Consider the following grammar and the semantic actions to support the inherited type declaration attributes. Let X_{1}, X_{2}, X_{3} X_{4}, X_{5}, and X_{6} be the placeholders for the non-terminals {D}, {T}, {L} or {L} 1 in the following table:Production rule Semantic action {D} → {TL}X_{1} . type =X_{2}.type {T} → intT.type = intT.type = intt.type = float {L} → {L}_{1}, idX3.type =X 4.type and Type (id.type, {X}_{5}.type) {L} → {id}add Type(id.entry, X_{6}.type)Which one of the following are the appropriate choices for X_{1}, X_{2}, X_{3} and X_{4} ?

Question

Consider the following grammar and the semantic actions to support the inherited type declaration attributes. Let X_{1}, X_{2}, X_{3} X_{4}, X_{5}, and X_{6} be the placeholders for the non-terminals  {D},  {T},  {L} or  {L} 1 in the following table:Production rule Semantic action {D} →  {TL}X_{1} . type =X_{2}.type {T} → intT.type = intT.type = intt.type = float {L} →  {L}_{1}, idX3.type =X 4.type and Type (id.type,  {X}_{5}.type) {L} →  {id}add Type(id.entry, X_{6}.type)Which one of the following are the appropriate choices for X_{1}, X_{2}, X_{3} and X_{4} ?

Examsnet · Accepted Answer

Correct Answer is : X1=L,X2=T,X3=L1,X4=L

Production rule	Semantic action
D→TL	X1. type =X2.type
T→ int	T.type = int
T.type = int	t.type = float
L→L1, id	X3.type =X4.type and Type (id.type, X5.type)
L→id	add Type(id.entry, X6.type)

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