Fix union/record string formatting (#2189)

* Fix union/record string formatting

* Fix tests

* Minor fixes

Author: alfonsogarciacaro

.vscode/launch.json

@@ -4,6 +4,15 @@
     // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
     "version": "0.2.0",
     "configurations": [
+        {
+            "name": "Attach to Node",
+            "port": 9229,
+            "request": "attach",
+            "skipFiles": [
+                "<node_internals>/**"
+            ],
+            "type": "pwa-node"
+        },
         {
             "args": [
                 "${workspaceFolder}/build/tests",

src/Fable.Cli/Main.fs

@@ -318,6 +318,14 @@ type State =
       ErroredFiles: Set<string>
       TestInfo: TestInfo option }
 
+let filterFiles (exclude: string option) (files: string[]) =
+    files
+    |> Array.filter (fun file -> file.EndsWith(".fs") || file.EndsWith(".fsx"))
+    |> fun filesToCompile ->
+        match exclude with
+        | Some exclude -> filesToCompile |> Array.filter (fun x -> not(x.Contains(exclude))) // Use regex?
+        | None -> filesToCompile
+
 let rec startCompilation (changes: Set<string>) (state: State) = async {
     let cracked, parsed, filesToCompile =
         match state.ProjectCrackedAndParsed with
@@ -370,13 +378,9 @@ let rec startCompilation (changes: Set<string>) (state: State) = async {
 
     let filesToCompile =
         filesToCompile
-        |> Array.filter (fun file -> file.EndsWith(".fs") || file.EndsWith(".fsx"))
+        |> filterFiles state.CliArgs.Exclude
         |> Array.append (Set.toArray state.ErroredFiles)
         |> Array.distinct
-        |> fun filesToCompile ->
-            match state.CliArgs.Exclude with
-            | Some exclude -> filesToCompile |> Array.filter (fun x -> not(x.Contains(exclude))) // Use regex?
-            | None -> filesToCompile
 
     let logs = getFSharpErrorLogs parsed.Project
 
@@ -442,10 +446,12 @@ let rec startCompilation (changes: Set<string>) (state: State) = async {
 
         let! changes = Watcher.AwaitChanges [
             cracked.ProjectFile
-            yield! cracked.SourceFiles |> Seq.choose (fun f ->
-                let path = f.NormalizedFullPath
-                if Naming.isInFableHiddenDir(path) then None
-                else Some path)
+            yield! cracked.SourceFiles
+                |> Array.choose (fun f ->
+                    let path = f.NormalizedFullPath
+                    if Naming.isInFableHiddenDir(path) then None
+                    else Some path)
+                |> filterFiles state.CliArgs.Exclude
         ]
         return!
             { state with ProjectCrackedAndParsed = Some(cracked, parsed)

src/Fable.Transforms/Replacements.fs

@@ -407,13 +407,15 @@ let toString com (ctx: Context) r (args: Expr list) =
         | Number Int32 -> Helper.LibCall(com, "Util", "int32ToString", String, args)
         | Number _ -> Helper.InstanceCall(head, "toString", String, tail)
         | DeclaredType(ent, _) ->
-            let moduleName, methodName =
-                if ent.IsFSharpUnion then "Types", "unionToString"
-                elif ent.IsFSharpRecord then "Types", "recordToString"
-                elif ent.IsValueType then "Types", "objectToString"
-                else "Types", "objectToString"
-            Helper.LibCall(com, moduleName, methodName, String, [head], ?loc=r)
-        | _ -> Helper.GlobalCall("String", String, [head])
+            let methodName =
+                if ent.IsFSharpUnion then "unionToString"
+                elif ent.IsFSharpRecord then "recordToString"
+                elif ent.FullName = Types.ienumerableGeneric then "seqToString"
+                else "objectToString"
+            Helper.LibCall(com, "String", methodName, String, [head], ?loc=r)
+        | Array _ | List _ ->
+            Helper.LibCall(com, "String", "seqToString", String, [head], ?loc=r)
+        | _ -> Helper.LibCall(com, "String", "toString", String, [head], ?loc=r)
 
 let getParseParams (kind: NumberExtKind) =
     let isFloatOrDecimal, numberModule, unsigned, bitsize =

src/fable-library/Seq.ts

@@ -79,11 +79,9 @@ function __failIfNone<T>(res: Option<T>) {
 }
 
 function makeSeq<T>(f: () => Iterator<T>): Iterable<T> {
-  const seq = {
+  return {
     [Symbol.iterator]: f,
-    toString: () => "seq [" + Array.from(seq).join("; ") + "]",
   };
-  return seq;
 }
 
