- LL -

LL
( )
−
−( )

LR
( )
−
( )
−
− SLR LALR LR ...

LL (1/3)
S → aBcd
B → bc
→b
abcd
−

LL (2/3)
A=Ax|y
A = y A'
A' = x A' | ε

LL (3/3)
A
A
A
A

LL (3/3)
A
A’
A’
A’
ε

LL (3/3)
LL
−
−
T E’ ) T’ E’ $ (i + i) * i $

LL (3/3)
E→E T
E T
T
T→T F
T F
F
F→ E
i
num

LL (3/3)
2
E → TE’
E’ → TE‘
TE‘
ε
T’ → FT‘
FT’
ε
F→ E
i
num

LL (3/3)
DIRECTOR
−
FIRST
FOLLOW
DIRECTOR FIRST
FOLLOW

LL (3/3)
FIRST
FIRST(α)
−
α
ε
FIRST α a α∈T, α⇒a…
α α
a ε
a ∈ FIRST(α) ε ∈ FIRST(α)
FIRST F , i, num

LL (3/3)
FOLLOW
FOLLOW(A)
−
A
ε
, S ⇒…Aa…
FOLLOW A a a∈T∪
S
A
a $
a∈F ()
F F , , , , ,

LL (3/3)
DIRECTOR
,
−
a DIRECTOR A,α ,
−
A A→α
a DIRECTOR A,α DIRECTOR
−
A,β , LL( )
DIRECTOR A,α
−
a a∈T,a∈FIRST α ε
α⇒ε a∈FOLLOW(A)

LL (3/3)
DIRECTOR 2
A A
α α
a εa
a ∈ FIRST(α) ε a⇒ε

LL (3/3)
DIRECTOR 3
DIRECTOR(F, E ) FIRST( E ) ε
−
DIRECTOR(F,i) FIRST( ) ε {i}
−
DIRECTOR(F,num) FIRST num ε num
−
able[A,α] A→α a∈DIRECTOR(A,α)

LR
−
FIRST FOLLOW DIRECTOR
−

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