statement ::= labeled-stmt | expr-stmt | compound-stmt | decl-stmt | try-block | 
    if ( condition ) statement | if ( condition ) statement else statement | 
    switch ( condition ) statement | while ( condition ) statement | 
    do statement while ( expression ) | 
    for ( for-init-stmt [condition] ; [expression] ) statement | break ; | 
    continue ; | goto identifier ; | return [expression] ;
expr-stmt ::= [expression] ;
compound-stmt ::= { [statement-seq] }
statement-seq ::= statement | statement-seq
labeled-stmt ::= identifier : statement | case constant-expr : statement | 
    default : statement
decl-stmt ::= block-decl
for-init-stmt ::= expr-stmt | simple-decl
condition ::= expression | type-specifier-seq declarator = assignment-expr