 function isArrayOrBufferView<T>(xs: Iterable<T>): xs is T[] {

src/fable-library/String.ts

@@ -2,12 +2,17 @@ import { toString as dateToString } from "./Date.js";
 import Decimal from "./Decimal.js";
 import Long, * as _Long from "./Long.js";
 import { escape } from "./RegExp.js";
+import { isIterable, isUnionLike } from "./Util.js";
+
+type Numeric = number | Long | Decimal;
+
+export interface IStringable {
+  ToString(): string;
+}
 
 const fsFormatRegExp = /(^|[^%])%([0+\- ]*)(\d+)?(?:\.(\d+))?(\w)/;
 const formatRegExp = /\{(\d+)(,-?\d+)?(?:\:([a-zA-Z])(\d{0,2})|\:(.+?))?\}/g;
 
-type Numeric = number | Long | Decimal;
-
 // These are used for formatting and only take longs and decimals into account (no bigint)
 function isNumeric(x: any) {
   return typeof x === "number" || x instanceof Long || x instanceof Decimal;
@@ -219,6 +224,8 @@ function formatOnce(str2: string, rep: any) {
           rep = String(rep);
           break;
       }
+    } else {
+      rep = toString(rep);
     }
     padLength = parseInt(padLength, 10);
     if (!isNaN(padLength)) {
@@ -309,6 +316,8 @@ export function format(str: string, ...args: any[]) {
       }
     } else if (rep instanceof Date) {
       rep = dateToString(rep, pattern || format);
+    } else {
+      rep = toString(rep)
     }
     padLength = parseInt((padLength || " ").substring(1), 10);
     if (!isNaN(padLength)) {
@@ -318,6 +327,80 @@ export function format(str: string, ...args: any[]) {
   });
 }
 
+export function isStringable<T>(x: T | IStringable): x is IStringable {
+  return x != null && typeof (x as IStringable).ToString === "function";
+}
+
+function unionToStringPrivate(self: any): string {
+  const name = self.cases()[self.tag];
+  if (self.fields.length === 0) {
+    return name;
+  } else {
+    let fields = "";
+    let withParens = true;
+    if (self.fields.length === 1) {
+      const field = toString(self.fields[0]);
+      withParens = field.indexOf(" ") >= 0;
+      fields = field;
+    }
+    else {
+      fields = self.fields.map((x: any) => toString(x)).join(", ");
+    }
+    return name + (withParens ? " (" : " ") + fields + (withParens ? ")" : "");
+  }
+}
+
+export function unionToString(self: any) {
+  return isStringable(self) ? self.ToString() : unionToStringPrivate(self);
+}
+
+function recordToStringPrivate(self: any, callStack=0): string {
+  return callStack > 10
+    ? Object.getPrototypeOf(self).constructor.name
+    : "{ " + Object.entries(self).map(([k, v]) => k + " = " + toString(v, callStack)).join("\n  ") + " }";
+}
+
+export function recordToString(self: any): string {
+  return isStringable(self) ? self.ToString() : recordToStringPrivate(self);
+}
+
+export function objectToString(self: any): string {
+  return isStringable(self) ? self.ToString() : Object.getPrototypeOf(self).constructor.name;
+}
+
+export function seqToString<T>(self: Iterable<T>): string {
+  let count = 0;
+  let str = "[";
+  for (let x of self) {
+    if (count === 0) {
+      str += toString(x);
+    } else if (count === 100) {
+      str += "; ...";
+      break;
+    } else {
+      str += "; " + toString(x);
+    }
+    count++;
+  }
+  return str + "]";
+}
+
+export function toString(x: any, callStack=-1): string {
+  if (x == null || typeof x !== "object") {
+    return String(x);
+  } else if (isStringable(x)) {
+    return x.ToString();
+  } else if (isIterable(x)) {
+    return seqToString(x);
+  } else if (isUnionLike(x)) {
+    return unionToStringPrivate(x);
+  } else {
+    // TODO: Defaulting to recordToString until we have a way
+    // to tell records apart from other objects in runtime
+    return recordToStringPrivate(x, callStack + 1);
+  }
+}
+
 export function endsWith(str: string, search: string) {
   const idx = str.lastIndexOf(search);
   return idx >= 0 && idx === str.length - search.length;

src/fable-library/Types.ts

@@ -1,12 +1,4 @@
-import { IEquatable, IComparable, combineHashCodes, compare, compareArrays, equalArrays, equals, isComparable, isEquatable, isHashable, sameConstructor, isStringable, numberHash, structuralHash } from "./Util.js";
-
-export function objectToString(self: any) {
-  if (isStringable(self)) {
-    return self.ToString();
-  } else {
-    return Object.getPrototypeOf(self).constructor.name;
-  }
-}
+import { IEquatable, IComparable, combineHashCodes, compare, compareArrays, equalArrays, equals, isComparable, isEquatable, isHashable, sameConstructor, numberHash, structuralHash } from "./Util.js";
 
