Array-based List type

.vscode/launch.json

@@ -95,9 +95,9 @@
             "type": "coreclr",
             "request": "launch",
             "name": "bench-compile (.NET)",
-            "program": "${workspaceFolder}/src/fable-standalone/test/bench-compiler/bin/Debug/netcoreapp2.1/bench-compiler.dll",
+            "program": "${workspaceFolder}/src/fable-standalone/test/bench-compiler/bin/Debug/netcoreapp3.1/bench-compiler.dll",
             // "args": ["${workspaceRoot}/tests/Main/Fable.Tests.fsproj", "out-tests", "--commonjs"],
-            "args": ["${workspaceRoot}/../fable-test/fable-test.fsproj", "out-test", "--typescript"],
+            "args": ["${workspaceRoot}/../fable-test/fable-test.fsproj", "out-test"],
             "cwd": "${workspaceFolder}/src/fable-standalone/test/bench-compiler"
         },
         {

src/Fable.Transforms/FSharp2Fable.Util.fs

@@ -1203,6 +1203,10 @@ module Util =
             else
                 // Indexed properties keep the get_/set_ prefix and are compiled as methods
                 if indexedProp then memb.CompiledName, false, false
+                // performance optimization, compile get_Current as instance call instead of a getter
+                elif memb.FullName = "System.Collections.IEnumerator.get_Current" ||
+                     memb.FullName = "System.Collections.Generic.IEnumerator.get_Current"
+                then getMemberDisplayName memb, false, false
                 else getMemberDisplayName memb, isGetter, isSetter
         if isGetter then
             let t = memb.ReturnParameter.Type |> makeType Map.empty

src/Fable.Transforms/FSharp2Fable.fs

@@ -206,6 +206,11 @@ let private getAttachedMemberInfo com ctx r nonMangledNameConflicts
                     let name, isGetter, isSetter =
                         // For indexed properties, keep the get_/set_ prefix and compile as method
                         if indexedProp then sign.Name, false, false
+                        // performance optimization, compile get_Current as instance call instead of a getter
+                        elif sign.Name = "get_Current" &&
+                            (fullName = Some "System.Collections.IEnumerator" ||
+                             fullName = Some "System.Collections.Generic.IEnumerator`1")
+                        then Naming.removeGetSetPrefix sign.Name, false, false
                         else Naming.removeGetSetPrefix sign.Name, isGetter, isSetter
                     // Setters can have same name as getters, assume there will always be a getter
                     if not isSetter && nonMangledNameConflicts declaringEntityName name then

src/Fable.Transforms/Fable2Babel.fs

@@ -439,7 +439,7 @@ module Annotation =
             makeNativeTypeAnnotation com ctx [genArg] "Array"
 
     let makeListTypeAnnotation com ctx genArg =
-        makeImportTypeAnnotation com ctx [genArg] "Types" "List"
+        makeImportTypeAnnotation com ctx [genArg] "List" "List"
 
     let makeUnionTypeAnnotation com ctx genArgs =
         List.map (typeAnnotation com ctx) genArgs
@@ -655,12 +655,6 @@ module Util =
         | [] -> expr
         | m::ms -> get None expr m |> getParts ms
 
