to get a program to return EXPR("%{1,2,3,3,4%}") as the set [1,2,3,4]

[compsystems]

PHP Code:

EXPORT exprprg1()
BEGIN
return expr("%{ a, a, b, c, c, d, ee, ee, ee,f %}");
END; 


exprprg1() returns "Error: Syntax Error" =(

another solution is to work on the CAS environment, you avoid being added CAS( )

PHP Code:

#cas
exprprg2():=
BEGIN
  return expr("%{ a, a, b, c, c, d, ee, ee, ee,f %}");
END;
#end 


exprprg2() returns set[a,b,c,d,ee,f]