Utilities: Port js.exe on windows without repl

This commit allows building js.cpp on windows. The repl functionality is
ifdef'ed out. To decrease the number of ifdefs the code that runs the
repl on Linux was moved into one place. Some globals that are unused as
a result of that are markes maybe_unused. The following commit enables
building and testing js in cmake for windows.

Utilities/js.cpp

@@ -2,12 +2,14 @@
  * Copyright (c) 2020-2023, Andreas Kling <andreas@ladybird.org>
  * Copyright (c) 2020-2023, Linus Groh <linusg@serenityos.org>
  * Copyright (c) 2020-2022, Ali Mohammad Pur <mpfard@serenityos.org>
+ * Copyright (c) 2025, Ryszard Goc <ryszardgoc@gmail.com>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #include <AK/JsonValue.h>
 #include <AK/NeverDestroyed.h>
+#include <AK/Platform.h>
 #include <AK/StringBuilder.h>
 #include <LibCore/ArgsParser.h>
 #include <LibCore/ConfigFile.h>
@@ -26,11 +28,14 @@
 #include <LibJS/Runtime/StringPrototype.h>
 #include <LibJS/Runtime/ValueInlines.h>
 #include <LibJS/SourceTextModule.h>
-#include <LibLine/Editor.h>
 #include <LibMain/Main.h>
 #include <LibTextCodec/Decoder.h>
 #include <signal.h>
 
+#if !defined(AK_OS_WINDOWS)
+#    include <LibLine/Editor.h>
+#endif
+
 // FIXME: https://github.com/LadybirdBrowser/ladybird/issues/2412
 //    We should be able to destroy the VM on process exit.
 NeverDestroyed<RefPtr<JS::VM>> g_vm_storage;
@@ -81,9 +86,11 @@ static bool s_as_module = false;
 static bool s_print_last_result = false;
 static bool s_strip_ansi = false;
 static bool s_disable_source_location_hints = false;
+#if !defined(AK_OS_WINDOWS)
 static RefPtr<Line::Editor> s_editor;
+#endif
 static String s_history_path = String {};
-static int s_repl_line_level = 0;
+[[maybe_unused]] static int s_repl_line_level = 0;
 static bool s_keep_running_repl = true;
 static int s_exit_code = 0;
 
@@ -105,7 +112,7 @@ static ErrorOr<void> print(JS::Value value, PrintTarget target = PrintTarget::St
 }
 
 static size_t s_ctrl_c_hit_count = 0;
-static ErrorOr<String> prompt_for_level(int level)
+[[maybe_unused]] static ErrorOr<String> prompt_for_level(int level)
 {
     static StringBuilder prompt_builder;
     prompt_builder.clear();
@@ -119,79 +126,6 @@ static ErrorOr<String> prompt_for_level(int level)
     return prompt_builder.to_string();
 }
 
-static ErrorOr<String> read_next_piece()
-{
-    StringBuilder piece;
-
-    auto line_level_delta_for_next_line { 0 };
-
-    do {
-        auto line_result = s_editor->get_line(TRY(prompt_for_level(s_repl_line_level)).to_byte_string());
-
-        s_ctrl_c_hit_count = 0;
-        line_level_delta_for_next_line = 0;
-
-        if (line_result.is_error()) {
-            s_keep_running_repl = false;
-            return String {};
-        }
-
-        auto& line = line_result.value();
-        s_editor->add_to_history(line);
-
-        piece.append(line);
-        piece.append('\n');
-        auto lexer = JS::Lexer(line);
-
-        enum {
-            NotInLabelOrObjectKey,
-            InLabelOrObjectKeyIdentifier,
-            InLabelOrObjectKey
-        } label_state { NotInLabelOrObjectKey };
-
-        for (JS::Token token = lexer.next(); token.type() != JS::TokenType::Eof; token = lexer.next()) {
-            switch (token.type()) {
-            case JS::TokenType::BracketOpen:
-            case JS::TokenType::CurlyOpen:
-            case JS::TokenType::ParenOpen:
-                label_state = NotInLabelOrObjectKey;
-                s_repl_line_level++;
-                break;
-            case JS::TokenType::BracketClose:
-            case JS::TokenType::CurlyClose:
-            case JS::TokenType::ParenClose:
-                label_state = NotInLabelOrObjectKey;
-                s_repl_line_level--;
-                break;
-
-            case JS::TokenType::Identifier:
-            case JS::TokenType::StringLiteral:
-                if (label_state == NotInLabelOrObjectKey)
-                    label_state = InLabelOrObjectKeyIdentifier;
-                else
-                    label_state = NotInLabelOrObjectKey;
-                break;
-            case JS::TokenType::Colon:
-                if (label_state == InLabelOrObjectKeyIdentifier)
-                    label_state = InLabelOrObjectKey;
-                else
-                    label_state = NotInLabelOrObjectKey;
-                break;
-            default:
-                break;
-            }
-        }
-
-        if (label_state == InLabelOrObjectKey) {
-            // If there's a label or object literal key at the end of this line,
-            // prompt for more lines but do not change the line level.
-            line_level_delta_for_next_line += 1;
-        }
-    } while (s_repl_line_level + line_level_delta_for_next_line > 0);
-
-    return piece.to_string();
-}
-
 static ErrorOr<void> write_to_file(String const& path)
 {
     auto file = TRY(Core::File::open(path, Core::File::OpenMode::Write, 0666));
@@ -437,19 +371,6 @@ JS_DEFINE_NATIVE_FUNCTION(ScriptObject::print)
     return JS::js_undefined();
 }
 
