<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >string-index</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="DSSSL Library Reference" HREF="index.html"><LINK REL="UP" TITLE="Miscellaneous" HREF="r300.htm"><LINK REL="PREVIOUS" TITLE="trim-string" HREF="trim-string.html"><LINK REL="NEXT" TITLE="parse-pi-attribute" HREF="parse-pi-attribute.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >DSSSL Library Reference: Part of the Modular DocBook Stylesheet distribution</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="trim-string.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="parse-pi-attribute.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="STRING-INDEX" ></A >string-index</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1987" ></A ><H2 >Name</H2 >string-index -- Finds first occurance of 'target' in 'source'</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1990" ></A ><H2 >Synopsis</H2 ><PRE CLASS="SYNOPSIS" >(string-index source target)</PRE ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1993" ></A ><H2 >Description</H2 ><P >Returns the position of the first occurance of <TT CLASS="LITERAL" >target</TT > in <TT CLASS="LITERAL" >source</TT >, or -1 if it does not occur.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1998" ></A ><H2 >Author</H2 ><P >Norman Walsh, <ndw@nwalsh.com></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2001" ></A ><H2 >Source Code</H2 ><PRE CLASS="PROGRAMLISTING" >(define (string-index source target) ;; Finds first occurance of 'target' in 'source' (let loop ((str source) (pos 0)) (if (< (string-length str) (string-length target)) -1 (if (string=? (substring str 0 (string-length target)) target) pos (loop (substring str 1 (string-length str)) (+ pos 1))))))</PRE ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="trim-string.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="parse-pi-attribute.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >trim-string</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="r300.htm" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >parse-pi-attribute</TD ></TR ></TABLE ></DIV ></BODY ></HTML >