From 3c339160346a634a03e622d97676bd7add36ae82 Mon Sep 17 00:00:00 2001
From: janmasrovira <janmasrovira@gmail.com>
Date: Wed, 1 Feb 2023 19:22:43 +0100
Subject: [PATCH] Remove braces from let expressions (#1790)

---
 src/Juvix/Compiler/Abstract/Pretty/Base.hs    |  4 +-
 src/Juvix/Compiler/Concrete/Pretty/Base.hs    |  6 +-
 .../Concrete/Translation/FromSource.hs        |  2 +-
 src/Juvix/Compiler/Internal/Pretty/Base.hs    |  4 +-
 src/Juvix/Data/CodeAnn.hs                     |  5 +-
 tests/Compilation/positive/test010.juvix      | 10 +--
 tests/Compilation/positive/test015.juvix      |  2 +-
 tests/Compilation/positive/test024.juvix      | 10 +--
 tests/Compilation/positive/test026.juvix      |  2 +-
 tests/Compilation/positive/test032.juvix      |  2 +-
 tests/Compilation/positive/test034.juvix      |  8 +-
 tests/Compilation/positive/test037.juvix      |  6 +-
 tests/negative/LetMissingClause.juvix         |  4 +-
 tests/positive/SignatureWithBody.juvix        |  4 +-
 tests/positive/StdlibList/Data/List.juvix     | 84 +++++++++----------
 tests/smoke/Commands/repl.smoke.yaml          |  2 +-
 16 files changed, 78 insertions(+), 77 deletions(-)

diff --git a/src/Juvix/Compiler/Abstract/Pretty/Base.hs b/src/Juvix/Compiler/Abstract/Pretty/Base.hs
index 49407839a..f6d9a1f95 100644
--- a/src/Juvix/Compiler/Abstract/Pretty/Base.hs
+++ b/src/Juvix/Compiler/Abstract/Pretty/Base.hs
@@ -118,7 +118,7 @@ ppPipeBlock :: (PrettyCode a, Members '[Reader Options] r, Traversable t) => t a
 ppPipeBlock items = vsep <$> mapM (fmap (kwPipe <+>) . ppCode) items
 
 ppBlock :: (PrettyCode a, Members '[Reader Options] r, Traversable t) => t a -> Sem r (Doc Ann)
-ppBlock items = bracesIndent . vsep . toList <$> mapM (fmap endSemicolon . ppCode) items
+ppBlock items = vsep . toList <$> mapM (fmap endSemicolon . ppCode) items
 
 instance PrettyCode ConstructorApp where
   ppCode (ConstructorApp ctr args) = do
@@ -172,7 +172,7 @@ instance PrettyCode LetClause where
 
 instance PrettyCode Let where
   ppCode l = do
-    letClauses' <- ppBlock (l ^. letClauses)
+    letClauses' <- blockIndent <$> ppBlock (l ^. letClauses)
     letExpression' <- ppCode (l ^. letExpression)
     return $ kwLet <+> letClauses' <+> kwIn <+> letExpression'
 
diff --git a/src/Juvix/Compiler/Concrete/Pretty/Base.hs b/src/Juvix/Compiler/Concrete/Pretty/Base.hs
index e95d4e276..cc65270df 100644
--- a/src/Juvix/Compiler/Concrete/Pretty/Base.hs
+++ b/src/Juvix/Compiler/Concrete/Pretty/Base.hs
@@ -144,7 +144,7 @@ instance PrettyCode Backend where
 instance (SingI s) => PrettyCode (Compile s) where
   ppCode Compile {..} = do
     compileName' <- ppSymbol _compileName
-    compileBackendItems' <- ppBlock _compileBackendItems
+    compileBackendItems' <- bracesIndent <$> ppBlock _compileBackendItems
     return $ kwCompile <+> compileName' <+> compileBackendItems'
 
 instance PrettyCode ForeignBlock where
@@ -478,7 +478,7 @@ instance PrettyCode Universe where
 
 instance (SingI s) => PrettyCode (LetBlock s) where
   ppCode LetBlock {..} = do
-    letClauses' <- ppBlock _letClauses
+    letClauses' <- blockIndent <$> ppBlock _letClauses
     letExpression' <- ppExpression _letExpression
     return $ kwLet <+> letClauses' <+> kwIn <+> letExpression'
 
