129 

   129 

   130 // given a regular expression and building successive

   130 // given a regular expression and building successive

   131 // derivatives might result into bigger and bigger

   131 // derivatives might result into bigger and bigger

   132 // regular expressions...here is an example for this:

   132 // regular expressions...here is an example for this:

   133 

   133 

   134 val BIG_aux = STAR(ALT(CHAR('a'), CHAR('b')))

   135 val BIG_aux = STAR(ALT(CHAR('a'), CHAR('b')))

   135 val BIG = SEQ(BIG_aux, SEQ(CHAR('a'),SEQ(CHAR('b'), BIG_aux)))

   136 val BIG = SEQ(BIG_aux, SEQ(CHAR('a'),SEQ(CHAR('b'), BIG_aux)))

   136 

   137 

   137 size(ders("".toList, BIG))              // 13

   138 size(ders("".toList, BIG))              // 13

   138 size(ders("ab".toList, BIG))            // 51

   139 size(ders("ab".toList, BIG))            // 51