Vendor odoc-parser

[jonludlam]

This PR vendors odoc-parser into the repo. This helps prevent the use of mdx in odoc's tests. In this I've vendored the latest release of odoc-parser, but once ocaml/odoc#973 is merged we'll want to adjust the script to point at the odoc repo rather than the odoc-parser repo.

[panglesd]

The update-odoc-parser.sh script will need quite a lot of modifications when upgrading the vendored odoc-parser, but it is still good to keep it!

[panglesd]

I'm not sure, what is this line for?

[jonludlam]

Which, the git add? I should mention that this script was modelled closely on (copied from!) dune's equilvalent scripts, e.g. https://github.com/ocaml/dune/blob/main/vendor/update-cmdliner.sh

[panglesd]

Yes, I was wondering why automatically adding those files to the git index... (I'm OK with it, I just wanted to know if there was a specific reason you knew for this)

[gpetiot]

I left comments to update vendor/update-odoc-parser.sh to make it point to the odoc repo since the parser has been merged back.
Btw would it be possible to use git submodules for all this?

[gpetiot]

Suggested change

	version=ebfd3b9489e44187da2c67d79a32b6fc1e92bda4
	version=5ac1ffc67ce1b96f5a990fa4902a157a5cdb42d0

[gpetiot]

Suggested change

	git clone https://github.com/ocaml-doc/odoc-parser.git
	git clone https://github.com/ocaml/odoc.git

[gpetiot]

Suggested change

	cp -v $SRC/src/*.{ml,mli,mll} odoc-parser/src
	cp -v $SRC/src/parser/*.{ml,mli,mll} odoc-parser/src

[gpetiot]

Suggested change

	cd odoc-parser
	cd odoc

[gpetiot]

Suggested change

	SRC=$TMP/odoc-parser
	SRC=$TMP/odoc

[panglesd]

to make it point to the odoc repo since the parser has been merged back.

More modification would be needed since the new AST has changed the code block node.

Moreover, one would want to use the new syntax for "output of code blocks". Indeed, it would fix a bug where an error in the execution leads to:

{[
  let f = 1 + "2"
]}```mdx-error
An expression of type int was expected, but got a string
```

which is not valid odoc code.

[jonludlam]

I think we should merge this as-is, release a version of mdx, then do the work to upgrade to the new parser API.

[trefis]

I agree with this plan.

[gpetiot]

Moreover, one would want to use the new syntax for "output of code blocks". Indeed, it would fix a bug where an error in the execution leads to:

{[
  let f = 1 + "2"
]}```mdx-error
An expression of type int was expected, but got a string

I had a look at it, did I miss something regarding the new syntax for the output of code blocks? this is not mentioned in the docs

[panglesd]

More info is available here: ocaml-doc/odoc-parser#17

I don't know if the new syntax is documented in doco master's branch, but it's normal that it is not in the doc for the released version!