<RefEntry id="component-list-child-number"> <!-- This file is generated automatically from the DSSSL source. --> <!-- Do not edit this file! --> <?html-filename component-list-child-number.html> <RefMeta> <RefEntryTitle>component-list-child-number</RefEntryTitle> <RefMiscInfo Role="file">dblib.dsl</RefMiscInfo> </RefMeta> <RefNameDiv> <RefName>component-list-child-number</RefName> <RefPurpose>Find child-number of a list of children within a component</RefPurpose> </RefNameDiv> <RefSynopsisDiv><Title>Synopsis</Title> <Synopsis> (component-list-child-number inputnd inputlist complist) </Synopsis> </RefSynopsisDiv> <RefSect1><Title>Description</Title> <para> Finds the first ancestor of <literal>inputnd</literal> in <literal>complist</literal> and then counts all the elements of the types in <literal>inputlist</literal> from that point on and returns the number of <literal>inputnd</literal>. </para> <para> If the node is not found, 0 is returned. </para> <para> WARNING: this requires walking over *all* the descendants of the ancestor node. This may be *slow*.</para> </RefSect1> <RefSect1><Title>Author</Title> <para> Norman Walsh, <ndw@nwalsh.com> </para> </RefSect1> <RefSect1><Title>Source Code</Title> <ProgramListing> (define (component-list-child-number inputnd inputlist complist) ;; Find child-number of a list of children within a component (let loop ((nl (component-list-descendant-node-list inputnd inputlist complist)) (num 1)) (if (node-list-empty? nl) 0 (if (node-list=? (node-list-first nl) inputnd) num (loop (node-list-rest nl) (+ num 1)))))) </ProgramListing> </RefSect1> </RefEntry>