 // export class SystemObject implements IEquatable<any> {
 
@@ -66,17 +58,17 @@ export class List<T> implements IEquatable<List<T>>, IComparable<List<T>>, Itera
     };
   }
 
-  public toJSON() {
-    return Array.from(this);
-  }
+  // public toJSON() {
+  //   return Array.from(this);
+  // }
 
-  public toString() {
-    return this.ToString();
-  }
+  // public toString() {
+  //   return this.ToString();
+  // }
 
-  public ToString() {
-    return "[" + Array.from(this).join("; ") + "]";
-  }
+  // public ToString() {
+  //   return "[" + Array.from(this).join("; ") + "]";
+  // }
 
   public GetHashCode() {
     const hashes = Array.from(this).map(structuralHash);
@@ -92,19 +84,6 @@ export class List<T> implements IEquatable<List<T>>, IComparable<List<T>>, Itera
   }
 }
 
-export function unionToString(self: any) {
-  const name = self.cases()[self.tag];
-  if (isStringable(self)) {
-    return self.ToString();
-  } else if (self.fields.length === 0) {
-    return name;
-  } else if (self.fields.length === 1) {
-    return name + " " + String(self.fields[0]);
-  } else {
-    return name + " (" + self.fields.map((x: any) => String(x)).join(",") + ")";
-  }
-}
-
 export function unionToJson(self: any) {
   const name = self.cases()[self.tag];
   return self.fields.length === 0 ? name : [name].concat(self.fields);
@@ -186,14 +165,6 @@ export function unionCompareTo(self: any, other: any) {
 //   }
 // }
 
-export function recordToString(self: any) {
-  if (isStringable(self)) {
-    return self.ToString();
-  } else {
-    return "{" + Object.entries(self).map(([k, v]) => k + " = " + String(v)).join(";\n ") + "}";
-  }
-}
-
 export function recordToJson(self: any, getFieldNames?: (arg: any) => any) {
   const o: any = {};
   const keys = getFieldNames == null ? Object.keys(self) : getFieldNames(self);

src/fable-library/Util.ts

@@ -33,10 +33,6 @@ export interface IDisposable {
   Dispose(): void;
 }
 
-export interface IStringable {
-  ToString(): void;
-}
-
 export interface IComparer<T> {
   Compare(x: T, y: T): number;
 }
@@ -108,16 +104,12 @@ export function isDisposable<T>(x: T | IDisposable): x is IDisposable {
   return x != null && typeof (x as IDisposable).Dispose === "function";
 }
 
-export function isStringable<T>(x: T | IStringable): x is IStringable {
-  return x != null && typeof (x as IStringable).ToString === "function";
-}
-
 export function sameConstructor(x: any, y: any) {
   return Object.getPrototypeOf(x).constructor === Object.getPrototypeOf(y).constructor;
 }
 
 export function isUnionLike(x: any) {
-  return x != null && x.tag != null && x.fields != null && typeof x.cases === "function";
+  return x != null && typeof x.tag === "number" && Array.isArray(x.fields) && typeof x.cases === "function";
 }
 
 export class Comparer<T> implements IComparer<T> {

src/quicktest/QuickTest.fs

@@ -53,10 +53,10 @@ let testCaseAsync msg f =
                     printfn "%s" ex.StackTrace
         } |> Async.StartImmediate)
 
-let measureTime (f: unit -> unit) = emitJsStatement f """
+let measureTime (f: unit -> unit) = emitJsStatement () """
     //js
     const startTime = process.hrtime();
-    $0();
+    f();
     const elapsed = process.hrtime(startTime);
     console.log("Ms:", elapsed[0] * 1e3 + elapsed[1] / 1e6);
     //!js
@@ -66,19 +66,3 @@ let measureTime (f: unit -> unit) = emitJsStatement f """
 // to Fable.Tests project. For example:
 // testCase "Addition works" <| fun () ->
 //     2 + 2 |> equal 4
-
-type MyGetter =
-    abstract Foo: int
-    abstract MyNumber: int
-
-measureTime <| (fun () ->
-    let myGetter = { new MyGetter with
-                        member _.Foo = 1
-                        member this.MyNumber = this.Foo + 1 }
-
-    let mutable x = 0
-    for i = 0 to 1000000000 do
-        x <- x + myGetter.MyNumber
-
-    printfn "x = %i" x
-)