$indextoword(<position> <text>)

• If the <position> argument is omitted the empty string is returned.
• If the <position> argument is a negative number the empty string is returned.
• If the <text> argument is omitted the empty string is returned.
• If the length of <text> is less than <position> the empty string is returned.
• Otherwise, the return value returns a value suitable for use with the $word() function (or other word functions) representing the word that contains the <position>th character which should be a value returned by $index() or the like.
• Remember that <position> counts from zero!
• Remember that the return value counts from zero!

The most obvious application of this function is to find the word on the input line underneath the cursor. $L is the contents of the input line and $curpos() tells you where the cursor is; you can then use something like this:

$word($indextoword($curpos() $L) $L)

to extract the word “underneath” the cursor. This is the fundamental mechanics of how tab completion scripts know what to complete.

A number suitable for use with the word manipulation functions that represents the word that contains the <position>th character in <text>. Both <position> and the return value count from zero.

$word($indextoword($curpos() $L) $L)   returns the word under the cursor
@ foo = [one two. three.]
$indextoword($index(. $foo) $foo)      returns 1 (the . in ``two.'')
$indextoword($rindex(. $foo) $foo)     returns 2 (the . in ``three.'')
$indextoword(100 testing)              returns the empty string