-static ErrorOr<void> repl(JS::Realm& realm)
-{
-    while (s_keep_running_repl) {
-        auto const piece = TRY(read_next_piece());
-        if (Utf8View { piece }.trim(JS::whitespace_characters).is_empty())
-            continue;
-
-        g_repl_statements.append(piece);
-        TRY(parse_and_run(realm, piece, "REPL"sv));
-    }
-    return {};
-}
-
 class ReplConsoleClient final : public JS::ConsoleClient {
     GC_CELL(ReplConsoleClient, JS::ConsoleClient);
 
@@ -528,6 +449,326 @@ private:
     int m_group_stack_depth { 0 };
 };
 
+#if !defined(AK_OS_WINDOWS)
+static ErrorOr<String> read_next_piece()
+{
+    StringBuilder piece;
+
+    auto line_level_delta_for_next_line { 0 };
+
+    do {
+        auto line_result = s_editor->get_line(TRY(prompt_for_level(s_repl_line_level)).to_byte_string());
+
+        s_ctrl_c_hit_count = 0;
+        line_level_delta_for_next_line = 0;
+
+        if (line_result.is_error()) {
+            s_keep_running_repl = false;
+            return String {};
+        }
+
+        auto& line = line_result.value();
+        s_editor->add_to_history(line);
+
+        piece.append(line);
+        piece.append('\n');
+        auto lexer = JS::Lexer(line);
+
+        enum {
+            NotInLabelOrObjectKey,
+            InLabelOrObjectKeyIdentifier,
+            InLabelOrObjectKey
+        } label_state { NotInLabelOrObjectKey };
+
+        for (JS::Token token = lexer.next(); token.type() != JS::TokenType::Eof; token = lexer.next()) {
+            switch (token.type()) {
+            case JS::TokenType::BracketOpen:
+            case JS::TokenType::CurlyOpen:
+            case JS::TokenType::ParenOpen:
+                label_state = NotInLabelOrObjectKey;
+                s_repl_line_level++;
+                break;
+            case JS::TokenType::BracketClose:
+            case JS::TokenType::CurlyClose:
+            case JS::TokenType::ParenClose:
+                label_state = NotInLabelOrObjectKey;
+                s_repl_line_level--;
+                break;
+
+            case JS::TokenType::Identifier:
+            case JS::TokenType::StringLiteral:
+                if (label_state == NotInLabelOrObjectKey)
+                    label_state = InLabelOrObjectKeyIdentifier;
+                else
+                    label_state = NotInLabelOrObjectKey;
+                break;
+            case JS::TokenType::Colon:
+                if (label_state == InLabelOrObjectKeyIdentifier)
+                    label_state = InLabelOrObjectKey;
+                else
+                    label_state = NotInLabelOrObjectKey;
+                break;
+            default:
+                break;
+            }
+        }
+
+        if (label_state == InLabelOrObjectKey) {
+            // If there's a label or object literal key at the end of this line,
+            // prompt for more lines but do not change the line level.
+            line_level_delta_for_next_line += 1;
+        }
+    } while (s_repl_line_level + line_level_delta_for_next_line > 0);
+
+    return piece.to_string();
+}
+
+static ErrorOr<void> repl(JS::Realm& realm)
+{
+    while (s_keep_running_repl) {
+        auto const piece = TRY(read_next_piece());
+        if (Utf8View { piece }.trim(JS::whitespace_characters).is_empty())
+            continue;
+
+        g_repl_statements.append(piece);
+        TRY(parse_and_run(realm, piece, "REPL"sv));
+    }
+    return {};
+}
+
+static ErrorOr<int> run_repl(bool gc_on_every_allocation, bool syntax_highlight)
+{
+    s_print_last_result = true;
+
+    auto root_execution_context = JS::create_simple_execution_context<ReplObject>(*g_vm);
+    auto& realm = *root_execution_context->realm;
+
+    auto& console_object = *realm.intrinsics().console_object();
+    ReplConsoleClient console_client(console_object.console());
+    console_object.console().set_client(console_client);
+    g_vm->heap().set_should_collect_on_every_allocation(gc_on_every_allocation);
+
+    auto& global_environment = realm.global_environment();
+
+    s_editor = Line::Editor::construct();
+    s_editor->load_history(s_history_path.to_byte_string());
+
+    signal(SIGINT, [](int) {
+        if (!s_editor->is_editing())
+            exit(0);
+        s_editor->save_history(s_history_path.to_byte_string());
+    });
+
+    s_editor->register_key_input_callback(Line::ctrl('C'), [](Line::Editor& editor) -> bool {
