start : program. program = declaration | declaration program . endOfExpr = ";" | EOL . declaration = link_declaration | global_declaration | record_declaration | procedure_declaration . link_declaration = "link" link_list . link_list = file_name | file_name "," link_list . file_name = identifier | string_literal . global_declaration = "global" identifier_list . identifier_list = identifier | identifier_list "," identifier . record_declaration = "record" identifier "(" field_list_opt ")" . field_list_opt = field_list | . field_list = field_name | field_list "," field_name . field_name = identifier . procedure_declaration = proc_header locals_opt initial_opt expression_sequence "end" . proc_header = "procedure" identifier "(" parameter_list_opt ")" endOfExpr . parameter_list_opt = parameter_list | . parameter_list = identifier | identifier "[" "]" | identifier "," parameter_list . locals_opt = locals | . locals = local_specification identifier_list | local_specification identifier_list endOfExpr locals . local_specification = "local" | "static" . initial_opt = "initial" expression endOfExpr | . expression_sequence = expression_opt | expression_sequence endOfExpr expression_opt . expression_opt = expression | . expression = "break" expression_opt | "create" expression | "return" expression_opt | "suspend" expression_opt suspend_do_clause_opt | "fail" | "next" | "case" expression "of" "{" case_list "}" | "if" expression "then" expression else_clause_opt | "repeat" expression | "while" expression while_do_clause_opt | "until" expression until_do_clause_opt | "every" expression every_do_clause_opt | expr1 . suspend_do_clause_opt = "do" expression | . while_do_clause_opt = "do" expression | . until_do_clause_opt = "do" expression | . every_do_clause_opt = "do" expression | . else_clause_opt = "else" expression | . case_list = case_clause | case_list endOfExpr case_clause . case_clause = expression ":" expression | "default" ":" expression . expr1= expr1 "&" expr2 | expr2 . expr2= expr2 "?" expr3 | expr3 . expr3= expr4 ":=" expr3 | expr4 ":=:" expr3 | expr4 "<-" expr3 | expr4 "<->" expr3 | expr4 op_asgn expr3 | expr4 . expr4= expr4 "to" expr5 | expr4 "to" expr5 "by" expr5 | expr5 . expr5= expr5 "|" expr6 | expr6 . expr6= expr6 "<" expr7 | expr6 "<=" expr7 | expr6 "=" expr7 | expr6 ">=" expr7 | expr6 ">" expr7 | expr6 "~=" expr7 | expr6 "<<" expr7 | expr6 "<<=" expr7 | expr6 "==" expr7 | expr6 ">>=" expr7 | expr6 ">>" expr7 | expr6 "~==" expr7 | expr6 "===" expr7 | expr6 "~===" expr7 | expr7 . expr7= expr7 "||" expr8 | expr7 "|||" expr8 | expr8 . expr8= expr8 "+" expr9 | expr8 "-" expr9 | expr8 "++" expr9 | expr8 "--" expr9 | expr9 . expr9= expr9 "*" expr10 | expr9 "/" expr10 | expr9 "%" expr10 | expr9 "**" expr10 | expr10 . expr10= expr11 "^" expr10 | expr11 . expr11= expr11 "\" expr12 | expr11 "@" expr12 | expr11 "!" expr12 | expr12 . expr12= "not" expr12 | "|" expr12 | "!" expr12 | "*" expr12 | "+" expr12 | "-" expr12 | "." expr12 | "/" expr12 | "\" expr12 | "=" expr12 | "?" expr12 | "~" expr12 | "@" expr12 | "^" expr12 | expr13 . expr13= "(" expression_list ")" | "{" expression_sequence "}" | "[" expression_list "]" | expr13 "." field_name | expr13 "(" expression_list ")" | expr13 "{" expression_list "}" | expr13 "[" subscript_list "]" | identifier | keyword | literal . expression_list = expression_opt | expression_list "," expression_opt . subscript_list = subscript | subscript_list "," subscript . subscript = expression | expression ":" expression | expression "+:" expression | expression "-:" expression . keyword = "&" identifier . literal = string_literal | integer_literal | real_literal | cset_literal .