fix: Consistently put then on the same line as if

Fixes gluon-lang#495

format/src/pretty_print.rs

@@ -203,9 +203,12 @@ where
             Expr::IfElse(ref body, ref if_true, ref if_false) => {
                 let space = newline(arena, expr);
                 chain![arena;
-                    arena.text("if ").append(pretty(body)).group(),
-                    arena.space(),
-                    "then",
+                    chain![arena;
+                        "if ",
+                        pretty(body),
+                        arena.space(),
+                        "then"
+                    ].group(),
                     space.clone().append(pretty(if_true)).nest(INDENT).group(),
                     space.clone(),
                     "else",
@@ -480,7 +483,7 @@ where
                 self.pretty_expr_(bound.span.end(), body)
             ],
             Expr::MacroExpansion { ref original, .. } => {
-                return self.pretty_expr_(previous_end, original)
+                return self.pretty_expr_(previous_end, original);
             }
             Expr::Error(_) => arena.text("<error>"),
         };
@@ -522,9 +525,12 @@ where
         let arena = self.arena;
         match if_false.value {
             Expr::IfElse(ref body, ref if_true, ref if_false) => chain![arena;
-                arena.text(" if ").append(pretty(body)).group(),
-                arena.space(),
-                "then",
+                chain![arena;
+                    " if ",
+                    pretty(body),
+                    arena.space(),
+                    "then"
+                ].group(),
                 space.clone().append(pretty(if_true)).nest(INDENT).group(),
                 space.clone(),
                 "else",
@@ -1026,7 +1032,7 @@ fn newline<'a, Id, A>(
 
 fn forced_new_line<Id>(expr: &SpannedExpr<Id>) -> bool {
     match expr.value {
-        Expr::LetBindings(..) | Expr::Match(..) | Expr::TypeBindings(..) => true,
+        Expr::LetBindings(..) | Expr::Match(..) | Expr::TypeBindings(..) | Expr::Do(..) => true,
         Expr::Lambda(ref lambda) => forced_new_line(&lambda.body),
         Expr::Tuple { ref elems, .. } => elems.iter().any(forced_new_line),
         Expr::Record {

format/tests/pretty_print.rs

@@ -373,15 +373,43 @@ test abc 1232 ""
 #[test]
 fn if_else_multiple() {
     let expr = r#"
-if x
-then y
-else if z
-then w
+if x then y
+else if z then w
 else 0
 "#;
     assert_diff!(&format_expr(expr).unwrap(), expr, " ", 0);
 }
 
+#[test]
+fn if_else_multiple_let_multiline_1() {
+    let expr = r#"
+if x then
+    f 123 483
+else if z then
+    "12312"
+else
+    do x = 1
+    x
+"#;
+    assert_diff!(&format_expr(expr).unwrap(), expr, " ", 0);
+}
+
+#[test]
+fn if_else_multiple_multiline_2() {
+    let expr = r#"
+if x then
+    do z = io
+    io
+else if z then
+    type X = Int
+    123
+else
+    let x = 1
+    x
+"#;
+    assert_diff!(&format_expr(expr).unwrap(), expr, " ", 0);
+}
+
 #[test]
 fn fully_break_function_type() {
     let expr = r#"

repl/src/repl.glu

@@ -13,27 +13,46 @@ let { ReadlineError } = import! rustyline_types
 let { Color } = import! repl_types
 let repl_prim = import! repl.prim
 let { (<<), (<|) } = import! std.function
-let effect @ { Eff, Reader, Lift, ask, ? } = import! std.effect
+let effect @ { Eff, Reader, Lift, ask, asks, ? } = import! std.effect
 let { Applicative, wrap, (*>) } = import! std.applicative
 let { flat_map, (>>=) } = import! std.monad
 let { foldl } = import! std.foldable
 
 let { (<>) } = import! std.prelude
 let (++) = (<>)
 
