paf31 / dovetail Goto Github PK

I'll collect notes here as I start to think about general purpose debugging tools for Dovetail-enabled DSLs.

• Arrays
• Records
• Booleans
• Strings
• Numbers
• Maybe

This code:

class X a where
  x :: a

instance X String where
 x = ""

results in error

  Inexhaustive pattern match

In context:
  dict
  = { "x": ⋯ }

when evaluating x, presumably because the representation of type class dictionaries is not actually meant to be a record.

• Generate externs along with environment for foreign imports
• Support foreign types

It would be great to be able to capture the current continuation, or a delimited continuation, or possibly even serialize a continuation. This would make it possible to use PureScript for scripting Haskell in some really interesting ways, but serializable continuations might be tricky since FFI functions would need to be defunctionalized somehow, which might mean using something like static pointers.

Building test suite 'dovetail-test' for dovetail-0.1.1.0..
[1 of 2] Compiling Main             ( test/Spec.hs, dist/build/dovetail-test/dovetail-test-tmp/Main.o )

test/Spec.hs:198:15: error: Not in scope: ‘goldenFile’
    |
198 |               goldenFile = "test-files" </> name </> "golden",
    |               ^^^^^^^^^^

test/Spec.hs:199:15: error: Not in scope: ‘actualFile’
    |
199 |               actualFile = Just ("test-files" </> name </> "actual"),
    |               ^^^^^^^^^^

test/Spec.hs:210:28: error:
    Not in scope: type constructor or class ‘GenericArbitrary’
    |
210 |     deriving Arbitrary via GenericArbitrary ExampleRecord1
    |                            ^^^^^^^^^^^^^^^^

GHC 8.10.7

Oddly I’ve wanted something like this for a while.

• External facing DSLs (like my jl) within Haskell
• For a “close enough to Haskell that you could embed it with TH”
• Using PureScript for server side dev instead of Haskell potentially
• Testing my client side code with a Haskell test suite - something I am currently doing with QuickJS
• Server-side rendering of client side code
• Exploring hot reloading

So thanks for sharing this, it opens up a lot of possibilities.

Hi, do you have a plan already for modelling Effect? The FFI doesn't mention it yet.

Perhaps you plan to add it to the FFI?

Or else, perhaps you might use a tagged approach where the Effect type is a tagged initial free-monad style thing and then it just returns constructors which a user of dovetail could interpret?

Thanks.

I assume you’ve been using this for a project, @paf31. What’s your experience been like so far? Trade offs? What was good, bad, or surprising?

I am still interested in exploring it for scripting. Just limited in time.

• Source spans
• Stack traces
• Environment