====== Accessor ELT ====== ====Syntax==== * **elt** //sequence index// → //object// * (**setf** (**elt** //sequence index//) //new-object//) ====Arguments and Values==== * //sequence// - a //[[CL:Glossary:proper sequence]]//. * //index// - a //[[CL:Glossary:valid sequence index]]// for //sequence//. * //object// - an //[[CL:Glossary:object]]//. * //new-object// - an //[[CL:Glossary:object]]//. ====Description==== //[[CL:Glossary:access|Accesses]]// the //[[CL:Glossary:element]]// of //sequence// specified by //index//. ====Examples==== <blockquote> ([[CL:Macros:defparameter]] *str* ([[CL:Functions:copy-seq]] "0123456789")) <r>*STR*</r> (elt *str* 6) <r>#\6 </r> ([[CL:Macros:setf]] (elt *str* 0) #\#) <r>#\# </r> *str* <r>"#123456789" </r> </blockquote> ====Side Effects==== None. ====Affected By==== None. ====Exceptional Situations==== Should be prepared to signal an error of type type-error if //sequence// is not a //[[CL:Glossary:proper sequence]]//. Should signal an error of type type-error if //index// is not a //[[CL:Glossary:valid sequence index]]// for //sequence//. ====See Also==== * **[[CL:Functions:aref|Function AREF]]** * **[[CL:Functions:nth|Function NTH]]** * {\secref\ConstantModification} ====Notes==== **[[CL:Functions:aref]]** may be used to //[[CL:Glossary:access]]// //[[CL:Glossary:vector]]// elements that are beyond the //[[CL:Glossary:vector]]//'s //[[CL:Glossary:fill pointer]]//. \issue{CONSTANT-MODIFICATION:DISALLOW}