@@ -488,7 +488,7 @@ instance (SingI s) => PrettyCode (LetClause s) where
     LetFunClause cl -> ppCode cl
 
 ppBlock :: (PrettyCode a, Members '[Reader Options] r, Traversable t) => t a -> Sem r (Doc Ann)
-ppBlock items = bracesIndent . vsep <$> mapM (fmap endSemicolon . ppCode) items
+ppBlock items = vsep <$> mapM (fmap endSemicolon . ppCode) items
 
 ppPipeBlock :: (PrettyCode a, Members '[Reader Options] r, Traversable t) => t a -> Sem r (Doc Ann)
 ppPipeBlock items = vsep <$> mapM (fmap (kwPipe <+>) . ppCode) items
diff --git a/src/Juvix/Compiler/Concrete/Translation/FromSource.hs b/src/Juvix/Compiler/Concrete/Translation/FromSource.hs
index b7e3cad2f..5d92f643c 100644
--- a/src/Juvix/Compiler/Concrete/Translation/FromSource.hs
+++ b/src/Juvix/Compiler/Concrete/Translation/FromSource.hs
@@ -412,7 +412,7 @@ letClause = either LetTypeSig LetFunClause <$> auxTypeSigFunClause
 letBlock :: (Members '[InfoTableBuilder, JudocStash, NameIdGen] r) => ParsecS r (LetBlock 'Parsed)
 letBlock = do
   _letKw <- kw kwLet
-  _letClauses <- braces (P.sepEndBy1 letClause (kw kwSemicolon))
+  _letClauses <- P.sepEndBy1 letClause (kw kwSemicolon)
   kw kwIn
   _letExpression <- parseExpressionAtoms
   return LetBlock {..}
diff --git a/src/Juvix/Compiler/Internal/Pretty/Base.hs b/src/Juvix/Compiler/Internal/Pretty/Base.hs
index 83829e902..4c4743d13 100644
--- a/src/Juvix/Compiler/Internal/Pretty/Base.hs
+++ b/src/Juvix/Compiler/Internal/Pretty/Base.hs
@@ -74,7 +74,7 @@ instance PrettyCode Expression where
 
 instance PrettyCode Let where
   ppCode l = do
-    letClauses' <- ppBlock (l ^. letClauses)
+    letClauses' <- blockIndent <$> ppBlock (l ^. letClauses)
     letExpression' <- ppCode (l ^. letExpression)
     return $ kwLet <+> letClauses' <+> kwIn <+> letExpression'
 
@@ -135,7 +135,7 @@ ppBlock ::
   (PrettyCode a, Members '[Reader Options] r, Traversable t) =>
   t a ->
   Sem r (Doc Ann)
-ppBlock items = bracesIndent . vsep . toList <$> mapM ppCode items
+ppBlock items = vsep . toList <$> mapM ppCode items
 
 instance PrettyCode InductiveParameter where
   ppCode (InductiveParameter v) = do
diff --git a/src/Juvix/Data/CodeAnn.hs b/src/Juvix/Data/CodeAnn.hs
index fa593e08f..15e75d417 100644
--- a/src/Juvix/Data/CodeAnn.hs
+++ b/src/Juvix/Data/CodeAnn.hs
@@ -258,4 +258,7 @@ ppStringLit = annotate AnnLiteralString . doubleQuotes . escaped
     escaped = mconcatMap (pretty . showChar) . unpack
 
 bracesIndent :: Doc Ann -> Doc Ann
-bracesIndent d = braces (line <> indent' d <> line)
+bracesIndent = braces . blockIndent
+
+blockIndent :: Doc Ann -> Doc Ann
+blockIndent d = line <> indent' d <> line
diff --git a/tests/Compilation/positive/test010.juvix b/tests/Compilation/positive/test010.juvix
index fa44823a3..22d0f1eba 100644
--- a/tests/Compilation/positive/test010.juvix
+++ b/tests/Compilation/positive/test010.juvix
@@ -5,11 +5,11 @@ open import Stdlib.Prelude;
 
 main : IO;
 main :=
-    let { x : Nat; x := 1 } in
-    let { x1 : Nat; x1 := x + let { x2 : Nat; x2 := 2 } in x2 } in
-    let { x3 : Nat; x3 := x1 * x1 } in
-    let { y : Nat; y := x3 + 2 } in
-    let { z : Nat; z := x3 + y } in
+    let x : Nat; x := 1 in
+    let x1 : Nat; x1 := x + let x2 : Nat; x2 := 2 in x2 in
+    let x3 : Nat; x3 := x1 * x1 in
+    let y : Nat; y := x3 + 2 in
+    let z : Nat; z := x3 + y in
     printNatLn (x + y + z);
 
