In IDL, lines starting with a ‘;’ are called comment lines. Comment lines are indented as follows:
|The indentation of lines starting with three semicolons remains
|Lines starting with two semicolons are indented like the surrounding code.
|Lines starting with a single semicolon are indented to a minimum column.
The indentation of comments starting in column 0 is never changed.
The indentation of a comment starting with this regexp will not be changed.