Rewrite the following BNF grammar using the form of EBNF described on the bottom

Question

Rewrite the following BNF grammar using the form of EBNF described on the bottom half of page 127 in Sebesta.

<import_decl> import <import_list> ;

<import_list> <package_list>

| <package_list> . *

<package_list> <identifier>

| <package_list> . <identifier>

<identifier> a | b | c

Make the resulting grammar as simple as possible, but keep all four of the original nonterminals, which will now be named ImportDecl, ImportList, PackageList, and Identifier. (Note: There are some typographical errors on page 127. See page 3-21 of the course notes for a better description of this form of EBNF.)

Explanation / Answer

<assign> -> import = <import_list>

<import_list> -> <package_list> {(+ | * ) } '.'

<package_list> -> <identifier> {(+ ) | <package_list>

<identifier> -> ( a | b | c )

The same grammer is shown ebnf in which the

<import_list> <package_list>

| <package_list> . * is converted to <import_list> -> <package_list> {(+ | * ) } '.'

and <identifier> a | b | c is converted to <identifier> -> ( a | b | c ) with parenthesis.

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