feat: 支持 String 对象及成员方法

crates/oxide_kernel/src/builtin.rs

@@ -44,6 +44,28 @@ pub struct ErrorMethods {
     pub eval_error: *const (),
 }
 
+pub struct StringMethods {
+    pub index_of: *const (),
+    pub includes: *const (),
+    pub char_at: *const (),
+    pub char_code_at: *const (),
+    pub concat: *const (),
+    pub slice: *const (),
+    pub substring: *const (),
+    pub to_upper_case: *const (),
+    pub to_lower_case: *const (),
+    pub trim: *const (),
+    pub repeat: *const (),
+    pub pad_start: *const (),
+    pub pad_end: *const (),
+    pub starts_with: *const (),
+    pub ends_with: *const (),
+    pub split: *const (),
+    pub replace: *const (),
+    pub match_fn: *const (),
+    pub search: *const (),
+}
+
 pub struct BuiltinWorld {
     pub object_proto: P<JsObject>,
     pub array_proto: P<JsObject>,
@@ -393,6 +415,148 @@ impl BuiltinWorld {
         );
     }
 
+    pub fn bind_string_methods(
+        &self,
+        methods: &StringMethods,
+        string_forge: &StringForge,
+        shape_forge: &ShapeForge,
+    ) {
+        let proto_ptr = P::as_ptr(&self.string_proto) as *mut JsObject;
+        let proto = unsafe { &mut *proto_ptr };
+
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "indexOf",
+            methods.index_of,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "includes",
+            methods.includes,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "charAt",
+            methods.char_at,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "charCodeAt",
+            methods.char_code_at,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "concat",
+            methods.concat,
+            1,
+        );
+        let _ = Self::bind_method(proto, shape_forge, string_forge, "slice", methods.slice, 2);
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "substring",
+            methods.substring,
+            2,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "toUpperCase",
+            methods.to_upper_case,
+            0,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "toLowerCase",
+            methods.to_lower_case,
+            0,
+        );
+        let _ = Self::bind_method(proto, shape_forge, string_forge, "trim", methods.trim, 0);
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "repeat",
+            methods.repeat,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "padStart",
+            methods.pad_start,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "padEnd",
+            methods.pad_end,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "startsWith",
+            methods.starts_with,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "endsWith",
+            methods.ends_with,
+            1,
+        );
+        let _ = Self::bind_method(proto, shape_forge, string_forge, "split", methods.split, 1);
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "replace",
+            methods.replace,
+            2,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "match",
+            methods.match_fn,
+            1,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "search",
+            methods.search,
+            1,
+        );
+    }
+
     pub fn bind_method(
         proto: &mut JsObject,
         shape_forge: &ShapeForge,

crates/oxide_vm/Cargo.toml

@@ -13,6 +13,8 @@ oxide_types = { path = "../oxide_types" }
 bumpalo.workspace = true
 fast-float.workspace = true
 ryu.workspace = true
+memchr.workspace = true
+regex.workspace = true
 
 [dev-dependencies]
 proptest.workspace = true

crates/oxide_vm/src/builtins/mod.rs

@@ -2,3 +2,4 @@ pub mod array;
 pub mod error;
 pub mod global;
 pub mod object;
+pub mod string;

