equal
  deleted
  inserted
  replaced
  
    
    
    29   case SEQ(r1, r2) =>   | 
    29   case SEQ(r1, r2) =>   | 
    30     if (nullable(r1)) ALT(SEQ(der(c, r1), r2), der(c, r2))  | 
    30     if (nullable(r1)) ALT(SEQ(der(c, r1), r2), der(c, r2))  | 
    31     else SEQ(der(c, r1), r2)  | 
    31     else SEQ(der(c, r1), r2)  | 
    32   case STAR(r1) => SEQ(der(c, r1), STAR(r1))  | 
    32   case STAR(r1) => SEQ(der(c, r1), STAR(r1))  | 
    33   case NTIMES(r, i) =>   | 
    33   case NTIMES(r, i) =>   | 
    34     if (i == 0) ZERO else SEQ(der(c, r), NTIMES(r, i - 1))  | 
    34     if (i == 0) ZERO else der(c, SEQ(r, NTIMES(r, i - 1)))  | 
    35 }  | 
    35 }  | 
    36   | 
    36   | 
    37 def simp(r: Rexp) : Rexp = r match { | 
    37 def simp(r: Rexp) : Rexp = r match { | 
    38   case ALT(r1, r2) => (simp(r1), simp(r2)) match { | 
    38   case ALT(r1, r2) => (simp(r1), simp(r2)) match { | 
    39     case (ZERO, r2s) => r2s  | 
    39     case (ZERO, r2s) => r2s  |