make `osp :: QuasiQuoter` valid as a pattern

lawbel commented 7 months ago

Resolves issue #205

Notes:

Alternative to the quote [p|...|] is something like
```
viewP (appE (varE '(==)) (lift osp')) (conP 'True [])
```
Although this may then need CPP to adjust for conP gaining an extra argument in template-haskell v2.18.0.0. Not sure which GHC version this changed in, but it's due to the ability to bind a type parameter with a constructor like
```
foo :: Maybe a -> String
foo (Just @a x) = "just"
```
Given that, I thought the quote would be clearer. I'm assuming it should be easier to maintain as well, as it should avoid the need to update with any TH changes?
TemplateHaskellQuotes and ViewPatterns extensions both go back to GHC v6.x which should be plenty for back-compat?
Any other changes that should be made? Add some suitable tests?
Should we change the other QuasiQuoters as well? Make similar changes to osstr and pstr?

Bodigrim commented 7 months ago

I think filepath should define just

osp :: QuasiQuoter
osp = OS.osstr

pstr :: QuasiQuoter
pstr = OS.osstr

while the actual quasiquoter to be improved in https://github.com/haskell/os-string.

hasufell commented 7 months ago

I think filepath should define just
osp :: QuasiQuoter
osp = OS.osstr

pstr :: QuasiQuoter
pstr = OS.osstr
while the actual quasiquoter to be improved in https://github.com/haskell/os-string.

We run isValid at compile time here, which we don't in the osstr quasiquoters.

hasufell commented 7 months ago

@lawbel we probably want this patch for os-string as well

lawbel commented 7 months ago

@hasufell sorry I wasn't able to look at this over the weekend. I see you've done a PR for os-string as well, so I guess this is all done then? I appreciate the help in getting this over the line :smile:

haskell / filepath

make `osp :: QuasiQuoter` valid as a pattern #210