标记为Xtext DSL

Question

我想将Markdown构建为Xtext。但是解析像# Introduction这样的标题似乎很棘手，因为它没有明确的结束符号。有什么办法表达这一点吗？还是一般情况下(也不仅仅是Xtext限制)不可能？

这是我的Xtext：

grammar markdown.Markdown with org.eclipse.xtext.common.Terminals

generate markdown "http://www.Markdown.markdown"

Model:
  entities+=Entity*;

Entity:
  Section | Subsection | Paragraph
;

Section:
  '#'
    content+=TextPart
  '::'
;

Subsection:
  '##'
    content+=TextPart
  '::'
;

Paragraph:
  content+=TextPart
;

TextPart:
  text=Text
;

Text:
        (ID | WS | SINGLE_NL | MULTI_NL | ANY_OTHER | '\\[' | '\\]' | ',' | "-" | '\\:' | '\\%' | '\\#' | '\\##' )+;


terminal ID:
        ('a'..'z' | 'A'..'Z' | '_') ('a'..'z' | 'A'..'Z' | '_' | '0'..'9')*;

terminal SL_COMMENT:
        '%%' !('\n' | '\r')* ('\r'? '\n');

terminal MULTI_NL:
        '\r'? '\n' (/*(' ' | '\t')**/ '\r'? '\n')+;

terminal SINGLE_NL:
        '\r'? '\n';

terminal WS:
        ' ' | '\t';

terminal ANY_OTHER:
        .;

终端来自Xdoc。有了这种语法规则，这是可能的：

# Introduction ::

Lorem ipsum.

## Other chapter ::

Lorem ipsum.

但我喜欢这样的降价：

# Introduction

Lorem ipsum.

## Other chapter

Lorem ipsum.

因此，我们需要\n而不是::作为结束。但这有可能吗？此外，antlr生成由终端规则引起的警告。但是在构建Xdoc.xtext时不会出现这种警告。我的错是什么？

warning(200): ../markdown/src-gen/markdown/parser/antlr/internal/InternalMarkdown.g:436:1: Decision can match input such as "'-'" using multiple alternatives: 9, 14
As a result, alternative(s) 14 were disabled for that input
warning(200): ../markdown/src-gen/markdown/parser/antlr/internal/InternalMarkdown.g:436:1: Decision can match input such as "'\\['" using multiple alternatives: 6, 14
As a result, alternative(s) 14 were disabled for that input
...

Answer 1

用Xtext基语言定义的单行注释终端非常类似：

terminal SL_COMMENT: '//' !('\n'|'\r')* ('\r'? '\n')?;

其基本思想是:符号可以包含任何不是行字符末尾的字符。