a very good and best study material covering all the important points.

3. THE ROLE OF THE PARSER Lexical Analyzer Parser source program token get next token parse tree Symbol table

20. Ambiguity – “dangling else ” stmt  if expr then stmt | if expr then stmt else stmt | other stmts if E 1 then if E 2 then S 1 else S 2 stmt if expr then stmt else stmt E 1 if expr then stmt S 2 E 2 S 1 stmt if expr then stmt E 1 if expr then stmt else stmt E 2 S 1 S 2 1 2

23. Immediate Left-Recursion A  A  |  where  does not start with A  eliminate immediate left recursion A   A ’ A ’   A ’ |  an equivalent grammar A  A  1 | ... | A  m |  1 | ... |  n where  1 ...  n do not start with A  eliminate immediate left recursion A   1 A ’ | ... |  n A ’ A ’   1 A ’ | ... |  m A ’ |  an equivalent grammar In general,

24. Immediate Left-Recursion -- Example E  E+T | T T  T*F | F F  id | (E) E  T E ’ E ’  +T E ’ |  T  F T ’ T ’  *F T ’ |  F  id | (E)  eliminate immediate left recursion

37. Non-Recursive Predictive Parsing Predictive Parsing Program Parsing Table M a + b $ X Y Z $ INPUT OUTPUT STACK

43. LL(1) Parser – Example1 Outputs: S  aBa B  bB B  bB B   Derivation(left-most): S  aBa  abBa  abbBa  abba S B a a B B b b  parse tree

44. LL(1) Parser – Example2 E  TE ’ E ’  +TE ’ |  T  FT ’ T ’  *FT ’ |  F  (E) | id E  E+T | T T  T*F | F F  id | (E) Input : id +id F  (E) F  id F T ’   T ’   T ’  *FT ’ T ’   T ’ T  FT ’ T  FT ’ T E ’   E ’   E ’  +TE ’ E ’ E  TE ’ E  TE ’ E $ ) ( * + id

53. LL(1) PARSING TABLE F  (E) F  id F T ’   T ’   T ’  *FT ’ T ’   T ’ T  FT ’ T  FT ’ T E ’   E ’   E ’  +TE ’ E ’ E  TE ’ E  TE ’ E $ ) ( * + id

60. Panic-Mode Error Recovery in LL(1) Parsing example synch synch F  (E) synch synch F  id F T ’   T ’   T ’  *FT ’ T ’   T ’ synch synch T  FT ’ synch T  FT ’ T E ’   E ’   E ’  +TE ’ E ’ synch synch E  TE ’ E  TE ’ E $ ) ( * + id

79. LR Parsing Algorithm stack input output S 0 X 1 S 1 . . X m-1 S m-1 X m S m $ a n ... a i ... a 1 Goto Table non-terminal s t each item is a a state number t e s Action Table terminals and $ s t four different a actions t e s LR Parsing Algorithm

82. (SLR) Parsing Tables for Expression Grammar Action Table Goto Table 1) E  E+T 2) E  T 3) T  T*F 4) T  F 5) F  (E) 6) F  id r3 r3 r3 r3 10 r5 r5 r5 r5 11 r1 r1 s7 r1 9 s11 s6 8 10 s4 s5 7 3 9 s4 s5 6 r6 r6 r6 r6 5 3 2 8 s4 s5 4 r4 r4 r4 r4 3 r2 r2 s7 r2 2 acc s6 1 3 2 1 s4 s5 0 F T E $ ) ( * + id state

90. Transition Diagram (DFA) of Goto Function I 0 I 1 I 2 I 3 I 4 I 5 I 6 I 7 I 8 to I 2 to I 3 to I 4 I 9 to I 3 to I 4 to I 5 I 10 to I 4 to I 5 I 11 to I 6 to I 7 id ( F * E E + T T T ) F F F ( id id ( * ( id +

92. Parsing Tables of Expression Grammar Action Table Goto Table r3 r3 r3 r3 10 r5 r5 r5 r5 11 r1 r1 s7 r1 9 s11 s6 8 10 s4 s5 7 3 9 s4 s5 6 r6 r6 r6 r6 5 3 2 8 s4 s5 4 r4 r4 r4 r4 3 r2 r2 s7 r2 2 acc s6 1 3 2 1 s4 s5 0 F T E $ ) ( * + id state

103. d S->.S,$ S->.CC,$ C->.cC,c/d C->.d,c/d I 0 C->d.,c/d I 4 S->C.C,$ C->.Cc,$ C->.d,$ I 2 C->c.C,$ C->.cC,$ C->.d,$ I 6 S->CC.,$ I 5 C->.cC.,$ I 9 C->d.,$ I 7 C->cC.,c/d I 8 C->c.C,c/d C->.cC,c/d C->.d,c/d I 3 S’->S.,$ I 1 S C C C c d C c d c c

104. CLR PARSING TABLE r2 9 r2 r2 8 r3 7 9 s7 s6 6 r1 5 r3 r3 4 8 s4 s3 3 5 s7 s6 2 acc 1 2 1 s4 s3 0 C S $ d c goto action STATE

110. LALR PARSING TABLE r2 r2 r2 89 r1 5 r3 r3 r3 47 89 s47 s36 36 5 s47 s36 2 acc 1 2 1 s47 s36 0 C S $ d c goto action STATE