refactor: add type candidates and template generators #1361
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This commit adds a new module and type, the TypeCandidate, which represents a potentially valid or invalid type. We use it as the input for both type validation routines and type binding generation. The type also allows us to unify the structure of sum types and product types in an xobj agnostic way, paving the way for future simplification of binding generation for type definitions. This commit also removes SumtypeCase.hs, since it's no longer needed.
This commit builds on the TypeCandidate data structure further by
providing "template generators" that work on candidates. Using
generators, templates for type functions ("methods") can be written
almost completely declaratively. Generators also remove some of the
typical boilerplate involved in creating templates from lists of tokens
and enable us to unify several of the generic and concrete templates for
types.
Generators can act on type candidates or their fields (for
field-specific functions). In general, this approach makes the
generation of type templates more structured. A type candidate now
contains all the information a generator needs to create appropriate
templates, thus it is a single and well-defined input for validation and
generation of user defined types.
This commit also updates the Deftype templates to use template
generators.
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Again, the nix build failure seems to stem from nix related set up and is not the result of a failed build or failing tests. |
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From reading your description of the PR, this sounds fabulous! I have yet to dig into the code, might take a few days to get through it. |
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Sounds good! Yeah the diff is pretty large. No functionality changes though, so hopefully the new code is easy enough to understand. Let me know if you have any questions! |
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@scolsen I've read through once now, It looks very good! I want to go over some parts a second time to understand them better before mergeing. Sorry for the review taking a while, last week was super hectic.
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No problem! Let me know if I can help at all. |
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Alright, I feel like I've got a pretty good overview now! It was a lovely read, really.
Lots of new types, which is great :D
I do worry a little about the abstraction tower "TemplateGenerator > TemplateCreator > Template"; it's not very intuitive. But it definitely does the job, and also brings some more structure to the process.
I have one request before we merge – could you run ./scripts/format.sh on the code?
Apart from that, this is awesome and more than ready for master. Let's kick off a celebratory release once it's in!
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@scolsen Alternatively, I can make a follow up PR where I run the formatter. Might actually be better, the diff from this merge commit will be neater. If that sounds good, I'll just merge as-is. |
Sorry for missing this--I was away! Thanks for applying the formatting! |
This PR adds two new modules that help with managing user defined types:
This PR also removed
SumtypeCasewhich is no longer needed after the introduction ofTypeCandidate. TypeCandidates haveTypeFieldswhich do the old job of sumtype cases (and similarly of XObj pairings on the struct/product side).