make sure an error is set before printing it
Merge pull request #287 from satta/addintrons-debug

make sure an error is set before printing it
update error message
cosmetics
add class(es) for sorted set of distinct numbers
use generated code instead of makros
Merge pull request #285 from Garonenur/intset

Add Intset
add GT-Prefix to Makros
Merge pull request #288 from Garonenur/intset

add GT-Prefix to Makros