Task

 verify the version/revision of your currently running (compiler/interpreter/byte-compiler/runtime environment/whatever your language uses) and exit if it is too old.
 check whether the variable "bloop" exists and whether the math-function "abs()" is available and if yes compute abs(bloop).


Extra credit

 Report the number of integer variables in global scope, and their sum.


100 IF VERNUM<2.1 THEN PRINT "Version is too old.":STOP 
110 WHEN EXCEPTION USE ERROR
120   PRINT ABS(BLOOP)
130 END WHEN
140 HANDLER ERROR
150   PRINT EXSTRING$(EXTYPE)
160   CONTINUE
170 END HANDLER