HTML/Markdown style grammar for ANTLR4

Question

I want to define a HTML/Markdown like grammar for an document that gets transformed to an AST. I\'m aware, that ANTLR4 is not the best tool for doing Markdown things but I\'m wa

Answer 1

The current solution looks like this lexer and grammar rules:

lexer grammar dnpMDAuslagernLexer;

/*@members {
    public static final int COMMENTS = 1;
}*/

NL
    : [\r\n]
    ;

SUBHEADLINE
    : '##' (~[\r\n])+? '##'
    ;

HEADLINE
    : '#' ('\\#'|~[\r\n])+? '#'
    ;

LEAD
    : '###' (~[\r\n])+? '###'
    ;

SUBHEADING
    : '####' (~[\r\n])+? '####'
    ;

CAPTION
    : '#####' (~[\r\n])+? '#####'
    ;

LISTING
    : '~~~~~' .+? '~~~~~'
    ;

ELEMENTPATH
    : '[[[[[' (~[\r\n])+? ']]]]]'
    ;

LABELREF
    : '{##' (~[\r\n])+? '##}'
    ;

LABEL
    : '{#' (~[\r\n])+? '#}'
    ;

ITALIC
    : '*' (~[\r\n])+? '*'
    ;

SINGLE_COMMENT
    : '//' (~[\r\n])+ -> channel(1)
    ;

MULTI_COMMENT
    : '/*' .*? '*/' -> channel(1)
    ;

STAR
    : '*'
    ;

BRACE_OPEN
    : '{'
    ;

TEXT
    : (~[\r\n*{])+
    ;

parser grammar dnpMDAuslagernParser;

options { tokenVocab=dnpMDAuslagernLexer; }

dnpMD
    : head body
    ;

head
    : subheadline headline lead
    ;

subheadline
    : SUBHEADLINE NL+
    ;

headline
    : HEADLINE NL+
    ;

lead
    : LEAD
    ;

subheading
    : SUBHEADING
    ;

caption
    : CAPTION
    ;

listing
    : LISTING (NL listingPath)? (NL label)? NL caption
    ;

image
    : caption (NL label)? (NL imagePath)?
    ;

listingPath
    : ELEMENTPATH
    ;

imagePath
    : ELEMENTPATH
    ;

labelRef
    : LABELREF
    ;

label
    : LABEL
    ;

italic
    : ITALIC
    ;

singleComment
    : SINGLE_COMMENT
    ;

multiComment
    : MULTI_COMMENT
    ;

paragraph
    : TEXT? italic TEXT?
    | TEXT? STAR TEXT?
    | TEXT? labelRef TEXT?
    | TEXT? BRACE_OPEN TEXT?
    | TEXT? LABEL TEXT?
    | ELEMENTPATH
    | TEXT
    ;

newlines
    : NL+
    ;

body
    : bodyElements+
    ;

bodyElements
    : singleComment
    | multiComment
    | paragraph
    | subheading
    | listing
    | image
    | newlines
    ;

This language is working fine and maybe someone can benefit from it.

Thanks to all who helped out! Fabian