-    let makeList com ctx headAndTail =
-        match headAndTail with
-        | None -> [||]
-        | Some(TransformExpr com ctx head, TransformExpr com ctx tail) -> [|head; tail|]
-        |> libConsCall com ctx "Types" "List"
-
     let makeArray (com: IBabelCompiler) ctx exprs =
         List.mapToArray (fun e -> com.TransformAsExpr(ctx, e)) exprs
         |> ArrayExpression :> Expression
@@ -893,12 +887,17 @@ module Util =
         | Fable.NewTuple vals -> makeArray com ctx vals
         // Optimization for bundle size: compile list literals as List.ofArray
         | Replacements.ListLiteral(exprs, t) ->
-            match exprs with
-            | [] -> makeList com ctx None
-            | [expr] -> Some(expr, Fable.Value(Fable.NewList (None,t), None)) |> makeList com ctx
-            | exprs -> [|makeArray com ctx exprs|] |> libCall com ctx r "List" "ofArray"
+            [|List.rev exprs |> makeArray com ctx|]
+            |> libCall com ctx r "List" "newList"
+            // match exprs with
+            // | [] -> libCall com ctx r "List" "empty" [||]
+            // | [TransformExpr com ctx expr] -> libCall com ctx r "List" "singleton" [|expr|]
+            // | exprs -> [|makeArray com ctx exprs|] |> libCall com ctx r "List" "ofArray"
         | Fable.NewList (headAndTail, _) ->
-            makeList com ctx headAndTail
+            match headAndTail with
+            | None -> libCall com ctx r "List" "empty" [||]
+            | Some(TransformExpr com ctx head, TransformExpr com ctx tail) ->
+                libCall com ctx r "List" "cons" [|head; tail|]
         | Fable.NewOption (value, t) ->
             match value with
             | Some (TransformExpr com ctx e) ->
@@ -1086,8 +1085,10 @@ module Util =
         match getKind with
         | Fable.ByKey(Fable.ExprKey(TransformExpr com ctx prop)) -> getExpr range expr prop
         | Fable.ByKey(Fable.FieldKey field) -> get range expr field.Name
-        | Fable.ListHead -> get range expr "head"
-        | Fable.ListTail -> get range expr "tail"
+        // | Fable.ListHead -> get range expr "Head"
+        // | Fable.ListTail -> get range expr "Tail"
+        | Fable.ListHead -> libCall com ctx range "List" "head" [|expr|]
+        | Fable.ListTail -> libCall com ctx range "List" "tail" [|expr|]
         | Fable.TupleIndex index -> getExpr range expr (ofInt index)
         | Fable.OptionValue ->
             if mustWrapOption typ || com.Options.Typescript
@@ -1143,9 +1144,9 @@ module Util =
             let op = if nonEmpty then BinaryUnequal else BinaryEqual
             upcast BinaryExpression(op, com.TransformAsExpr(ctx, expr), NullLiteral(), ?loc=range)
         | Fable.ListTest nonEmpty ->
-            let expr = com.TransformAsExpr(ctx, expr)
-            let op = if nonEmpty then BinaryUnequal else BinaryEqual
-            upcast BinaryExpression(op, get None expr "tail", NullLiteral(), ?loc=range)
+            // let expr = get range (com.TransformAsExpr(ctx, expr)) "IsEmpty"
+            let expr = libCall com ctx range "List" "isEmpty" [|com.TransformAsExpr(ctx, expr)|]
+            if nonEmpty then upcast UnaryExpression(UnaryNot, expr, ?loc=range) else expr
         | Fable.UnionCaseTest tag ->
             let expected = ofInt tag
             let actual = com.TransformAsExpr(ctx, expr) |> getUnionExprTag None

src/Fable.Transforms/Replacements.fs

@@ -1664,6 +1664,8 @@ let resizeArrays (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (this
         Helper.LibCall(com, "Seq", "filter", t, [arg; ar], ?loc=r) |> toArray com t |> Some
     | "AddRange", Some ar, [arg] ->
         Helper.LibCall(com, "Array", "addRangeInPlace", t, [arg; ar], ?loc=r) |> Some
+    | "GetRange", Some ar, [idx; cnt] ->
+        Helper.LibCall(com, "Array", "getSubArray", t, [ar; idx; cnt], ?loc=r) |> Some
     | "Contains", Some (MaybeCasted(ar)), [arg] ->
         match ar.Type with
         | Array _ ->
@@ -1771,29 +1773,26 @@ let arrayModule (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (_: Ex
         Helper.LibCall(com, "Array", meth, t, args, i.SignatureArgTypes, ?loc=r) |> Some
 
 let lists (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (thisArg: Expr option) (args: Expr list) =
+    let meth = Naming.removeGetSetPrefix i.CompiledName |> Naming.lowerFirst
     match i.CompiledName, thisArg, args with
-    // Use methods for Head and Tail (instead of Get(ListHead) for example) to check for empty lists
-    | ReplaceName
-      [ "get_Head",   "head"
-        "get_Tail",   "tail"
-        "get_Item",   "item"
-        "get_Length", "length"
-        "GetSlice",   "slice" ] methName, Some x, _ ->
-            let args = match args with [ExprType Unit] -> [x] | args -> args @ [x]
-            Helper.LibCall(com, "List", methName, t, args, i.SignatureArgTypes, ?loc=r) |> Some
-    | "get_IsEmpty", Some x, _ -> Test(x, ListTest false, r) |> Some
-    | "get_Empty", None, _ -> NewList(None, (genArg com ctx r 0 i.GenericArgs)) |> makeValue r |> Some
-    | "Cons", None, [h;t] -> NewList(Some(h,t), (genArg com ctx r 0 i.GenericArgs)) |> makeValue r |> Some
+    | ("get_Head" | "get_Tail" | "get_IsEmpty" | "get_Length"), Some x, _ ->
+        Helper.LibCall(com, "List", meth, t, [x], i.SignatureArgTypes, ?loc=r) |> Some
+        // get r t x meth |> Some
+    | ("get_Item" | "GetSlice"), Some x, _ ->
+        Helper.LibCall(com, "List", meth, t, args @ [x], i.SignatureArgTypes, ?loc=r) |> Some
+    | ("get_Empty" | "Cons"), None, _ ->
+        Helper.LibCall(com, "List", meth, t, args, i.SignatureArgTypes, ?loc=r) |> Some
     | ("GetHashCode" | "Equals" | "CompareTo"), Some callee, _ ->
         Helper.InstanceCall(callee, i.CompiledName, t, args, i.SignatureArgTypes, ?loc=r) |> Some
     | _ -> None
 
