afl-material: progs/app6.scala@f54972b0f641 (annotated)

117 25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	1	def der (r: Rexp, c: Char) : Rexp = r match {
7 73cf4406b773 updated Christian Urban <urbanc@in.tum.de> parents: diff changeset	2	case NULL => NULL
73cf4406b773 updated Christian Urban <urbanc@in.tum.de> parents: diff changeset	3	case EMPTY => NULL
73cf4406b773 updated Christian Urban <urbanc@in.tum.de> parents: diff changeset	4	case CHAR(d) => if (c == d) EMPTY else NULL
117 25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	5	case ALT(r1, r2) => ALT(der(r1, c), der(r2, c))
7 73cf4406b773 updated Christian Urban <urbanc@in.tum.de> parents: diff changeset	6	case SEQ(r1, r2) =>
117 25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	7	if (nullable(r1)) ALT(SEQ(der(r1, c), r2), der(r2, c))
25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	8	else SEQ(der(r1, c), r2)
25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	9	case STAR(r) => SEQ(der(r, c), STAR(r))
7 73cf4406b773 updated Christian Urban <urbanc@in.tum.de> parents: diff changeset	10	}
73cf4406b773 updated Christian Urban <urbanc@in.tum.de> parents: diff changeset	11
117 25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	12	def ders (s: List[Char], r: Rexp) : Rexp = s match {
25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	13	case Nil => r
25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	14	case c::s => ders(s, der(c, r))
25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	15	}
25999de692b2 added slides Christian Urban <christian dot urban at kcl dot ac dot uk> parents: 93 diff changeset	16

author	Christian Urban <christian dot urban at kcl dot ac dot uk>
	Fri, 22 Nov 2013 16:56:51 +0000
changeset 198	f54972b0f641
parent 117	25999de692b2
child 262	ee4304bc6350
permissions	-rw-r--r--