 end;
diff --git a/tests/Compilation/positive/test015.juvix b/tests/Compilation/positive/test015.juvix
index 5cf5698c3..d54c207e5 100644
--- a/tests/Compilation/positive/test015.juvix
+++ b/tests/Compilation/positive/test015.juvix
@@ -7,7 +7,7 @@ open import Stdlib.Data.Nat.Ord;
 terminating
 f : Nat → Nat → Nat;
 f x :=
-    let {g : Nat → Nat; g y := x + y} in
+    let g : Nat → Nat; g y := x + y in
     if (x == 0)
        (f 10)
        (if (x < 10)
diff --git a/tests/Compilation/positive/test024.juvix b/tests/Compilation/positive/test024.juvix
index c8c698a38..bc4998fa4 100644
--- a/tests/Compilation/positive/test024.juvix
+++ b/tests/Compilation/positive/test024.juvix
@@ -16,12 +16,12 @@ terminating
 f : Tree → Nat;
 f leaf := 1;
 f (node l r) :=
-  let {l : Tree; l := g l} in
-  let {r : Tree; r := g r} in
-  let {terminating a : Nat; a := λ{leaf := 1 | (node l r) := f l + f r} l} in
-  let {terminating b : Nat;
+  let l : Tree; l := g l in
+  let r : Tree; r := g r in
+  let terminating a : Nat; a := λ {leaf := 1 | (node l r) := f l + f r} l in
+  let terminating b : Nat;
        b := λ {(node l r) := f l + f r
-                | _ := 2} r} in
+                | _ := 2} r in
   a * b;
 
 isNode : Tree → Bool;
diff --git a/tests/Compilation/positive/test026.juvix b/tests/Compilation/positive/test026.juvix
index 11f782e07..efba13935 100644
--- a/tests/Compilation/positive/test026.juvix
+++ b/tests/Compilation/positive/test026.juvix
@@ -16,7 +16,7 @@ front q := head (qfst q);
 
 pop_front : {A : Type} → Queue A → Queue A;
 pop_front {A} q :=
-  let {q' : Queue A; q' := queue (tail (qfst q)) (qsnd q)} in
+  let q' : Queue A; q' := queue (tail (qfst q)) (qsnd q) in
   case (qfst q') λ{
     nil := queue (reverse (qsnd q')) nil
     | _ := q'
diff --git a/tests/Compilation/positive/test032.juvix b/tests/Compilation/positive/test032.juvix
index 4a28157dc..404fa009f 100644
--- a/tests/Compilation/positive/test032.juvix
+++ b/tests/Compilation/positive/test032.juvix
@@ -20,7 +20,7 @@ merge' xs@(x :: xs') ys@(y :: ys') := if (x <= y) (x :: merge' xs' ys) (y :: mer
 terminating
 sort : List Nat → List Nat;
 sort xs :=
-  let {n : Nat; n := length xs} in
+  let n : Nat; n := length xs in
   if (n <= 1)
     xs
     (case (split (div n 2) xs) λ{
diff --git a/tests/Compilation/positive/test034.juvix b/tests/Compilation/positive/test034.juvix
index b9e1e3755..8667e08bd 100644
--- a/tests/Compilation/positive/test034.juvix
+++ b/tests/Compilation/positive/test034.juvix
@@ -4,16 +4,16 @@ module test034;
   open import Stdlib.Data.Nat.Ord;
 
   sum : Nat → Nat;
-  sum := let {
+  sum := let
       sum' : Nat → Nat;
       sum' := λ {
           zero := zero
           | (suc n) := suc n + sum' n
         };
-    } in sum';
+     in sum';
 