+        if (editor.buffer_view().length() == 0 || s_ctrl_c_hit_count > 0) {
+            if (++s_ctrl_c_hit_count == 2) {
+                s_keep_running_repl = false;
+                editor.finish_edit();
+                return false;
+            }
+        }
+
+        return true;
+    });
+
+    s_editor->on_display_refresh = [syntax_highlight](Line::Editor& editor) {
+        auto stylize = [&](Line::Span span, Line::Style styles) {
+            if (syntax_highlight)
+                editor.stylize(span, styles);
+        };
+        editor.strip_styles();
+
+        size_t open_indents = s_repl_line_level;
+
+        auto line = editor.line();
+        JS::Lexer lexer(line);
+        bool indenters_starting_line = true;
+        for (JS::Token token = lexer.next(); token.type() != JS::TokenType::Eof; token = lexer.next()) {
+            auto length = Utf8View { token.value() }.length();
+            auto start = token.offset();
+            auto end = start + length;
+            if (indenters_starting_line) {
+                if (token.type() != JS::TokenType::ParenClose && token.type() != JS::TokenType::BracketClose && token.type() != JS::TokenType::CurlyClose) {
+                    indenters_starting_line = false;
+                } else {
+                    --open_indents;
+                }
+            }
+
+            switch (token.category()) {
+            case JS::TokenCategory::Invalid:
+                stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Red), Line::Style::Underline });
+                break;
+            case JS::TokenCategory::Number:
+                stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Magenta) });
+                break;
+            case JS::TokenCategory::String:
+                stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Green), Line::Style::Bold });
+                break;
+            case JS::TokenCategory::Punctuation:
+                break;
+            case JS::TokenCategory::Operator:
+                break;
+            case JS::TokenCategory::Keyword:
+                switch (token.type()) {
+                case JS::TokenType::BoolLiteral:
+                case JS::TokenType::NullLiteral:
+                    stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Yellow), Line::Style::Bold });
+                    break;
+                default:
+                    stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Blue), Line::Style::Bold });
+                    break;
+                }
+                break;
+            case JS::TokenCategory::ControlKeyword:
+                stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Cyan), Line::Style::Italic });
+                break;
+            case JS::TokenCategory::Identifier:
+                stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::White), Line::Style::Bold });
+                break;
+            default:
+                break;
+            }
+        }
+
+        editor.set_prompt(prompt_for_level(open_indents).release_value_but_fixme_should_propagate_errors().to_byte_string());
+    };
+
+    auto complete = [&realm, &global_environment](Line::Editor const& editor) -> Vector<Line::CompletionSuggestion> {
+        auto line = editor.line(editor.cursor());
+
+        JS::Lexer lexer { line };
+        enum {
+            Initial,
+            CompleteVariable,
+            CompleteNullProperty,
+            CompleteProperty,
+        } mode { Initial };
+
+        FlyString variable_name;
+        FlyString property_name;
+
+        // we're only going to complete either
+        //    - <N>
+        //        where N is part of the name of a variable
+        //    - <N>.<P>
+        //        where N is the complete name of a variable and
+        //        P is part of the name of one of its properties
+        auto js_token = lexer.next();
+        for (; js_token.type() != JS::TokenType::Eof; js_token = lexer.next()) {
+            switch (mode) {
+            case CompleteVariable:
+                switch (js_token.type()) {
+                case JS::TokenType::Period:
+                    // ...<name> <dot>
+                    mode = CompleteNullProperty;
+                    break;
+                default:
+                    // not a dot, reset back to initial
