Parser refactoring

[kasperosterbye]

Currently the AST nodes (blocks) implement part of the parsing algorithm. One way to refactoring this would be to split the blocks into two objects:

• The AST blocks without support for parsing
• BlockBuilders that work together with the parser

Besides being a cleaner design, it will allow us to:

• Have multiple syntaxes for the same block - for example a paragraph and an inline syntax for raw
• Having AST blocks with no syntax - I have used SectionBlocks for some of my work
• Having the same type of AST blocks for paragraph and inline blocks

This is a large rewrite, and it is not critical.

[kasperosterbye]

I just wanted it to sit here for us to remember the idea

[kasperosterbye]

The github way of allowing backquotes in inline codeblocks like this ` one is to mark the codeblock with two back quotes: mark with `` and end with `` (to embed two backquotes you mark the codeblock with three backquotes etc). Just an other example of the need to separate the parsing and the AST blocks.

[kasperosterbye]

This is something I would like to do in the fall. It will make things nicer, and also be a chance to revisit the inline parser. But in particular, it will make it clearer which states of the block should be internal to the parser, and which is intrinsic AST nodes.