Indexing helps you target a particular place within a piece of text. For example, if you want to mark a particular word in bold, red, or in a different font size, you can do so if you know the index of the starting point and the index of the endpoint that needs to be targeted.
The index must be specified in one of the following formats:
| The index format | Description |
| x.y | This refers to the character at row x and column y. |
| @x,y | This refers to the character that covers the x,y coordinate within the text's window. |
| end | This refers to the end of the text. |
| mark | This refers to the character after a named mark. |
| tag.first | This refers to the first character in the text that has been tagged with a given tag. |
| tag.last | This refers to ... |
