metadesk/tests/grammar.md

/* MetaDesk grammar with semantic annotations *

• Each line represents a BNF-esque production:

•  symbol : rule_1 | ... | rule_n
  

• • Pipe signs indicate mutually exclusive alternatives
• • Square quotes denote optional rules
• • Character literals are terminal productions
• • Tags indicate which way the productions attach to the generated tree (@child, @sibling, @tag)
• and miscellaneous semantics (@fill, @markup) */

//// Arbitrarily deep tree, possibly empty // file : [@child set] // set : '{' [@child set] '}' | set [' ' @sibling set]

//// Labeled leaves // file : [@child set] // set : @fill 'A' | '{' [@child set] '}' | set [' ' @sibling set]

//// Labels also on internal nodes ('iset' is an implicitly separated set) // file : [@child set] // set : @fill 'A' [':' @child iset '\n'] | [@fill 'A' ':'] scoped_set | set [' ' @sibling set] // iset : @fill 'A' [iset_tail] // iset_tail : ':' @child iset | ' ' @sibling iset | ':' scoped_set | ' ' @sibling scoped_set // scoped_set : '{' [@child set] '}'

//// Tags // file : [@child set] // set : {[tag_list] untagged_set} // iset : {[tag_list] untagged_iset} // tag_list : '@' @tag tag ' ' [tag_list] // tag : @fill 'T'['(' [@child set] ')'] // untagged_set : @fill 'A' [':' @child iset '\n'] | [@fill 'A' ':'] scoped_set | set [' ' @sibling set] // untagged_iset : @fill 'A' [iset_tail] // iset_tail : ':' @child iset | ' ' @sibling iset | ':' scoped_set | ' ' @sibling scoped_set // scoped_set : '{' [@child set] '}'

//// Alternative scope markers // file : [@child set] // set : {[tag_list] untagged_set} // iset : {[tag_list] untagged_iset} // tag_list : '@' @tag tag ' ' [tag_list] // tag : @fill 'T'['(' [@child set] ')'] // untagged_set : @fill 'A' [':' @child iset '\n'] | [@fill 'A' ':'] scoped_set | set [' ' @sibling set] // untagged_iset : @fill 'A' [iset_tail] // iset_tail : ':' @child iset | ' ' @sibling iset | ':' scoped_set | ' ' @sibling scoped_set // scoped_set : '{' [@child set] '}' | scope_beg [@child set] scope_end // scope_beg : '(' | '[' // scope_end : ')' | ']'

//// Identifiers // file : [@child set] // set : {[tag_list] untagged_set} // iset : {[tag_list] untagged_iset} // tag_list : '@' @tag tag ' ' [tag_list] // tag : @fill id['(' [@child set] ')'] // untagged_set : @fill 'A' [':' @child iset '\n'] | [@fill 'A' ':'] scoped_set | set [' ' @sibling set] // untagged_iset : @fill 'A' [iset_tail] // iset_tail : ':' @child iset | ' ' @sibling iset | ':' scoped_set | ' ' @sibling scoped_set // scoped_set : '{' [@child set] '}' | scope_beg [@child set] scope_end // scope_beg : '(' | '[' // scope_end : ')' | ']' // id : alpha [alphanumeric] // alphanumeric : alpha [alphanumeric] | digit [alphanumeric] | '_' [alphanumeric] // alpha : lowercase | uppercase // lowercase : 'a'|'b'|'c'|'d'|'e'|'f'|'g'|'h'|'i'|'j'|'k'|'l'|'m'|'n'|'o'|'p'|'q'|'r'|'s'|'t'|'u'|'v'|'w'|'z'|'y'|'z' // uppercase : 'A'|'B'|'C'|'D'|'E'|'F'|'G'|'H'|'I'|'J'|'K'|'L'|'M'|'N'|'O'|'P'|'Q'|'R'|'S'|'T'|'U'|'V'|'W'|'Z'|'Y'|'Z' // digit : '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9'

//// General labels file : [@child set] set : {[tag_list] untagged_set} iset : {[tag_list] untagged_iset} tag_list : '@' @tag tag ' ' [tag_list] tag : @fill id['(' [@child set] ')'] untagged_set : @fill label [':' @child iset '\n'] | [@fill label ':'] scoped_set | set [' ' @sibling set] untagged_iset : @fill label [iset_tail] iset_tail : ':' @child iset | ' ' @sibling iset | ':' scoped_set | ' ' @sibling scoped_set scoped_set : '{' [@child set] '}' | scope_beg [@child set] scope_end scope_beg : '(' | '[' scope_end : ')' | ']' id : alpha [alphanumeric] | '' [alphanumeric] alphanumeric : alpha [alphanumeric] | digit [alphanumeric] | '' [alphanumeric] alpha : lowercase | uppercase lowercase : 'a'|'b'|'c'|'d'|'e'|'f'|'g'|'h'|'i'|'j'|'k'|'l'|'m'|'n'|'o'|'p'|'q'|'r'|'s'|'t'|'u'|'v'|'w'|'z'|'y'|'z' uppercase : 'A'|'B'|'C'|'D'|'E'|'F'|'G'|'H'|'I'|'J'|'K'|'L'|'M'|'N'|'O'|'P'|'Q'|'R'|'S'|'T'|'U'|'V'|'W'|'Z'|'Y'|'Z' digit : '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9' label : id | integer_literal | char_literal | string_literal | symbol_label integer_literal : { ['-'] natural_literal } natural_literal : digit [natural_literal] char_literal : @markup ''' [char_literal_items] @markup ''' char_literal_items : char_literal_item [char_literal_items] char_literal_item : ascii_no_backslash_no_quotes | '"' | '\' ascii ascii : ascii_no_backslash_no_quotes | ''' | '"' | '' | '\\' ascii_no_backslash_no_quotes : digit | alpha | symbol_no_backslash_no_quotes | ' ' symbol_no_backslash_no_quotes : symbol_no_backslash_no_quotes_1 | symbol_no_backslash_no_quotes_2 symbol_no_backslash_no_quotes_1 : '!'|'#'|'$'|'%'|'&'|'('|')'|'*'|'+'|','|'-'|'.'|'/'|':' symbol_no_backslash_no_quotes_2 : ';'|'<'|'='|'>'|'?'|'@'|'['|']'|'^'|'_'|'{'|'|'|'}'|'~' string_literal : @markup '"' [string_literal_items] @markup '"' | @markup '' [string_literal_items] @markup '`' string_literal_items : string_literal_item [string_literal_items] string_literal_item : ascii_no_backslash_no_quotes | ''' | '\' ascii symbol_label : '~'|'!'|'%'|'^'|'&'|'*'|'+'|'-'|'/'|'|'|'<'|'>'|'$'|'='|'.'|'?'|'$'