diff -r c493eaba6018 -r 65731df141a5 marking4/output
--- a/marking4/output	Wed Oct 30 12:47:10 2019 +0000
+++ b/marking4/output	Wed Oct 30 14:07:58 2019 +0000
@@ -1,46 +1,95 @@
 
 Below is the feedback and provisional marks for your submission
-for assignment 9 Part 2.  Please note all marks are provisional until
+for the core part of assignment 9.  Please note all marks are provisional until
 ratified by the assessment board -- this is not an official
 results transcript.
 
-postfix.scala does not contain vars, returns, Arrays, ListBuffers etc?
+re.scala does not contain vars, returns, Arrays, ListBuffers etc?
   --> success
-postfix.scala runs?
+re.scala runs?
   --> success
- syard(split("3 + 4 * ( 2 - 1 )")) == List("3", "4", "2", "1", "-", "\*", "+")
- syard(split("( ( ( 3 ) ) + ( ( 4 + ( 5 ) ) ) )")) == List("3", "4", "5", "+", "+")
- syard(split("5 + 7 / 2")) == List("5", "7", "2", "/", "+")
- syard(split("5 * 7 / 2")) == List("5", "7", "\*", "2", "/")
+ nullable(ZERO) == false
+ nullable(ONE) == true
+ nullable(CHAR('a')) == false
+ nullable(ZERO | ONE) == true
+ nullable(ZERO | CHAR('a')) == false
+ nullable(ONE ~  ONE) == true
+ nullable(ONE ~ CHAR('a')) == false
+ nullable(STAR(ZERO)) == true
   --> success
- compute(syard(split("3 + 4 * ( 2 - 1 )"))) == 7
- compute(syard(split("10 + 12 * 33"))) == 406
- compute(syard(split("( 5 + 7 ) * 2"))) == 24
- compute(syard(split("5 + 7 / 2"))) == 8
- compute(syard(split("5 * 7 / 2"))) == 17
- compute(syard(split("9 + 24 / ( 7 - 3 )"))) == 15
-  --> success
-postfix2.scala does not contain vars, returns, Arrays, ListBuffers etc?
-  --> success
-postfix2.scala runs?
+ der('a', ZERO | ONE) == (ZERO | ZERO)
+ der('a', (CHAR('a') | ONE) ~ CHAR('a')) == ALT((ONE | ZERO) ~ CHAR('a'), ONE)
+ der('a', (CHAR('a') | CHAR('a')) ~ CHAR('a')) == (ONE | ONE) ~ CHAR('a')
+ der('a', STAR(CHAR('a'))) == (ONE ~ STAR(CHAR('a')))
+ der('b', STAR(CHAR('a'))) == (ZERO ~ STAR(CHAR('a')))
+
+ val r0 = "a" ~ "b" ~ "c"
+ assert(der('a', r0) == (ONE ~ "b") ~ "c")
+ assert(der('b', r0) == (ZERO ~ "b") ~ "c")
+ assert(der('c', r0) == (ZERO ~ "b") ~ "c")
+
+ val r1 = (ONE ~ "b") ~ "c"
+ assert(der('a', r1) == ((ZERO ~ "b") | ZERO) ~ "c")
+ assert(der('b', r1) == ((ZERO ~ "b") | ONE) ~ "c")
+ assert(der('c', r1) == ((ZERO ~ "b") | ZERO) ~ "c")
+
+ val r2 = ((ZERO ~ "b") | ONE) ~ "c"
+ assert(der('a', r2) == ((((ZERO ~ "b") | ZERO) ~ "c") | ZERO))
+ assert(der('b', r2) == ((((ZERO ~ "b") | ZERO) ~ "c") | ZERO))
+ assert(der('c', r2) == ((((ZERO ~ "b") | ZERO) ~ "c") | ONE))
   --> success
- syard(split("3 + 4 * ( 2 - 1 )")) == List("3", "4", "2", "1", "-", "\*", "+")
- syard(split("( ( ( 3 ) ) + ( ( 4 + ( 5 ) ) ) )")) == List("3", "4", "5", "+", "+")
- syard(split("5 + 7 / 2")) == List("5", "7", "2", "/", "+")
- syard(split("5 * 7 / 2")) == List("5", "7", "\*", "2", "/")
- syard(split("3 + 4 * 8 / ( 5 - 1 ) ^ 2 ^ 3")) == 
