="100%"> 135 <td height="100%"> </td> 136 <td valign="top" width="80%" height="100%"> 137 138 <div class="content"> 139 <div class="text" style="padding-top: 10px;"> 140 141 <h1>News</h1> 142 143 <p>News in chronological order, most recent on top. 144 </p> 145 146 <ul> 147 <li><strong>2004-06-11</strong><br> 148 Completed description. 149 </li> 150 151 </ul> 152 153 </div> 154 </div> 155 156 </td> 157 158 <td height="100%"> </td> 159 </tr> 160 161 162 163 164 <tr> 165 <td colspan="3" valign="bottom" align="right"> 166 <div class="copyright"> 167 © 2003-2004, Marco Antoniotti, all rights reserved. 168 </div> 169 </td> 170 </tr> 171 172 </table> 173 </body> 174 </html> 175 176 <!-- end of file -- expression-template-class.html -->