+                    mode = Initial;
+                    break;
+                }
+                break;
+            case CompleteNullProperty:
+                if (js_token.is_identifier_name()) {
+                    // ...<name> <dot> <name>
+                    mode = CompleteProperty;
+                    property_name = js_token.fly_string_value();
+                } else {
+                    mode = Initial;
+                }
+                break;
+            case CompleteProperty:
+                // something came after the property access, reset to initial
+            case Initial:
+                if (js_token.type() == JS::TokenType::Identifier) {
+                    // ...<name>...
+                    mode = CompleteVariable;
+                    variable_name = js_token.fly_string_value();
+                } else {
+                    mode = Initial;
+                }
+                break;
+            }
+        }
+
+        bool last_token_has_trivia = js_token.trivia().length() > 0;
+
+        if (mode == CompleteNullProperty) {
+            mode = CompleteProperty;
+            property_name = ""_fly_string;
+            last_token_has_trivia = false; // <name> <dot> [tab] is sensible to complete.
+        }
+
+        if (mode == Initial || last_token_has_trivia)
+            return {}; // we do not know how to complete this
+
+        Vector<Line::CompletionSuggestion> results;
+
+        Function<void(JS::Shape const&, StringView)> list_all_properties = [&results, &list_all_properties](JS::Shape const& shape, auto property_pattern) {
+            for (auto const& descriptor : shape.property_table()) {
+                if (!descriptor.key.is_string())
+                    continue;
+                auto key = descriptor.key.as_string();
+                if (key.bytes_as_string_view().starts_with(property_pattern)) {
+                    Line::CompletionSuggestion completion { key, Line::CompletionSuggestion::ForSearch };
+                    if (!results.contains_slow(completion)) { // hide duplicates
+                        results.append(key.to_string().to_byte_string());
+                        results.last().invariant_offset = property_pattern.length();
+                    }
+                }
+            }
+            if (auto const* prototype = shape.prototype()) {
+                list_all_properties(prototype->shape(), property_pattern);
+            }
+        };
+
+        switch (mode) {
+        case CompleteProperty: {
+            auto reference_or_error = g_vm->resolve_binding(variable_name, &global_environment);
+            if (reference_or_error.is_error())
+                return {};
+            auto value_or_error = reference_or_error.value().get_value(*g_vm);
+            if (value_or_error.is_error())
+                return {};
+            auto variable = value_or_error.value();
+            VERIFY(!variable.is_special_empty_value());
+
+            if (!variable.is_object())
+                break;
+
+            auto const object = MUST(variable.to_object(*g_vm));
+            auto const& shape = object->shape();
+            list_all_properties(shape, property_name);
+            break;
+        }
+        case CompleteVariable: {
+            auto const& variable = realm.global_object();
+            list_all_properties(variable.shape(), variable_name);
+
+            for (auto const& name : global_environment.declarative_record().bindings()) {
+                if (name.bytes_as_string_view().starts_with(variable_name)) {
+                    results.empend(name);
+                    results.last().invariant_offset = variable_name.bytes().size();
+                }
+            }
+
+            break;
+        }
+        default:
+            VERIFY_NOT_REACHED();
+        }
+
+        return results;
+    };
+    s_editor->on_tab_complete = move(complete);
+    TRY(repl(realm));
+    s_editor->save_history(s_history_path.to_byte_string());
+    return s_exit_code;
+}
+
+#endif
+
 ErrorOr<int> serenity_main(Main::Arguments arguments)
 {
     bool gc_on_every_allocation = false;
@@ -553,7 +794,7 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     args_parser.add_positional_argument(script_paths, "Path to script files", "scripts", Core::ArgsParser::Required::No);
     args_parser.parse(arguments);
 