-type ReplEffect r a = [| reader : Reader CpuPool, lift : Lift IO | r |] a
-
-let run_interruptible_io cpu_pool action : CpuPool
-        -> IO String
+rec
+type ReplEffect r a = [| reader : Reader Repl, lift : Lift IO | r |] a
+type Repl = {
+    commands : Commands,
+    editor : Editor,
+    cpu_pool : CpuPool,
+    color : Color,
+    prompt : String
+}
+type ReplAction =
+    | Continue
+    | Quit
+type Cmd = {
+    name : String,
+    alias : String,
+    info : String,
+    action : String -> Eff (ReplEffect r) ReplAction
+}
+type Commands = Map String Cmd
+in
+let run_interruptible_io action :
+        IO String
         -> Eff (ReplEffect r) (Result String String)
     =
+    do cpu_pool = asks (\r -> r.cpu_pool)
     do eval_thread = effect.lift <| thread.new_thread ()
     let interruptible_action = repl_prim.finish_or_interrupt cpu_pool eval_thread action
     effect.lift
         <| io.catch (io.functor.map Ok interruptible_action) (wrap << Err)
 
 
-let load_file cpu_pool filename : CpuPool -> String -> Eff (ReplEffect r) String =
+let load_file filename : String -> Eff (ReplEffect r) String =
     let last_slash =
         match string.rfind filename "/" with
         | None -> 0
@@ -44,35 +63,24 @@ let load_file cpu_pool filename : CpuPool -> String -> Eff (ReplEffect r) String
         do result = io.load_script modulename expr
         wrap result
 
-    do result = run_interruptible_io cpu_pool action
+    do result = run_interruptible_io action
     match result with
     | Ok x -> wrap x
     | Err x -> wrap x
 
-let run_file cpu_pool filename : CpuPool -> String -> Eff (ReplEffect r) () =
+let run_file filename : String -> Eff (ReplEffect r) () =
     let action =
         do expr = io.read_file_to_string filename
         do result = io.run_expr expr
         wrap (result.value ++ " : " ++ result.typ)
 
-    do result = run_interruptible_io cpu_pool action
+    do result = run_interruptible_io action
     effect.lift
         <| (match result with
         | Ok _ -> io.println ""
         | Err x -> io.println x)
 
-type ReplAction =
-    | Continue
-    | Quit
-type Cmd = {
-    name : String,
-    alias : String,
-    info : String,
-    action : String -> Eff (ReplEffect r) ReplAction
-}
-type Commands = Map String Cmd
-
-let make_commands cpu_pool : CpuPool -> Commands =
+let commands : Commands =
     let print_result result =
         effect.lift
             <| (match result with
@@ -121,14 +129,14 @@ let make_commands cpu_pool : CpuPool -> Commands =
             info = "Loads the file at \'folder/module.ext\' and stores it at \'module\'",
             action
             = \arg ->
-                (load_file cpu_pool arg >>= (effect.lift << io.println))
+                (load_file arg >>= (effect.lift << io.println))
                     *> wrap Continue,
         },
         {
             name = "script",
             alias = "s",
             info = "Runs the script at `FILENAME`",
-            action = \arg -> run_file cpu_pool arg *> wrap Continue,
+            action = \arg -> run_file arg *> wrap Continue,
         },
         {
             name = "debug",
@@ -190,45 +198,31 @@ let do_command commands line : Commands -> String -> Eff (ReplEffect r) ReplActi
         effect.lift
             <| io.println "Expected a command such as `:h`" *> wrap Continue
 
-let store line : String -> IO ReplAction =
-    let line = string.trim line
-    match string.find line " " with
-    | Some bind_end ->
-        let binding = string.slice line 0 bind_end
-        let expr = string.slice line bind_end (string.len line)
-        io.load_script binding expr *> wrap Continue
-    | None -> io.println "Expected binding in definition" *> wrap Continue
-
-type Repl = {
-    commands : Commands,
-    editor : Editor,
-    cpu_pool : CpuPool,
-    color : Color,
-    prompt : String
-}
+let loop _ : () -> Eff (ReplEffect r) () =
+    do repl = ask
 