crates/oxide_vm/src/builtins/string.rs

@@ -0,0 +1,381 @@
+use oxide_kernel::shape_forge::EMPTY_SHAPE_ID;
+use oxide_types::object::JsObject;
+use oxide_types::value::JsValue;
+
+use crate::coercion;
+use crate::native::NativeResult;
+use crate::vm::Vm;
+use memchr::memchr;
+use regex::Regex;
+
+fn this_string(vm: &Vm, args: &[u8]) -> String {
+    coercion::to_string(vm.kernel().string_forge().as_ref(), vm.reg(args[0]))
+}
+
+fn make_string_array(vm: &mut Vm, parts: &[String]) -> JsValue {
+    let proto = vm.kernel().builtin_world().array_proto.as_ptr() as *mut JsObject;
+    let n = parts.len().min(31);
+    let arr = vm.epoch().alloc(JsObject::new_array(
+        EMPTY_SHAPE_ID,
+        JsValue::from_js_object(proto),
+        n,
+        vm.epoch().bump(),
+    ));
+    unsafe {
+        for (i, s) in parts.iter().enumerate().take(n) {
+            let sv = vm.intern(s);
+            (*arr).set_prop(i as u8, sv);
+        }
+        (*arr).set_prop_count(n as u8);
+    }
+    JsValue::from_js_object(arr)
+}
+
+fn as_string(vm: &Vm, val: JsValue) -> String {
+    coercion::to_string(vm.kernel().string_forge().as_ref(), val)
+}
+
+pub fn string_index_of(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        return Ok(JsValue::int(-1));
+    }
+    let search = as_string(vm, vm.reg(args[1]));
+    let pos = if args.len() > 2 {
+        (coercion::to_number(vm.reg(args[2]), vm.kernel().string_forge().as_ref()) as usize)
+            .min(s.len())
+    } else {
+        0
+    };
+
+    if search.is_empty() {
+        return Ok(JsValue::int(pos as i32));
+    }
+
+    let haystack = &s.as_bytes()[pos..];
+    if search.len() == 1 {
+        if let Some(idx) = memchr(search.as_bytes()[0], haystack) {
+            return Ok(JsValue::int((pos + idx) as i32));
+        }
+    } else if let Some(idx) = s[pos..].find(&search) {
+        return Ok(JsValue::int((pos + idx) as i32));
+    }
+    Ok(JsValue::int(-1))
+}
+
+pub fn string_includes(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        return Ok(JsValue::bool(false));
+    }
+    let search = as_string(vm, vm.reg(args[1]));
+    let pos = if args.len() > 2 {
+        (coercion::to_number(vm.reg(args[2]), vm.kernel().string_forge().as_ref()) as usize)
+            .min(s.len())
+    } else {
+        0
+    };
+
+    if search.is_empty() {
+        return Ok(JsValue::bool(true));
+    }
+
+    let haystack = &s.as_bytes()[pos..];
+    if search.len() == 1 {
+        Ok(JsValue::bool(
+            memchr(search.as_bytes()[0], haystack).is_some(),
+        ))
+    } else {
+        Ok(JsValue::bool(s[pos..].contains(&search)))
+    }
+}
+
+pub fn string_char_at(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        if s.is_empty() {
+            return Ok(vm.intern(""));
+        }
+        return Ok(vm.intern(&s[0..1]));
+    }
+    let idx = coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as i32;
+    if idx < 0 || idx as usize >= s.len() {
+        return Ok(vm.intern(""));
+    }
+    let ch = &s[(idx as usize)..(idx as usize + 1)];
+    Ok(vm.intern(ch))
+}
+
+pub fn string_char_code_at(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        if s.is_empty() {
+            return Ok(JsValue::float(f64::NAN));
+        }
+        return Ok(JsValue::int(s.as_bytes()[0] as i32));
+    }
+    let idx = coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as i32;
+    if idx < 0 || idx as usize >= s.len() {
+        return Ok(JsValue::float(f64::NAN));
+    }
+    Ok(JsValue::int(s.as_bytes()[idx as usize] as i32))
+}
+
+pub fn string_concat(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let mut result = this_string(vm, args);
+    let sf = vm.kernel().string_forge().as_ref();
+    for &arg_reg in args.iter().skip(1) {
+        result.push_str(&coercion::to_string(sf, vm.reg(arg_reg)));
+    }
+    Ok(vm.intern(&result))
+}
+
+pub fn string_slice(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    let n = s.len() as i32;
+    let start = if args.len() > 1 {
+        let v = coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as i32;