-    bool syntax_highlight = !disable_syntax_highlight;
+    [[maybe_unused]] bool syntax_highlight = !disable_syntax_highlight;
 
     AK::set_debug_enabled(!disable_debug_printing);
     s_history_path = TRY(String::formatted("{}/.js-history", Core::StandardPaths::home_directory()));
@@ -584,232 +825,12 @@ ErrorOr<int> serenity_main(Main::Arguments arguments)
     // FIXME: Figure out some way to interrupt the interpreter now that vm.exception() is gone.
 
     if (evaluate_script.is_empty() && script_paths.is_empty()) {
-        s_print_last_result = true;
-
-        auto root_execution_context = JS::create_simple_execution_context<ReplObject>(*g_vm);
-        auto& realm = *root_execution_context->realm;
-
-        auto& console_object = *realm.intrinsics().console_object();
-        ReplConsoleClient console_client(console_object.console());
-        console_object.console().set_client(console_client);
-        g_vm->heap().set_should_collect_on_every_allocation(gc_on_every_allocation);
-
-        auto& global_environment = realm.global_environment();
-
-        s_editor = Line::Editor::construct();
-        s_editor->load_history(s_history_path.to_byte_string());
-
-        signal(SIGINT, [](int) {
-            if (!s_editor->is_editing())
-                exit(0);
-            s_editor->save_history(s_history_path.to_byte_string());
-        });
-
-        s_editor->register_key_input_callback(Line::ctrl('C'), [](Line::Editor& editor) -> bool {
-            if (editor.buffer_view().length() == 0 || s_ctrl_c_hit_count > 0) {
-                if (++s_ctrl_c_hit_count == 2) {
-                    s_keep_running_repl = false;
-                    editor.finish_edit();
-                    return false;
-                }
-            }
-
-            return true;
-        });
-
-        s_editor->on_display_refresh = [syntax_highlight](Line::Editor& editor) {
-            auto stylize = [&](Line::Span span, Line::Style styles) {
-                if (syntax_highlight)
-                    editor.stylize(span, styles);
-            };
-            editor.strip_styles();
-
-            size_t open_indents = s_repl_line_level;
-
-            auto line = editor.line();
-            JS::Lexer lexer(line);
-            bool indenters_starting_line = true;
-            for (JS::Token token = lexer.next(); token.type() != JS::TokenType::Eof; token = lexer.next()) {
-                auto length = Utf8View { token.value() }.length();
-                auto start = token.offset();
-                auto end = start + length;
-                if (indenters_starting_line) {
-                    if (token.type() != JS::TokenType::ParenClose && token.type() != JS::TokenType::BracketClose && token.type() != JS::TokenType::CurlyClose) {
-                        indenters_starting_line = false;
-                    } else {
-                        --open_indents;
-                    }
-                }
-
-                switch (token.category()) {
-                case JS::TokenCategory::Invalid:
-                    stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Red), Line::Style::Underline });
-                    break;
-                case JS::TokenCategory::Number:
-                    stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Magenta) });
-                    break;
-                case JS::TokenCategory::String:
-                    stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Green), Line::Style::Bold });
-                    break;
-                case JS::TokenCategory::Punctuation:
-                    break;
-                case JS::TokenCategory::Operator:
-                    break;
-                case JS::TokenCategory::Keyword:
-                    switch (token.type()) {
-                    case JS::TokenType::BoolLiteral:
-                    case JS::TokenType::NullLiteral:
-                        stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Yellow), Line::Style::Bold });
-                        break;
-                    default:
-                        stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Blue), Line::Style::Bold });
-                        break;
-                    }
-                    break;
-                case JS::TokenCategory::ControlKeyword:
-                    stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::Cyan), Line::Style::Italic });
-                    break;
-                case JS::TokenCategory::Identifier:
-                    stylize({ start, end, Line::Span::CodepointOriented }, { Line::Style::Foreground(Line::Style::XtermColor::White), Line::Style::Bold });
-                    break;
-                default:
-                    break;
-                }
-            }
-
-            editor.set_prompt(prompt_for_level(open_indents).release_value_but_fixme_should_propagate_errors().to_byte_string());
-        };
-
-        auto complete = [&realm, &global_environment](Line::Editor const& editor) -> Vector<Line::CompletionSuggestion> {
-            auto line = editor.line(editor.cursor());
-
-            JS::Lexer lexer { line };
-            enum {
-                Initial,
-                CompleteVariable,
-                CompleteNullProperty,
-                CompleteProperty,
-            } mode { Initial };
-
-            FlyString variable_name;
-            FlyString property_name;
-
-            // we're only going to complete either
