If you specify length, it must be a positive whole number or zero. The default for length is the number of characters in info.
ABBREV('Print','Pri') -> 1
ABBREV('PRINT','Pri') -> 0
ABBREV('PRINT','PRI',4) -> 0
ABBREV('PRINT','PRY') -> 0
ABBREV('PRINT','') -> 1
ABBREV('PRINT','',1) -> 0
say 'Enter option:'; pull option .
select /* keyword1 is to be the default */
when abbrev('keyword1',option) then ...
when abbrev('keyword2',option) then ...
...
otherwise nop;
end;