The general rules of syntax are:
The "((" and "))" must appear on the same line of text.
White space inside is ignored. The template file is treated as a continuous character sequence include newline characters with the exception of control tokens which must be on one line.
Variable and control names are case insensitive.
Ending a control sequence with "*" suppresses the next newline. (i.e. ((IF_ZERO*)), ((DO abc*)) ...)
Ending a control sequence with "-" prevents the echoing out of the sequence if it is unknown. (i.e. ((ABC-)), ((DO ABC-)) ...)
Ending a control sequence with "+" causes any interior single quote mark " to be replaced by a pair of quote marks "". (i.e. ((ABC+)) )
Anywhere a variable can be placed a string constant "xxx" can be used.