15) Augment the CFG given in the notes to add simple switch state- ments, descri

Question

15) Augment the CFG given in the notes to add simple switch state-

ments, described informally below. Also provide a short description of

any ambiguities or shortcomings of the informal description, and how you

chose to address them in your grammar (i.e., you are allowed to have your

grammar generate etter" switch statements than what are described).

You may assume the appropriate nonterminals and terminals have been

added, and that the production [stmt]->[switch] has been added to

the set of productions. So you need only give the productions relevant

to switch statements themselves; you do not need to copy out the whole

grammar.

A switch statement begins with the keyword switch, followed by a variable name, and then a list of cases delimited (surrounded)

by the keywords begin and end

.

A case begins the keyword case , followed by an integer constant,

followed by a colon and then a statement. A default case may be speci ed after all the other cases by using

the keyword default followed by a colon and then a statement.

You may use EBNF for this question

Explanation / Answer

Context Free Grammar for Switch statement
---------------------------------------------------
<start> ---à switch ( <expr> ) <stmt>
<stmt> ---à case <expr> : <stmt>
<stmt> = Statement
<expr> = Expression
Non-terminal symbols are <stmt> and <expr>
Terminal symbols are switch and case
The symbol <stmt> at the end of the first line is the production
<start> is the Start symbol

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