1; ISO 10303-21:1994 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 '=' [ scope ] subsuper_record ';' . 9control_directive = page | alphabet | extended2 | extended4 | arbitrary . 10data_section = 'DATA' ';' 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 { entity_instance } . 15entity_instance_name = '#' digit { digit } . 16enumeration = '.' upper { upper | digit } '.' . 17exchange_file = 'ISO-10303-21' ';' header_section data_section 'END-ISO-10303-21' ';' . 18export_list = '/' entity_instance_name { ',' entity_instance_name } '/' . 19extended2 = reverse_solidus 'X2' reverse_solidus hex_two { hex_two } end_extended . 20extended4 = reverse_solidus 'X4' reverse_solidus hex_four { hex_four } end_extended . 21header_entity = keyword '(' [ parameter_list ] ')' ';' . 22header_entity_list = header_entity { header_entity } . 23header_section = 'HEADER' ';' header_entity header_entity header_entity [ header_entity_list ] 'ENDSEC' ';' . 24hex = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' | 'A' | 'B' | 'C' | 'D' | 'E' | 'F' . 25hex_four = hex_two hex_two . 26hex_one = hex hex . 27hex_two = hex_one hex_one . 28integer = [ sign ] digit { digit } . 29keyword = user_defined_keyword | standard_keyword . 30list = '(' [ parameter { ',' parameter } ] ')' . 31lower = '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' . 32non_q_char = special | digit | space | lower | upper . 33omitted_parameter = '*' . 34page = reverse_solidus 'S' reverse_solidus character . 35parameter = typed_parameter | untyped_parameter | omitted_parameter . 36parameter_list = parameter { ',' parameter } . 37real = [ sign ] digit { digit } '.' { digit } [ 'E' [ sign ] digit { digit } ] . 38reverse_solidus = '\' . 39scope = '&' 'SCOPE' entity_instance_list 'ENDSCOPE' [ export_list ] . 40sign = '+' | '-' . 41simple_entity_instance = entity_instance_name '=' [ scope ] simple_record ';' . 42simple_record = keyword '(' [ parameter_list ] ')' . 43simple_record_list = simple_record { simple_record } . 44space = ' ' . 45special = '!' | '"' | '*' | '$' | '%' | '&' | '.' | '#' | '+' | ',' | '-' | '(' | ')' | '?' | '/' | ':' | ';' | '<' | '=' | '>' | '@' | '[' | ']' | '{' | '|' | '}' | '^' | '`' . 46standard_keyword = upper { upper | digit } . 47string = '''' { non_q_char | apostrophe apostrophe | reverse_solidus reverse_solidus | control_directive } '''' . 48subsuper_record = '(' simple_record_list ')' . 49typed_parameter = keyword '(' parameter ')' . 50untyped_parameter = '$' | integer | real | string | entity_instance_name | enumeration | binary | list . 51upper = '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' . 52user_defined_keyword = '!' upper { upper | digit } . 53