From 354ede1ea60a5bab3fcfd4d792c49c8161375f1a Mon Sep 17 00:00:00 2001
From: Paul Chiusano <paul.chiusano@gmail.com>
Date: Mon, 10 May 2021 20:43:03 -0500
Subject: [PATCH] Elide unit from `display` output

---
 .../src/Unison/CommandLine/DisplayValues.hs   | 19 ++++++++++++++++---
 parser-typechecker/src/Unison/TermPrinter.hs  |  6 ++++--
 .../transcripts-using-base/doc.output.md      |  2 --
 3 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/parser-typechecker/src/Unison/CommandLine/DisplayValues.hs b/parser-typechecker/src/Unison/CommandLine/DisplayValues.hs
index fc16d90f7..5e6cf59b5 100644
--- a/parser-typechecker/src/Unison/CommandLine/DisplayValues.hs
+++ b/parser-typechecker/src/Unison/CommandLine/DisplayValues.hs
@@ -41,7 +41,20 @@ displayTerm :: (Var v, Monad m)
            -> (Reference -> m (Maybe (DD.Decl v ())))
            -> Term v ()
            -> m Pretty
-displayTerm pped terms typeOf eval types = \case
+displayTerm = displayTerm' False
+
+type ElideUnit = Bool
+
+displayTerm' :: (Var v, Monad m)
+           => ElideUnit -- whether to elide printing of `()` from the end of the block
+           -> PPE.PrettyPrintEnvDecl
+           -> (Reference -> m (Maybe (Term v ())))
+           -> (Referent -> m (Maybe (Type v ())))
+           -> (Term v () -> m (Maybe (Term v ())))
+           -> (Reference -> m (Maybe (DD.Decl v ())))
+           -> Term v ()
+           -> m Pretty
+displayTerm' elideUnit pped terms typeOf eval types = \case
   tm@(Term.Apps' (Term.Constructor' typ _) _)
     | typ == DD.docRef             -> displayDoc pped terms typeOf eval types tm
     | typ == DD.doc2Ref            -> do
@@ -65,7 +78,7 @@ displayTerm pped terms typeOf eval types = \case
       P.wrap $ "Sadly, I don't know the error, but you can evaluate"
             <> "the above expression in a scratch file to see it."
       ]
-    src tm = TP.prettyBlock (PPE.suffixifiedPPE pped) tm
+    src tm = TP.prettyBlock elideUnit (PPE.suffixifiedPPE pped) tm
 
 -- assume this is given a
 -- Pretty.Annotated ann (Either SpecialForm ConsoleText)
@@ -144,7 +157,7 @@ displayPretty pped terms typeOf eval types tm = go tm
 
     DD.Doc2SpecialFormExampleBlock n (DD.Doc2Example vs body) ->
       -- todo: maybe do something with `vs` to indicate the variables are free
-      P.indentN 4 <$> displayTerm pped terms typeOf eval types ex
+      P.indentN 4 <$> displayTerm' True pped terms typeOf eval types ex
       where ex = Term.lam' (ABT.annotation body) (drop (fromIntegral n) vs) body
 
     -- Link (Either Link.Type Doc2.Term)
diff --git a/parser-typechecker/src/Unison/TermPrinter.hs b/parser-typechecker/src/Unison/TermPrinter.hs
index b93c3eab3..ab72ce783 100644
--- a/parser-typechecker/src/Unison/TermPrinter.hs
+++ b/parser-typechecker/src/Unison/TermPrinter.hs
@@ -50,8 +50,10 @@ import qualified Unison.ConstructorType as CT
 pretty :: Var v => PrettyPrintEnv -> Term v a -> Pretty ColorText
 pretty env = PP.syntaxToColor . pretty0 env emptyAc . printAnnotate env
 
-prettyBlock :: Var v => PrettyPrintEnv -> Term v a -> Pretty ColorText
-prettyBlock env = PP.syntaxToColor . pretty0 env emptyBlockAc . printAnnotate env
+prettyBlock :: Var v => Bool -> PrettyPrintEnv -> Term v a -> Pretty ColorText
+prettyBlock elideUnit env =
+  PP.syntaxToColor . pretty0 env (emptyBlockAc { elideUnit = elideUnit })
+                   . printAnnotate env
 
 pretty' :: Var v => Maybe Width -> PrettyPrintEnv -> Term v a -> ColorText
 pretty' (Just width) n t =
diff --git a/unison-src/transcripts-using-base/doc.output.md b/unison-src/transcripts-using-base/doc.output.md
index 6f977f756..0b20df466 100644
--- a/unison-src/transcripts-using-base/doc.output.md
+++ b/unison-src/transcripts-using-base/doc.output.md
@@ -287,7 +287,6 @@ and the rendered output using `display`:
         cube x =
           use Nat *
           x * x * x
-        ()
 
 .> view includingSource
 
@@ -625,7 +624,6 @@ Lastly, it's common to build longer documents including subdocuments via `{{ sub
           cube x =
             use Nat *
             x * x * x
-          ()
   
     # Including Unison source code