Span vs Link syntax in LR(1) parsers?
syntax
We need to add support for the following two syntaxes, where {ATTR} is one of {language}, {=raw-format}, {#id .class key=value}, {ATTR} is optional:
- Fenced spans:
[span text]{ATTR} - Links:
[link text](./destination title){ATTR}
Unless I’m missing something fairly fundamental, this cannot be readily parsed using LR(1) parsers, because the one-token lookahead at [ can’t tell if this is going to be a link or a span…
(In contrast, images ![]() vs links are easy, because ! sends the parser into the “image” part of the state table.)
The hack we’re going to use in the parser is to change the inline link syntax to make the link destination optional. Then, at the time of interpreting the parse tree, links without destinations are considered spans.
That appears to work.