Synopsis:
   $indextoitem(<array> <index number>)
   $itemtoindex(<array> <item number>)

Technical:
   These functions are used to convert between array item numbers are index
   numbers.

   Item numbers are counted incrementally as items are added to an array,
   starting at 0 (zero).  Each new item uses the next available item number;
   if there are 5 items in an array, the next item that may be added is item
   number 5 (remember that we count from zero... 5 items is 0..4).

   Index numbers represent each items position in the array when sorted.
   Items are sorted based on their ascii values.  This is generally
   alphabetical; however, since it is based on ascii values, all capital
   letters are sorted after all lowercase letters.  It follows a sorting
   algorithm similar to the $sort() function's.

Practical:
   The $indextoitem() function converts an index number in the given array
   to its corresponding item number; $itemtoindex() does just the opposite.
   This is mostly useful in conjunction with $igetitem() or $ifinditem(),
   allowing an array to be dealt with in a logical order.

Returns:
     -2   cannot find index/item number in array
     -1   cannot find named array
   > -1   item number corresponding to given index number (and vice verse)

Examples:
   $setitem(booya 0 hello)
   $setitem(booya 1 goodbye)
   $itemtoindex(booya 0)                 returns 1
   $indextoitem(booya 1)                 returns 0
   $itemtoindex(foobar 0)                returns -1
   $itemtoindex(booya 100)               returns -2

See Also:
   Arrays(7); ifinditem(6); igetitem(6); setitem(6); sort(6)

