Top-down Parsing (ASU Ch 4.4) Predictive Parsers (ASU 4.4 ...

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First: example (ASU Ex 4.17) E TE’ E’ +TE’ | ¤ T FT’ T’ *FT’ | ¤ F (E) | id • first(E) = first(T) = first(F) = {(, id} – from F (E) | id; T FT’; E TE’ • first(E’) = { +, ¤ } – from E’ +TE’ | ¤ • + is a terminal • E’ ¤ • first(T’) = { *, ¤ } – from T’ *FT’ | ¤ • * is a terminal • T’ ¤ 10 14/10/2014 DFR - CC - TDP
First and Follow Sets (ASU Ch 4.4) • follow(X) – follow(S) += $ S: start symbol / $: end of input / S = w$ – if A => a B β sibling • follow(B) += first(β) except for ¤ – if in P : A => aB or A => aBβ and ¤ in first (β) • follow(B) += follow(A) (¤=empty) parent 11 14/10/2014 DFR - CC - TDP
Page 1 and 2: Top-down Parsing (ASU Ch 4.4) • P
Page 3 and 4: Transition Diagrams (ASU pp183-185)
Page 5 and 6: Recursive Descent example L ::= E {
Page 7 and 8: Non Recursive Predictive Parser (NR
Page 9: First and Follow Sets (ASU Ch 4.4)
Page 13 and 14: Parsing Table M (ASU Fig 4.15 p188)
Page 15 and 16: Constructing the Parsing Table: Det
Page 17 and 18: Non Recursive Parsing Algorithm (AS
Page 19 and 20: Properties of LL(1) Grammars (ASU C

Top-down Parsing (ASU Ch 4.4) Predictive Parsers (ASU 4.4 ...

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