   mutrec : IO;
-  mutrec := let {
+  mutrec := let
       terminating
       f : Nat → Nat;
       terminating
@@ -23,7 +23,7 @@ module test034;
       f x := if (x < 1) 1 (g (sub x 1) + 2 * x);
       g x := if (x < 1) 1 (x + h (sub x 1));
       h x := if (x < 1) 1 (x * f (sub x 1));
-    } in printNatLn (f 5)
+    in printNatLn (f 5)
     >> printNatLn (f 10)
     >> printNatLn (g 5)
     >> printNatLn (h 5);
diff --git a/tests/Compilation/positive/test037.juvix b/tests/Compilation/positive/test037.juvix
index fe57aed16..0895515ca 100644
--- a/tests/Compilation/positive/test037.juvix
+++ b/tests/Compilation/positive/test037.juvix
@@ -8,13 +8,13 @@ module test037;
         (x :: _) := x
         | nil := id
       }
-    (let {
+    (let
         y : Nat → Nat;
         y := id;
-      } in (let {
+      in (let
           z : (Nat → Nat) → Nat → Nat;
           z := id;
-        } in case l λ {   (_ :: _) := id } z)
+        in case l λ {   (_ :: _) := id } z)
       y)
     7;
 
diff --git a/tests/negative/LetMissingClause.juvix b/tests/negative/LetMissingClause.juvix
index 63955c6dc..1ec8e66f2 100644
--- a/tests/negative/LetMissingClause.juvix
+++ b/tests/negative/LetMissingClause.juvix
@@ -1,6 +1,6 @@
 module LetMissingClause;
   id : {A : Type} → A → A;
-  id {A} := let {
+  id {A} := let
       id' : A → A;
-    } in id';
+     in id';
 end;
diff --git a/tests/positive/SignatureWithBody.juvix b/tests/positive/SignatureWithBody.juvix
index f6264c161..0d418a80f 100644
--- a/tests/positive/SignatureWithBody.juvix
+++ b/tests/positive/SignatureWithBody.juvix
@@ -6,10 +6,10 @@ module SignatureWithBody;
       | _ := false
     };
 
-  isNull' : {A : Type} → List A → Bool := let {
+  isNull' : {A : Type} → List A → Bool := let
       aux : {A : Type} → List A → Bool := λ {
           | nil := true
           | _ := false
         };
-    } in aux;
+     in aux;
 end;
diff --git a/tests/positive/StdlibList/Data/List.juvix b/tests/positive/StdlibList/Data/List.juvix
index 48fd42d4a..f28e3668c 100644
--- a/tests/positive/StdlibList/Data/List.juvix
+++ b/tests/positive/StdlibList/Data/List.juvix
@@ -12,21 +12,21 @@ match : {A : Type} → {B : Type} → A → (A → B) → B;
 match x f := f x;
 
 foldr : (a : Type) → (b : Type) → (a → b → b) → b → List a → b;
-foldr _ _ _ z (nil _) := z;
-foldr a b f z (:: _ h hs) := f h (foldr a b f z hs);
+foldr _ _ _ z nil := z;
+foldr a b f z (:: h hs) := f h (foldr a b f z hs);
 
 foldl : (a : Type) → (b : Type) → (b → a → b) → b → List a → b;
-foldl a b f z (nil _) := z ;
-foldl a b f z (:: _ h hs) := foldl a b f (f z h) hs;
+foldl a b f z nil := z ;
+foldl a b f z (:: h hs) := foldl a b f (f z h) hs;
 
 map : (a : Type) → (b : Type) → (a → b) → List a → List b;
-map _ b f (nil _) := nil b;
-map a b f (:: _ h hs) := :: a (f h) (map a b f hs);
+map _ b f nil := nil;
+map a b f (:: h hs) := :: (f h) (map a b f hs);
 
 filter : (a : Type) → (a → Bool) → List a → List a;
-filter a f (nil _) := nil a;
-filter a f (:: _ h hs) := match (f h) λ {
-  | true := :: a h (filter a f hs)
+filter a f nil := nil;
+filter a f (:: h hs) := match (f h) λ {
+  | true := :: h (filter a f hs)
   | false := filter a f hs
 };
 
@@ -34,24 +34,24 @@ import Data.Nat;
 open Data.Nat;
 
 length : (a : Type) → List a → ℕ;
-length _ (nil _) := zero;
-length a (:: _ _ l) := suc (length a l);
+length _ nil := zero;
+length a (:: _ l) := suc (length a l);
 
 reverse : (a : Type) → List a → List a;
 reverse a l :=
-  let  {
+  let
   rev : List a → List a → List a;
-  rev (nil _) a := a;
-  rev (:: _ x xs) a := rev xs (:: a x a)
-  } in rev l (nil a);
+  rev nil a := a;
+  rev (:: x xs) a := rev xs (:: x a)
+   in rev l nil;
 
 replicate : (a : Type) → ℕ → a → List a;
-replicate a zero _ := nil a;
-replicate a (suc n) x := :: a x (replicate a n x);
+replicate a zero _ := nil;
+replicate a (suc n) x := :: x (replicate a n x);
 
 take : (a : Type) → ℕ → List a → List a;
-take a (suc n) (:: _ x xs) := :: a x (take a n xs);
-take a _ _ := nil a;
+take a (suc n) (:: x xs) := :: x (take a n xs);
+take a _ _ := nil;
 
 import Data.Ord;
 open Data.Ord;
@@ -59,32 +59,32 @@ open Data.Ord;
 import Data.Product;
 open Data.Product;
 
