type-level-show 0.1.0 → 0.1.1

raw patch · 3 files changed

+58/−1 lines, 3 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• CHANGELOG.md +3/−0
• src/TypeLevelShow/Doc.hs +53/−0
• type-level-show.cabal +2/−1

@@ -1,3 +1,6 @@+## 0.1.1 (2024-05-16)+* add `Doc` type for `ErrorMessage`-like errors, except term level also+ ## 0.1.0 (2024-05-07) Initial release. 

@@ -0,0 +1,53 @@+{-# LANGUAGE AllowAmbiguousTypes #-} -- for reifying++module TypeLevelShow.Doc where++import GHC.TypeLits qualified as TE -- TE = TypeError+import GHC.TypeLits ( Symbol, KnownSymbol, symbolVal' )+import GHC.Exts ( proxy# )++-- | Simple pretty document ADT.+--+-- Designed to work on both type level (as a limited 'TE.ErrorMessage') and term+-- level (as a boring ADT).+--+-- Note that 'TE.ShowType' is magical (see+-- @compiler/GHC/Core/Type.hs#L1309@), so we need to remove it for term level.+--+-- singletons-base defines a version of this, but retains the 'TE.ShowType'+-- constructor and is in the singletons ecosystem.+data Doc s+  = Text s+  -- ^ plain ol' text+  | Doc s :<>: Doc s+  -- ^ append docs next to each other+  | Doc s :$$: Doc s+  -- ^ stack docs on top of each other (newline)+    deriving stock Show++-- | Promoted 'Doc'.+type PDoc = Doc Symbol++-- | Render a 'PDoc' as an 'ErrorMessage', for type-level error messages.+--+-- 'PDoc' is a subset of 'ErrorMessage', so this is very boring.+type RenderDoc :: PDoc -> TE.ErrorMessage+type family RenderDoc doc where+    RenderDoc (Text s)   = TE.Text s+    RenderDoc (l :<>: r) = RenderDoc l TE.:<>: RenderDoc r+    RenderDoc (l :$$: r) = RenderDoc l TE.:$$: RenderDoc r++-- | Reify a promoted 'Doc' to the corresponding term-level one.+class ReifyDoc (doc :: PDoc) where+    -- TODO do we want to do IsString directly in here? will it guarantee better+    --      performance, rather than mapping afterwards? hard to say+    reifyDoc :: Doc String++instance KnownSymbol s => ReifyDoc (Text s) where+    reifyDoc = Text $ symbolVal' (proxy# @s)++instance (ReifyDoc l, ReifyDoc r) => ReifyDoc (l :<>: r) where+    reifyDoc = reifyDoc @l :<>: reifyDoc @r++instance (ReifyDoc l, ReifyDoc r) => ReifyDoc (l :$$: r) where+    reifyDoc = reifyDoc @l :$$: reifyDoc @r

@@ -5,7 +5,7 @@ -- see: https://github.com/sol/hpack  name:           type-level-show-version:        0.1.0+version:        0.1.1 synopsis:       Utilities for writing Show-like type families description:    Please see README.md. category:       Types, Data@@ -31,6 +31,7 @@  library   exposed-modules:+      TypeLevelShow.Doc       TypeLevelShow.Natural       TypeLevelShow.Utils   other-modules: