Consider the following CFG G = (V, , R, P), where: V = {P, Type, Pl,...

 

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Consider the following CFG G = (V, , R, P), where: V = {P, Type, Pl, PI1, Body, St, Else} ={main, (,), int, char, void, {,},;,,,=, if, exp, else, id } RP >Type main (PI) { Body } Type >int | char | void Pl-> | id Pl1 Pl1 ->, id Pl1 | Body >St; Body | St; St -> id = exp St-> if (exp) St Else | if (exp) { Body } Else } Else -> else St | else { Body } | E Some groups of production rules describe particular language features. E.g., the rule: "P-> Type main (PI) { Body}" describes the overall structure of programs. The rules for variables PI and PI1 describe parameter lists. The rules for variables St and Else describe the assignment statement and if statements. Some of these language features could be represented using only a DFA or equivalent model; while some features can only be described correctly using the Context Free Grammar (CFG) model. 1.c. [2 points] Identify the language feature(s) which require the CFG model and very briefly explain why they require a CFG to define them. Consider the following CFG G = (V, , R, P), where: V = {P, Type, Pl, PI1, Body, St, Else} ={main, (,), int, char, void, {,},;,,,=, if, exp, else, id } RP >Type main (PI) { Body } Type >int | char | void Pl-> | id Pl1 Pl1 ->, id Pl1 | Body >St; Body | St; St -> id = exp St-> if (exp) St Else | if (exp) { Body } Else } Else -> else St | else { Body } | E Some groups of production rules describe particular language features. E.g., the rule: "P-> Type main (PI) { Body}" describes the overall structure of programs. The rules for variables PI and PI1 describe parameter lists. The rules for variables St and Else describe the assignment statement and if statements. Some of these language features could be represented using only a DFA or equivalent model; while some features can only be described correctly using the Context Free Grammar (CFG) model. 1.c. [2 points] Identify the language feature(s) which require the CFG model and very briefly explain why they require a CFG to define them.