-let loop repl : Repl -> Eff (ReplEffect r) () =
     let run_line line =
         if string.is_empty (string.trim line) then
             wrap Continue
         else if string.starts_with line ":" then
             do_command repl.commands line
         else
+            do cpu_pool = asks (\r -> r.cpu_pool)
             let action =
                 do eval_thread = thread.new_thread ()
                 let eval_action = repl_prim.eval_line repl.color line
-                repl_prim.finish_or_interrupt repl.cpu_pool eval_thread eval_action
+                repl_prim.finish_or_interrupt cpu_pool eval_thread eval_action
             effect.lift
                 <| io.catch action io.println *> wrap Continue
 
     do line_result = effect.lift <| rustyline.readline repl.editor repl.prompt
     match line_result with
     | Err Eof -> wrap ()
-    | Err Interrupted -> loop repl
+    | Err Interrupted -> loop ()
     | Ok line ->
         do continue = run_line line
         match continue with
-        | Continue -> loop repl
+        | Continue -> loop ()
         | Quit ->
             do _ = effect.lift <| rustyline.save_history repl.editor
             wrap ()
@@ -237,8 +231,7 @@ let run color prompt : Color -> String -> IO () =
     do _ = io.println "gluon (:h for help, :q to quit)"
     do editor = rustyline.new_editor ()
     do cpu_pool = repl_prim.new_cpu_pool 1
-    let commands = make_commands cpu_pool
     let repl = { commands, editor, cpu_pool, color, prompt }
-    effect.run_lift (effect.run_reader cpu_pool (loop repl))
+    effect.run_lift (effect.run_reader repl (loop ()))
 
 run

std/parser.glu

@@ -151,10 +151,9 @@ let take1 predicate : (Char -> Bool) -> Parser String =
         let take_ stream2 =
             match uncons stream2 with
             | Some record ->
-                if predicate record.char
-                then take_ record.rest
-                else if stream.start == stream2.start
-                then Err { position = stream.start, message = "Unexpected token" }
+                if predicate record.char then take_ record.rest
+                else if stream.start == stream2.start then
+                    Err { position = stream.start, message = "Unexpected token" }
                 else Ok {
                             value = string.slice stream.buffer stream.start stream2.start,
                             buffer = stream2,
@@ -220,8 +219,7 @@ let one_of s : String -> Parser Char =
                 False
             else
                 let c = string.char_at s i
-                if first == c
-                then True
+                if first == c then True
                 else one_of_ (i + char.len_utf8 c)
         one_of_ 0)
         <|> fail ("Expected one of `" <> s <> "`")
@@ -240,7 +238,8 @@ let sep_by parser sep : Parser a -> Parser b -> Parser (List a) =
 /// Like `sep_by1` but applies the function returned by `op` on the left fold of successive parses
 let chainl1 p op : Parser a -> Parser (a -> a -> a) -> Parser a =
     do l = p
-    let rest x = (
+    let rest x =
+        (
         do f = op
         do r = p
         rest (f x r)) <|> wrap x

std/stream.glu

@@ -28,8 +28,7 @@ let from f : (Int -> Option a) -> Stream a =
 
 let of xs : Array a -> Stream a =
     from (\i ->
-        if i < array.len xs
-        then Some (array.index xs i)
+        if i < array.len xs then Some (array.index xs i)
         else None)
 
 let repeat x : a -> Stream a =

std/test.glu

@@ -29,13 +29,11 @@ let group = Group
 let assert x = if x then () else error "Assertion failed"
 
 let assert_eq l r : [Show a] -> [Eq a] -> a -> a -> Eff [| writer : Test | r |] () =
-    if l == r
-    then wrap ()
+    if l == r then wrap ()
     else effect.tell (Cons ("Assertion failed: " <> show l <> " != " <> show r) Nil)
 
 let assert_neq l r : [Show a] -> [Eq a] -> a -> a -> Eff [| writer : Test | r |] () =
-    if l /= r
-    then wrap ()
+    if l /= r then wrap ()
     else effect.tell (Cons ("Assertion failed: " <> show l <> " == " <> show r) Nil)
 
 rec let run_raw test : Eff [| writer : Test | r |] a -> Eff [| | r |] (List String) =