-         List("3", "4", "8", "\*", "5", "1", "-", "2", "3", "^", "^", "/", "+")
- 
- compute(syard(split("3 + 4 * ( 2 - 1 )"))) == 7
- compute(syard(split("10 + 12 * 33"))) == 406
- compute(syard(split("( 5 + 7 ) * 2"))) == 24
- compute(syard(split("5 + 7 / 2"))) == 8
- compute(syard(split("5 * 7 / 2"))) == 17
- compute(syard(split("9 + 24 / ( 7 - 3 )"))) == 15
- compute(syard(split("4 ^ 3 ^ 2"))) == 262144
- compute(syard(split("4 ^ ( 3 ^ 2 )"))) == 262144
- compute(syard(split("( 4 ^ 3 ) ^ 2"))) == 4096
- compute(syard(split("( 3 + 1 ) ^ 2 ^ 3"))) == 65536
+ simp(ZERO | ONE) == ONE
+ simp(STAR(ZERO | ONE)) == STAR(ZERO | ONE)
+ simp(ONE ~ (ONE ~ (ONE ~ CHAR('a')))) == CHAR('a')
+ simp(((ONE ~ ONE) ~ ONE) ~ CHAR('a')) == CHAR('a')
+ simp(((ONE | ONE) ~ ONE) ~ CHAR('a')) == CHAR('a')
+ simp(ONE ~ (ONE ~ (ONE ~ ZERO))) == ZERO
+ simp(ALT(ONE ~ (ONE ~ (ONE ~ ZERO)), CHAR('a'))) == CHAR('a')
+ simp(CHAR('a') | CHAR('a')) == CHAR('a')
+ simp(CHAR('a') ~ CHAR('a')) == CHAR('a') ~ CHAR('a')
+ simp(ONE | CHAR('a')) == (ONE | CHAR('a'))
+ simp(ALT((CHAR('a') | ZERO) ~ ONE,
+          ((ONE | CHAR('b')) | CHAR('c')) ~ (CHAR('d') ~ ZERO))) == CHAR('a')
+ simp((ZERO | ((ZERO | ZERO) | (ZERO | ZERO))) ~ ((ONE | ZERO) | ONE ) ~ (CHAR('a'))) == ZERO
+ simp(ALT(ONE | ONE, ONE | ONE)) == ONE
+ simp(ALT(ZERO | CHAR('a'), CHAR('a') | ZERO)) == CHAR('a')
   --> success
-Overall mark for CW 9, Part 2
-4
+ val EVIL = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))
+ ders(("a" * 5).toList,EVIL) == SEQ(SEQ(STAR(CHAR('a')),STAR(STAR(CHAR('a')))),CHAR('b'))
+ ders(List('b'),EVIL) == ONE
+ ders(List('b','b'),EVIL) == ZERO
+ matcher(EVIL, "a" * 5 ++ "b") == true
+ matcher(EVIL, "a" * 50 ++ "b") == true
+ matcher(EVIL, "a" * 50) == false
+ matcher(EVIL, "b") == true
+ matcher(EVIL, "bb") == false
+ matcher("abc", "abc") == true
+ matcher("abc", "ab") == true
+ matcher(("ab" | "a") ~ (ONE | "bc"), "abc") == true
+ matcher(ONE, "") == true
+ matcher(ZERO, "") == false
+ matcher(ONE | CHAR('a'), "") == true
+ matcher(ONE | CHAR('a'), "a") == true
+  --> success
+ val EVIL = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))
+ size(der('a', der('a', EVIL))) == 28
+ size(der('a', der('a', der('a', EVIL)))) == 58
+ size(ders("aaaaaa".toList, EVIL)) == 8
+ size(ders(("a" * 50).toList, EVIL)) == 8
+  --> success
+ simp(Iterator.iterate(ONE:Rexp)(r => SEQ(r, ONE | ONE)).drop(50).next) == ONE
+    ...the Iterator produces the rexp
+
+      SEQ(SEQ(SEQ(..., ONE | ONE) , ONE | ONE), ONE | ONE)
+
+    where SEQ is nested 50 times.
+
+ simp(Iterator.iterate(ONE:Rexp)(r => ALT(r, r)).drop(20).next) == ONE
+    ... the Iterator produces a rexp of size 2097151
+
+ val EVIL = SEQ(STAR(STAR(CHAR('a'))), CHAR('b'))
+ matcher(EVIL, "a" * 1000000 ++ "b") == true
+ matcher(EVIL, "a" * 1000000) == false
+  --> success
+Overall mark for CW 9, Core Part
+6