Implement signature declarations

This implements not everything, but the most common case: simple top-level
declarations for functions.

data/examples/declaration/data/gadt/multiline-out.hs

@@ -4,9 +4,7 @@
 data Foo a where
   -- | 'Foo' is wonderful.
   Foo
-    :: forall a b. ( Show a
-                   , Eq b -- foo
-                   )
+    :: forall a b. (Show a, Eq b) -- foo
     => -- bar
     a
     -> b

data/examples/declaration/type/arguments-out.hs

@@ -0,0 +1,14 @@
+{-# LANGUAGE RankNTypes #-}
+functionName
+  :: (C1, C2, C3, C4, C5)
+  => a
+  -> b
+  -> ( forall a. (C6, C7)
+     => LongDataTypeName
+     -> a
+     -> AnotherLongDataTypeName
+     -> b
+     -> c
+     )
+  -> (c -> d)
+  -> (a, b, c, d)

data/examples/declaration/type/arguments.hs

@@ -0,0 +1,16 @@
+{-# LANGUAGE RankNTypes #-}
+
+functionName
+  :: (C1, C2, C3, C4, C5)
+  => a
+  -> b
+  -> (forall a.
+        (C6, C7)
+     => LongDataTypeName
+     -> a
+     -> AnotherLongDataTypeName
+     -> b
+     -> c
+     )
+  -> (c -> d)
+  -> (a, b, c, d)

data/examples/declaration/type/context-multi-line-out.hs

@@ -0,0 +1,10 @@
+functionName
+  :: ( C1
+     , C2
+     , C3
+     )
+  => a
+  -> b
+  -> c
+  -> d
+  -> (a, b, c, d)

data/examples/declaration/type/context-multi-line.hs

@@ -0,0 +1,10 @@
+functionName
+  :: ( C1
+     , C2
+     , C3
+     )
+  => a
+  -> b
+  -> c
+  -> d
+  -> (a, b, c, d)

data/examples/declaration/type/context-single-line-out.hs

@@ -0,0 +1,7 @@
+functionName
+  :: (C1, C2, C3)
+  => a
+  -> b
+  -> c
+  -> d
+  -> (a, b, c, d)

data/examples/declaration/type/context-single-line.hs

@@ -0,0 +1,7 @@
+functionName
+  :: (C1, C2, C3)
+  => a
+  -> b
+  -> c
+  -> d
+  -> (a, b, c, d)

data/examples/declaration/type/infix-promoted-type-constructor-out.hs

@@ -0,0 +1,3 @@
+fun1 :: Def ('[Ref s (Stored Uint32), IBool] T.:-> IBool)
+
+fun2 :: Def ('[Ref s (Stored Uint32), IBool] :-> IBool)

data/examples/declaration/type/infix-promoted-type-constructor.hs

@@ -0,0 +1,2 @@
+fun1 :: Def ('[ Ref s (Stored Uint32), IBool] 'T.:-> IBool)
+fun2 :: Def ('[ Ref s (Stored Uint32), IBool] ':-> IBool)

data/examples/declaration/type/long-function-name-out.hs

@@ -0,0 +1,6 @@
+longFunctionName
+  :: a
+  -> b
+  -> c
+  -> d
+  -> (a, b, c, d)

data/examples/declaration/type/long-function-name.hs

@@ -0,0 +1,6 @@
+longFunctionName
+  :: a
+  -> b
+  -> c
+  -> d
+  -> (a, b, c, d)

data/examples/declaration/type/long-multiline-applications-out.hs

@@ -0,0 +1,15 @@
+functionName
+  :: (C1, C2, C3, C4, C5)
+  => a
+  -> b
+  -> ( LongDataTypeName
+         AnotherLongDataTypeName
+         AnotherLongDataTypeName2
+         AnotherLongDataTypeName3
+     -> a
+     -> AnotherLongDataTypeName4
+     -> b
+     -> c
+     )
+  -> (c -> d)
+  -> (a, b, c, d)

data/examples/declaration/type/long-multiline-applications.hs

@@ -0,0 +1,15 @@
+functionName
+  :: (C1, C2, C3, C4, C5)
+  => a
+  -> b
+  -> (  LongDataTypeName
+          AnotherLongDataTypeName
+          AnotherLongDataTypeName2
+          AnotherLongDataTypeName3
+     -> a
+     -> AnotherLongDataTypeName4
+     -> b
+     -> c
+     )
+  -> (c -> d)
+  -> (a, b, c, d)

ormolu.cabal

@@ -60,6 +60,7 @@ library
                     , Ormolu.Printer.Meat.Common
                     , Ormolu.Printer.Meat.Declaration
                     , Ormolu.Printer.Meat.Declaration.Data
+                    , Ormolu.Printer.Meat.Declaration.Signature
                     , Ormolu.Printer.Meat.Declaration.Type
                     , Ormolu.Printer.Meat.Declaration.TypeFamily
                     , Ormolu.Printer.Meat.ImportExport

src/Ormolu/Printer/Meat/Declaration.hs

@@ -11,12 +11,14 @@ where
 import GHC
 import Ormolu.Printer.Combinators
 import Ormolu.Printer.Meat.Declaration.Data
+import Ormolu.Printer.Meat.Declaration.Signature
 import Ormolu.Printer.Meat.Declaration.Type
 import Ormolu.Printer.Meat.Declaration.TypeFamily
 
 p_hsDecl :: HsDecl GhcPs -> R ()
 p_hsDecl = \case
   TyClD x -> p_tyClDecl x
+  SigD x -> p_sigDecl x
   _ -> error "this is not yet supported"
 
 p_tyClDecl :: TyClDecl GhcPs -> R ()

src/Ormolu/Printer/Meat/Declaration/Signature.hs

@@ -0,0 +1,30 @@
+{-# LANGUAGE LambdaCase        #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RecordWildCards   #-}
+
+-- | Type signature declarations.
+
+module Ormolu.Printer.Meat.Declaration.Signature
+  ( p_sigDecl )
+where
+
+import GHC
+import Ormolu.Printer.Combinators
+import Ormolu.Printer.Meat.Common
+import Ormolu.Printer.Meat.Type
+
+p_sigDecl :: Sig GhcPs -> R ()
+p_sigDecl = \case
+  TypeSig names hswc -> line (p_typeSig names hswc)
+  _ -> error "Ormolu.Printer.Meat.Declaration.Signature: unimplemented signatures"
+
+p_typeSig
+  :: [Located RdrName]
+  -> LHsSigWcType GhcPs
+  -> R ()
+p_typeSig names HsWC {..} = do
+  spaceSep (located' p_rdrName) names
+  breakpoint
+  inci $ do
+    txt ":: "
+    relaxComments $ located (hsib_body hswc_body) p_hsType

src/Ormolu/Printer/Meat/Type.hs

@@ -24,7 +24,7 @@ p_hsType = \case
     txt ". "
     locatedVia Nothing t p_hsType
   HsQualTy qs t -> do
-    locatedVia Nothing qs p_hsContext
+    located qs p_hsContext
     breakpoint
     txt "=> "
     locatedVia Nothing t p_hsType