USERADD will allow for a user written procedure to scan
lines entered using the EDIT/3000 ADD command (see Section III for a description of the ADD command).
This procedure is invoked if logical 2 or 3 (or TRUE) has been returned from USERINIT when an EDIT/3000 process is initiated. If this is the case, then USERADD is called after the final carriage return (that is,
one which does not follow an ampersand continuation character) each time a line of text has been entered using the ADD command.)
The parameters for this procedure are as described in paragraph 6-1. STRING contains the characters of a line entered in the ADD mode. As for USERCOMMAND, line continuation (&) has been processed. If tabs
are in use, they are not yet expanded into spaces; that is, the tab character has not been replaced by spaces in the STRING array. Note that if the user written procedure changes the length of the line, then it must
also change the value of LENGTH accordingly.
If FALSE is returned, the line of text will be rejected and the user will be prompted with the line number unless ADDQ was used. It is the procedure's responsibility to inform the user that the input was not accepted and to issue any diagnostic messages, The line is accepted if TRUE is returned. See the example in paragraph 6-5.
