Sequence Object

This object allows a sequence to be created. Each object is its own sequence. For example, tables & figures could have their own sequence.

The sequence can be prefixed with a prefix. This prefix could be a chapter number. If no prefix is used, NULL ("") must be passed to the constructor.

For cross referencing, a tag can be passed in to .next(). The tag is is associated with the value. The value can be retrieved.

Object Definition

<script language="JavaScript1.1">
<!--
//Purpose: provide an incrementing counter a specific value can be tagged
//         for cross reference.
//
//Usage:   obj = new Counter("Opt_prefix")- Constructor for the object
//         val = obj.next("opt_tag")      - Creates a new number, attaches tag if given
//                                        - returns the same sequence num that getNum() does.
//         val = obj.getNum("tag");       - Returns the sequence number (including prefix)
function Sequence(prefix) {
    this.cur       = 0;
    this.pre       = prefix;
    this.next      = Next;
    this.getNum    = GetNum;
    this.tag       = new Array();
}

//Purpose: create a new value in the sequence (see Sequence object)
function Next(name) {
    this.cur++;
    if (name != "") {
      this.tag[this.cur] = name;
    }
    return (this.pre + this.cur);
}

//Purpose: returns the sequence number for a given tag (see Sequence object)
function GetNum(tag) {
    for (var i = 1; i < this.tag.length; i++) {
      if (tag == this.tag[i]) return(this.pre + i);
    }
    return (this.pre + "?");
}
//-->
</script>

Example Usage

Code Output

<script language="JavaScript1.1">
<!--
with (document) {
var seq = new Sequence("");

seq.next("");
var seq1 = new Sequence("");

    write("No prefix<br>");
    write(seq1.next() + "<br>");
    write(seq1.next() + "<br>");
    write(seq1.next() + "<br>");

seq.next("seq2");
var seq2 = new Sequence(seq.getNum("seq2") + "-");

    write("<br>Prefix from value in an other sequence<br>");
    write(seq2.next() + "<br>");
    write(seq2.next() + "<br>");
    write(seq2.next() + "<br>");
}
// -->
</script>

Last Updated: $Date: 2002/03/25 06:35:54 $ GMT ($Revision: 1.5 $)