 let listModule (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (_: Expr option) (args: Expr list) =
     match i.CompiledName, args with
-    | "IsEmpty", [x] -> Test(x, ListTest false, r) |> Some
-    | "Empty", _ -> NewList(None, (genArg com ctx r 0 i.GenericArgs)) |> makeValue r |> Some
-    | "Singleton", [x] ->
-        NewList(Some(x, Value(NewList(None, t), None)), (genArg com ctx r 0 i.GenericArgs)) |> makeValue r |> Some
+    // | ("Head" | "Tail" | "IsEmpty") as meth, [x] -> get r t x (Naming.lowerFirst meth) |> Some
+    // | "IsEmpty", [x] -> Test(x, ListTest false, r) |> Some
+    // | "Empty", _ -> NewList(None, (genArg com ctx r 0 i.GenericArgs)) |> makeValue r |> Some
+    // | "Singleton", [x] ->
+    //     NewList(Some(x, Value(NewList(None, t), None)), (genArg com ctx r 0 i.GenericArgs)) |> makeValue r |> Some
     // Use a cast to give it better chances of optimization (e.g. converting list
     // literals to arrays) after the beta reduction pass
     | "ToSeq", [x] -> toSeq t x |> Some
@@ -2586,8 +2585,8 @@ let enumerables (com: ICompiler) (ctx: Context) r t (i: CallInfo) (thisArg: Expr
 
 let enumerators (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (thisArg: Expr option) (args: Expr list) =
     match i.CompiledName, thisArg with
-    | "get_Current", Some x -> get r t x "Current" |> Some
-    | meth, Some x -> Helper.InstanceCall(x, meth, t, args, i.SignatureArgTypes, ?loc=r) |> Some
+    // | "get_Current", Some x -> get r t x "Current" |> Some
+    | meth, Some x -> Helper.InstanceCall(x, Naming.removeGetSetPrefix meth, t, args, i.SignatureArgTypes, ?loc=r) |> Some
     | _ -> None
 
 let events (com: ICompiler) (ctx: Context) r (t: Type) (i: CallInfo) (thisArg: Expr option) (args: Expr list) =

src/fable-library/Array.fs

@@ -101,8 +101,7 @@ module Helpers =
 
 open Helpers
 
-let private indexNotFound() =
-    failwith "An index satisfying the predicate was not found in the collection."
+let private indexNotFoundMsg = "An index satisfying the predicate was not found in the collection."
 
 // Pay attention when benchmarking to append and filter functions below
 // if implementing via native JS array .concat() and .filter() do not fall behind due to js-native transitions.
@@ -445,15 +444,15 @@ let partition (f: 'T -> bool) (source: 'T[]) ([<Inject>] cons: IArrayCons<'T>) =
 let find (predicate: 'T -> bool) (array: 'T[]): 'T =
     match findImpl predicate array with
     | Some res -> res
-    | None -> indexNotFound()
+    | None -> failwith indexNotFoundMsg
 
 let tryFind (predicate: 'T -> bool) (array: 'T[]): 'T option =
     findImpl predicate array
 
 let findIndex (predicate: 'T -> bool) (array: 'T[]): int =
     match findIndexImpl predicate array with
     | index when index > -1 -> index
-    | _ -> indexNotFound()
+    | _ -> failwith indexNotFoundMsg
 
 let tryFindIndex (predicate: 'T -> bool) (array: 'T[]): int option =
     match findIndexImpl predicate array with
@@ -463,7 +462,7 @@ let tryFindIndex (predicate: 'T -> bool) (array: 'T[]): int option =
 let pick chooser (array: _[]) =
     let rec loop i =
         if i >= array.Length then
-            indexNotFound()
+            failwith indexNotFoundMsg
         else
             match chooser array.[i] with
             | None -> loop(i+1)
@@ -480,7 +479,7 @@ let tryPick chooser (array: _[]) =
 
 let findBack predicate (array: _[]) =
     let rec loop i =
-        if i < 0 then indexNotFound()
+        if i < 0 then failwith indexNotFoundMsg
         elif predicate array.[i] then array.[i]
         else loop (i - 1)
     loop (array.Length - 1)
@@ -501,7 +500,7 @@ let findLastIndex predicate (array: _[]) =
 
 let findIndexBack predicate (array: _[]) =
     let rec loop i =
-        if i < 0 then indexNotFound()
+        if i < 0 then failwith indexNotFoundMsg
         elif predicate array.[i] then i
         else loop (i - 1)
     loop (array.Length - 1)