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LR parser

LR parser. Types of LR Parser. LR Parser SLR(1) or LR(0) CLR or LR(1) LALR. Construct LR parser for given grammer. E->E+T E->T T->T*F T->F F->(E) F->id. Take first production rule in I o state

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LR parser

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  1. LR parser

  2. Types of LR Parser • LR Parser • SLR(1) or LR(0) • CLR or LR(1) • LALR

  3. Construct LR parser for given grammer • E->E+T • E->T • T->T*F • T->F • F->(E) • F->id

  4. Take first production rule in Io state • Then if rule A->a.Bb is a rule and B->c/d is production then then add B->.c , B->.d in closure. • In I4 state don’t expand E->.T because I2 have same one.No need to apply it. I1 I2 I3 I4 I5

  5. CLR or LR(1) • S->CC • C->aC • C->d

  6. In first production add $ as its canonical collection. • If production is [A->aBb, a1] & if there is production B->.b1,c then add B->.b1,c c belongs to First(b a1) Here S’->.S null,$ so first (null $) is $ that’s why S->.CC,$ Here C->.aC So first (C)={a,d} first(C $)={a,d} that’s why C->.aC,a/d No need to expand I3 =goto(I3,a)

  7. LALR CLR

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