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Userland/JS: Extend the global object when using a REPL

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When we enter a repl we call initialize_global_object on our custom
ReplObject in order to expose REPL specific features. Specifically:
help(), exit(code), and load("file1.js", "file2.js", "fileEtc.js").
This commit is contained in:
Dov Alperin 2020-04-01 15:20:32 -04:00 committed by Andreas Kling
parent a0da97cb5a
commit c27e8a258a
Notes: sideshowbarker 2024-07-19 08:00:30 +09:00 
Author: https://github.com/DAlperin
Commit: https://github.com/SerenityOS/serenity/commit/c27e8a258ad
Pull-request: https://github.com/SerenityOS/serenity/pull/1567
1 changed files with 97 additions and 12 deletions
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109
Userland/js.cpp
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@ -42,6 +42,18 @@
#include <LibLine/Editor.h>
#include <stdio.h>
class ReplObject : public JS::GlobalObject {
public:
ReplObject();
virtual ~ReplObject() override;
private:
virtual const char* class_name() const override { return "ReplObject"; }
static JS::Value exit_interpreter(JS::Interpreter&);
static JS::Value repl_help(JS::Interpreter&);
static JS::Value load_file(JS::Interpreter&);
};
bool dump_ast = false;
static OwnPtr<Line::Editor> editor;
@ -169,6 +181,81 @@ static void print(JS::Value value)
putchar('\n');
}
bool file_has_shebang(AK::ByteBuffer file_contents)
{
if (file_contents.size() >= 2 && file_contents[0] == '#' && file_contents[1] == '!')
return true;
return false;
}
StringView strip_shebang(AK::ByteBuffer file_contents)
{
size_t i = 0;
for (i = 2; i < file_contents.size(); ++i) {
if (file_contents[i] == '\n')
break;
}
return StringView((const char*)file_contents.data() + i, file_contents.size() - i);
}
ReplObject::ReplObject()
{
put_native_function("exit", exit_interpreter);
put_native_function("help", repl_help);
put_native_function("load", load_file);
}
ReplObject::~ReplObject()
{
}
JS::Value ReplObject::exit_interpreter(JS::Interpreter& interpreter)
{
if (interpreter.call_frame().arguments.is_empty())
exit(0);
int exit_code = interpreter.call_frame().arguments[0].to_number().as_double();
exit(exit_code);
return JS::js_undefined();
}
JS::Value ReplObject::repl_help(JS::Interpreter& interpreter)
{
StringBuilder help_text;
help_text.append("REPL commands:\n");
help_text.append(" exit(code): exit the REPL with specified code. Defaults to 0.\n");
help_text.append(" help(): display this menu\n");
help_text.append(" load(files): Accepts file names as params to load into running session. For example repl.load(\"js/1.js\", \"js/2.js\", \"js/3.js\")\n");
String result = help_text.to_string();
return js_string(interpreter.heap(), result);
}
JS::Value ReplObject::load_file(JS::Interpreter& interpreter)
{
if (interpreter.call_frame().arguments.is_empty())
return JS::Value(false);
Vector<JS::Value> files = interpreter.call_frame().arguments;
for (JS::Value file : files) {
String file_name = file.as_string()->string();
auto js_file = Core::File::construct(file_name);
if (!js_file->open(Core::IODevice::ReadOnly)) {
fprintf(stderr, "Failed to open %s: %s\n", file_name.characters(), js_file->error_string());
}
auto file_contents = js_file->read_all();
StringView source;
if (file_has_shebang(file_contents)) {
source = strip_shebang(file_contents);
} else {
source = file_contents;
}
auto program = JS::Parser(JS::Lexer(source)).parse_program();
if (dump_ast)
program->dump(0);
auto result = interpreter.run(*program);
print(result);
}
return JS::Value(true);
}
void repl(JS::Interpreter& interpreter)
{
while (true) {
@ -198,16 +285,19 @@ int main(int argc, char** argv)
args_parser.add_positional_argument(script_path, "Path to script file", "script", Core::ArgsParser::Required::No);
args_parser.parse(argc, argv);
auto interpreter = JS::Interpreter::create<JS::GlobalObject>();
interpreter->heap().set_should_collect_on_every_allocation(gc_on_every_allocation);
interpreter->global_object().put("global", &interpreter->global_object());
if (script_path == nullptr) {
auto interpreter = JS::Interpreter::create<ReplObject>();
interpreter->heap().set_should_collect_on_every_allocation(gc_on_every_allocation);
interpreter->global_object().put("global", &interpreter->global_object());
editor = make<Line::Editor>();
editor->initialize();
repl(*interpreter);
} else {
auto interpreter = JS::Interpreter::create<JS::GlobalObject>();
interpreter->heap().set_should_collect_on_every_allocation(gc_on_every_allocation);
interpreter->global_object().put("global", &interpreter->global_object());
auto file = Core::File::construct(script_path);
if (!file->open(Core::IODevice::ReadOnly)) {
fprintf(stderr, "Failed to open %s: %s\n", script_path, file->error_string());
@ -216,13 +306,8 @@ int main(int argc, char** argv)
auto file_contents = file->read_all();
StringView source;
if (file_contents.size() >= 2 && file_contents[0] == '#' && file_contents[1] == '!') {
size_t i = 0;
for (i = 2; i < file_contents.size(); ++i) {
if (file_contents[i] == '\n')
break;
}
source = StringView((const char*)file_contents.data() + i, file_contents.size() - i);
if (file_has_shebang(file_contents)) {
source = strip_shebang(file_contents);
} else {
source = file_contents;
}