-            //    - <N>
-            //        where N is part of the name of a variable
-            //    - <N>.<P>
-            //        where N is the complete name of a variable and
-            //        P is part of the name of one of its properties
-            auto js_token = lexer.next();
-            for (; js_token.type() != JS::TokenType::Eof; js_token = lexer.next()) {
-                switch (mode) {
-                case CompleteVariable:
-                    switch (js_token.type()) {
-                    case JS::TokenType::Period:
-                        // ...<name> <dot>
-                        mode = CompleteNullProperty;
-                        break;
-                    default:
-                        // not a dot, reset back to initial
-                        mode = Initial;
-                        break;
-                    }
-                    break;
-                case CompleteNullProperty:
-                    if (js_token.is_identifier_name()) {
-                        // ...<name> <dot> <name>
-                        mode = CompleteProperty;
-                        property_name = js_token.fly_string_value();
-                    } else {
-                        mode = Initial;
-                    }
-                    break;
-                case CompleteProperty:
-                    // something came after the property access, reset to initial
-                case Initial:
-                    if (js_token.type() == JS::TokenType::Identifier) {
-                        // ...<name>...
-                        mode = CompleteVariable;
-                        variable_name = js_token.fly_string_value();
-                    } else {
-                        mode = Initial;
-                    }
-                    break;
-                }
-            }
-
-            bool last_token_has_trivia = js_token.trivia().length() > 0;
-
-            if (mode == CompleteNullProperty) {
-                mode = CompleteProperty;
-                property_name = ""_fly_string;
-                last_token_has_trivia = false; // <name> <dot> [tab] is sensible to complete.
-            }
-
-            if (mode == Initial || last_token_has_trivia)
-                return {}; // we do not know how to complete this
-
-            Vector<Line::CompletionSuggestion> results;
-
-            Function<void(JS::Shape const&, StringView)> list_all_properties = [&results, &list_all_properties](JS::Shape const& shape, auto property_pattern) {
-                for (auto const& descriptor : shape.property_table()) {
-                    if (!descriptor.key.is_string())
-                        continue;
-                    auto key = descriptor.key.as_string();
-                    if (key.bytes_as_string_view().starts_with(property_pattern)) {
-                        Line::CompletionSuggestion completion { key, Line::CompletionSuggestion::ForSearch };
-                        if (!results.contains_slow(completion)) { // hide duplicates
-                            results.append(key.to_string().to_byte_string());
-                            results.last().invariant_offset = property_pattern.length();
-                        }
-                    }
-                }
-                if (auto const* prototype = shape.prototype()) {
-                    list_all_properties(prototype->shape(), property_pattern);
-                }
-            };
-
-            switch (mode) {
-            case CompleteProperty: {
-                auto reference_or_error = g_vm->resolve_binding(variable_name, &global_environment);
-                if (reference_or_error.is_error())
-                    return {};
-                auto value_or_error = reference_or_error.value().get_value(*g_vm);
-                if (value_or_error.is_error())
-                    return {};
-                auto variable = value_or_error.value();
-                VERIFY(!variable.is_special_empty_value());
-
-                if (!variable.is_object())
-                    break;
-
-                auto const object = MUST(variable.to_object(*g_vm));
-                auto const& shape = object->shape();
-                list_all_properties(shape, property_name);
-                break;
-            }
-            case CompleteVariable: {
-                auto const& variable = realm.global_object();
-                list_all_properties(variable.shape(), variable_name);
-
-                for (auto const& name : global_environment.declarative_record().bindings()) {
-                    if (name.bytes_as_string_view().starts_with(variable_name)) {
-                        results.empend(name);
-                        results.last().invariant_offset = variable_name.bytes().size();
-                    }
-                }
-
-                break;
-            }
-            default:
-                VERIFY_NOT_REACHED();
-            }
-
-            return results;
-        };
-        s_editor->on_tab_complete = move(complete);
-        TRY(repl(realm));
-        s_editor->save_history(s_history_path.to_byte_string());
+#if defined(AK_OS_WINDOWS)
+        dbgln("REPL functionality is not supported on Windows");
+        VERIFY_NOT_REACHED();
+#else
+        return run_repl(gc_on_every_allocation, syntax_highlight);
+#endif
     } else {
         OwnPtr<JS::ExecutionContext> root_execution_context;
         if (use_test262_global)