-splitAt : (a : Type) → ℕ → List a → List a;
-splitAt a _ (nil _) := nil a, nil a;
-splitAt a zero xs := , (List a) (List a) (nil a) xs;
-splitAt a (suc zero) (:: _ x xs) := , (List a) (List a) (:: a x (nil a)) xs;
-splitAt a (suc (suc m)) (:: _ x xs) := match (splitAt a m xs) λ {
-    (, la _ xs' xs'') := , la la (:: a x xs') xs''
+splitAt : (a : Type) → ℕ → List a → List a × List a;
+splitAt a _ nil := , nil nil ;
+splitAt a zero xs := , nil xs;
+splitAt a (suc zero) (:: x xs) := , (:: x nil) xs;
+splitAt a (suc (suc m)) (:: x xs) := match (splitAt a m xs) λ {
+    (, xs' xs'') := , (:: x xs') xs''
   };
 
-merge : (a : Type) → (a → a → Ordering) → List a → List a → List a;
-merge a cmp (:: _ x xs) (:: _ y ys) := match (cmp x y) λ {
-    | LT := :: a x (merge a cmp xs (:: a y ys))
-    | _ := :: a y (merge a cmp (:: a x xs) ys)
+terminating merge : (a : Type) → (a → a → Ordering) → List a → List a → List a;
+merge a cmp (:: x xs) (:: y ys) := match (cmp x y) λ {
+    | LT := :: x (merge a cmp xs (:: y ys))
+    | _ := :: y (merge a cmp (:: x xs) ys)
   };
-merge _ _ (nil _) ys := ys;
-merge _ _ xs (nil _) := xs;
+merge _ _ nil ys := ys;
+merge _ _ xs nil := xs;
 
 -- infixr 5 ++; waiting for implicit arguments
 ++ : (a : Type) → List a → List a → List a;
-++ a (nil _) ys := ys;
-++ a (:: _ x xs) ys := :: a x (++ a xs ys);
+++ a nil ys := ys;
+++ a (:: x xs) ys := :: x (++ a xs ys);
 
-quickSort : (a : Type) → (a → a → Ordering) → List a → List a;
-quickSort a _ (nil _) := nil a;
-quickSort a _ (:: _ x (nil _)) := :: a x (nil a);
-quickSort a cmp (:: _ x ys) :=
-  let {
+terminating quickSort : (a : Type) → (a → a → Ordering) → List a → List a;
+quickSort a _ nil := nil;
+quickSort a _ (:: x nil) := :: x nil;
+quickSort a cmp (:: x ys) :=
+  let
     ltx : a → Bool;
     ltx y := match (cmp y x) λ{
       | LT := true
@@ -92,10 +92,8 @@ quickSort a cmp (:: _ x ys) :=
     };
     gex : a → Bool;
     gex y := not (ltx y)
-  } in
-  {
-     ++ a (quickSort a (filter a ltx) ys)
-    (++ a (:: a x (nil a)) (quickSort a (filter a gex) ys))
-  };
+   in
+     ++ a (quickSort a cmp (filter a ltx ys))
+    (++ a (:: x nil) (quickSort a cmp (filter a gex ys)));
 
 end;
diff --git a/tests/smoke/Commands/repl.smoke.yaml b/tests/smoke/Commands/repl.smoke.yaml
index 4b6121184..a99fc8c7d 100644
--- a/tests/smoke/Commands/repl.smoke.yaml
+++ b/tests/smoke/Commands/repl.smoke.yaml
@@ -122,7 +122,7 @@ tests:
     command:
       - juvix
       - repl
-    stdin: "let {x : Nat; x := 2 + 1} in x"
+    stdin: "let x : Nat; x := 2 + 1 in x"
     stdout:
       contains:
         "suc (suc (suc zero))"