1; ISO 10303-21:2002 2 3alphabet = reverse_solidus 'P' upper reverse_solidus . 4apostrophe = '''' . 5arbitrary = reverse_solidus 'X' reverse_solidus hex_one . 6binary = '"' ( '0' | '1' | '2' | '3' ) { hex } '"' . 7character = space | digit | lower | upper | special | reverse_solidus | apostrophe . 8complex_entity_instance = entity_instance_name '=' subsuper_record ';' . 9control_directive = page | alphabet | extended2 | extended4 | arbitrary . 10data_section = 'DATA' [ '(' parameter_list ')' ] ';' entity_instance_list 'ENDSEC;' . 11digit = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' . 12end_extended = reverse_solidus 'X0' reverse_solidus . 13entity_instance = simple_entity_instance | complex_entity_instance . 14entity_instance_list = { entity_instance } . 15entity_instance_name = '#' digit { digit } . 16enumeration = '.' upper { upper | digit } '.' . 17exchange_file = 'ISO-10303-21;' header_section data_section { data_section } 'END-ISO-10303-21;' . 18extended2 = reverse_solidus 'X2' reverse_solidus hex_two { hex_two } end_extended . 19extended4 = reverse_solidus 'X4' reverse_solidus hex_four { hex_four } end_extended . 20header_entity = keyword '(' [ parameter_list ] ')' ';' . 21header_entity_list = header_entity { header_entity } . 22header_section = 'HEADER;' header_entity header_entity header_entity [header_entity_list] 'ENDSEC;' . 23hex = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' | 'A' | 'B' | 'C' | 'D' | 'E' | 'F' . 24hex_four = hex_two hex_two . 25hex_one = hex hex . 26hex_two = hex_one hex_one . 27integer = [ sign ] digit { digit } . 28keyword = user_defined_keyword | standard_keyword . 29list = '(' [ parameter { ',' parameter } ] ')' . 30lower = 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'g' | 'h' | 'i' | 'j' | 'k' | 'l' | 'm' | 'n' | 'o' | 'p' | 'q' | 'r' | 's' | 't' | 'u' | 'v' | 'w' | 'x' | 'y' | 'z' . 31non_q_char = special | digit | space | lower | upper . 32omitted_parameter = '*' . 33page = reverse_solidus 'S' reverse_solidus character . 34parameter = typed_parameter | untyped_parameter | omitted_parameter . 35parameter_list = parameter { ',' parameter } . 36real = [ sign ] digit { digit } '.' { digit } [ 'E' [ sign ] digit { digit } ] . 37reverse_solidus = '\' . 38sign = '+' | '-' . 39simple_entity_instance = entity_instance_name '=' simple_record ';' . 40simple_record = keyword '(' [ parameter_list ] ')' . 41simple_record_list = simple_record { simple_record } . 42space = ' ' . 43special = '!' | '"' | '*' | '$' | '%' | '&' | '.' | '#' | '+' | ',' | '-' | '(' | ')' | '?' | '/' | ':' | ';' | '<' | '=' | '>' | '@' | '[' | ']' | '{' | '|' | '}' | '^' | '`' | '~' . 44standard_keyword = upper { upper | digit } . 45string = '''' { non_q_char | apostrophe apostrophe | reverse_solidus reverse_solidus | control_directive } '''' . 46subsuper_record = '(' simple_record_list ')' . 47typed_parameter = keyword '(' parameter ')' . 48untyped_parameter = '$' | integer | real | string | entity_instance_name | enumeration | binary | list . 49upper = 'A' | 'B' | 'C' | 'D' | 'E' | 'F' | 'G' | 'H' | 'I' | 'J' | 'K' | 'L' | 'M' | 'N' | 'O' | 'P' | 'Q' | 'R' | 'S' | 'T' | 'U' | 'V' | 'W' | 'X' | 'Y' | 'Z' | '_' . 50user_defined_keyword = '!' upper { upper | digit } . 51