Practical Programming in Tcl & Tk, Third Edition

Text Indices

The characters in a text widget are addressed by their line number and the character position within the line. Lines are numbered starting at one, while characters are numbered starting at zero. The numbering for lines was chosen to be compatible with other programs that number lines starting at one, like compilers that generate line-oriented error messages. Here are some examples of text indices:

1.0	The first character.
1.1	The second character on the first line.
2.end	The newline character on the second line.

There are also symbolic indices. The insert index is the position at which new characters are normally inserted when the user types in characters. You can define new indices called marks, too, as described later. Table 33-1 summarizes ...