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Sorry about the other PR that got closed. Not sure what I did there.
This PR is a patch for an upcoming release of ppxlib where the internal AST is bumped from 4.14 to 5.2. Until that is merged and released, there is no reason to merge this PR.
To test these changes, you can use the following opam-based workflow. I've made releases of most of these patches to an opam-repository overlay.
The following describes the most notable changes to the AST.
Note: no update has been made of the
opam
file, butppxlib
will likely need a lower-bound before merging/releasing.Functions
Currently
In the parsetree currently, functions like:
Are represented roughly as
Functions like:
Are represented roughly as
Since 5.2
All of these functions now map to a single AST node
Pexp_function
(note, this is the same name as the old cases function). The first argument is a list of parameters meaning:Now looks like:
Pexp_function([x; y; z], _constraint, body)
And the
body
is where we can either have more expressions (Pfunction_body _
) or cases (Pfunction_cases _
). That means:Has an empty list of parameters:
Local Module Opens for Types
Another feature added in 5.2 was the ability to locally open modules in type definitions.
This has a
Ptyp_open (module_identifier, core_type)
AST node. Just like normal module opens this does create some syntactic ambiguity about where things come from inside the parentheses.