Partial MD grammar test.

2026-08-05 23:28:45 +00:00 · 2021-02-13 19:57:59 +01:00
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+/* MetaDesk grammar with semantic annotations
+ *
+ * Each line represents a BNF-esque production of the form:
+ *      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, @leaf, @tag)
+ *   and miscellaneous semantics (@delimiter)
+ */
+
+file            : [@child set_list]
+set_list        : tagged_named_set [' ' @sibling set_list]
+tagged_named_set: { [tag_list] set }
+tag_list        : @tag tag ' ' [tag_list]
+tag             : '@' identifier        // TODO(mal): tag parameters
+set             : @leaf leaf | '{' [@child set_list] '}'
+leaf            : identifier | integer_literal | char_literal | string_literal  // TODO(mal): Also symbol_label
+identifier      : alpha [alphanumeric]  // TODO(mal): I think we should allow leading underscores
+alphanumeric    : alpha [alphanumeric] | digit [alphanumeric] | '_' [alphanumeric]
+
+integer_literal : { ['-'] natural_literal }
+natural_literal : digit [natural_literal]
+
+char_literal                    : @delimiter '\'' [char_literal_items] @delimiter '\''
+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 | space
+symbol_no_backslash_no_quotes   : symbol_no_backslash_no_quotes_1 | symbol_no_backslash_no_quotes_2
+symbol_no_backslash_no_quotes_1 : '!'|'#'|'$'|'%'|'&'|'('|')'|'*'|'+'|','|'-'|'.'|'/'|':'|';'
+symbol_no_backslash_no_quotes_2 : '<'|'='|'>'|'?'|'@'|'['|']'|'^'|'_'|'`'|'{'|'|'|'}'|'~'
+
+string_literal                  : @delimiter '"' [string_literal_items] @delimiter '"'
+string_literal_items            : string_literal_item [string_literal_items]
+string_literal_item             : ascii_no_backslash_no_quotes | '\'' | '\\' ascii
+
+digit           : '0'|'1'|'2'|'3'|'4'|'5'|'6'|'7'|'8'|'9'
+alpha           : lowercase | uppercase
+lowercase       : 'a'|'b'|'c'|'d'|'e'|'f'|'g'|'h'|'i'|'j'|'k'|'l'|'m'|'n'|'o'|'p'|'q'|'r'|'s'|'t'|'u'|'v'|'w'|'z'|'y'|'z'
+uppercase       : 'A'|'B'|'C'|'D'|'E'|'F'|'G'|'H'|'I'|'J'|'K'|'L'|'M'|'N'|'O'|'P'|'Q'|'R'|'S'|'T'|'U'|'V'|'W'|'Z'|'Y'|'Z'
+space           : ' '
+
+symbol_label    : '~'|'!'|'%'|'^'|'&'|'*'|'+'|'-'|'/'|'|'|'<'|'>'|'$'|'='|'.'|'?'|'_'|'\\'
+
+/*
+
+symbol_no_quote : symbol_label | symbol_colon | symbol_group
+
+symbol          : symbol_label | symbol_colon | symbol_group
+
+symbol_group    : symbol_open | symbol_close
+symbol_open     : '(' | '[' | '{'
+symbol_close    : ')' | ']' | '}' 
+
+escaped_char    : '\\' '\\' | '\\' '\'' | '\\' '\"'
+symbol_colon    : ':'
+
+*/
+
+
+/*
+    // NOTE(mal): I think this one should work too, but MD only delimits top level constructs with newlines
+    file            : [@child set_list]
+    set_list        : set [',' @sibling set_list]
+    set             : @leaf element | '{' [@child set_list] '}'
+    element         : 'A'
+
+    // NOTE(mal): This is the simples grammar that works
+    file            : [@child set_list]
+    set_list        : set ['\n' @sibling set_list]
+    set             : @leaf element | '{' [@child set_list] '}'
+    element         : 'A'
+*/
+