+        if v < 0 {
+            (n + v).max(0)
+        } else {
+            v.min(n)
+        }
+    } else {
+        0
+    };
+    let end = if args.len() > 2 {
+        let v = coercion::to_number(vm.reg(args[2]), vm.kernel().string_forge().as_ref()) as i32;
+        if v < 0 {
+            (n + v).max(0)
+        } else {
+            v.min(n)
+        }
+    } else {
+        n
+    };
+    let start = start as usize;
+    let end = end as usize;
+    let result = if start < end { &s[start..end] } else { "" };
+    Ok(vm.intern(result))
+}
+
+pub fn string_substring(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    let n = s.len() as i32;
+    let mut start = if args.len() > 1 {
+        (coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as i32)
+            .max(0)
+            .min(n)
+    } else {
+        0
+    };
+    let mut end = if args.len() > 2 {
+        (coercion::to_number(vm.reg(args[2]), vm.kernel().string_forge().as_ref()) as i32)
+            .max(0)
+            .min(n)
+    } else {
+        n
+    };
+    if start > end {
+        std::mem::swap(&mut start, &mut end);
+    }
+    let result = &s[start as usize..end as usize];
+    Ok(vm.intern(result))
+}
+
+pub fn string_to_upper_case(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    Ok(vm.intern(&s.to_uppercase()))
+}
+
+pub fn string_to_lower_case(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    Ok(vm.intern(&s.to_lowercase()))
+}
+
+pub fn string_trim(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    Ok(vm.intern(s.trim()))
+}
+
+pub fn string_repeat(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    let n = if args.len() > 1 {
+        (coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as usize)
+            .min(10000)
+    } else {
+        1
+    };
+    Ok(vm.intern(&s.repeat(n)))
+}
+
+pub fn string_pad_start(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    let target = if args.len() > 1 {
+        coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as usize
+    } else {
+        s.len()
+    };
+    let pad = if args.len() > 2 {
+        as_string(vm, vm.reg(args[2]))
+    } else {
+        " ".to_string()
+    };
+    if s.len() >= target || pad.is_empty() {
+        return Ok(vm.intern(&s));
+    }
+    let needed = target - s.len();
+    let reps = needed.div_ceil(pad.len());
+    let mut out = pad.repeat(reps);
+    out.truncate(needed);
+    out.push_str(&s);
+    Ok(vm.intern(&out))
+}
+
+pub fn string_pad_end(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    let target = if args.len() > 1 {
+        coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as usize
+    } else {
+        s.len()
+    };
+    let pad = if args.len() > 2 {
+        as_string(vm, vm.reg(args[2]))
+    } else {
+        " ".to_string()
+    };
+    if s.len() >= target || pad.is_empty() {
+        return Ok(vm.intern(&s));
+    }
+    let needed = target - s.len();
+    let reps = needed.div_ceil(pad.len());
+    let mut out = s;
+    let pad_repeated = pad.repeat(reps);
+    out.push_str(&pad_repeated[..needed]);
+    Ok(vm.intern(&out))
+}
+
+pub fn string_starts_with(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        return Ok(JsValue::bool(false));
+    }
+    let search = as_string(vm, vm.reg(args[1]));
+    let pos = if args.len() > 2 {
+        (coercion::to_number(vm.reg(args[2]), vm.kernel().string_forge().as_ref()) as usize)
+            .min(s.len())
+    } else {
+        0
+    };
+    Ok(JsValue::bool(s[pos..].starts_with(&search)))
+}
+
+pub fn string_ends_with(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        return Ok(JsValue::bool(false));
+    }
+    let search = as_string(vm, vm.reg(args[1]));
+    let end_pos = if args.len() > 2 {
+        (coercion::to_number(vm.reg(args[2]), vm.kernel().string_forge().as_ref()) as usize)
+            .min(s.len())
+    } else {
+        s.len()
+    };
+    Ok(JsValue::bool(s[..end_pos].ends_with(&search)))
+}
+
+pub fn string_split(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        let parts = vec![s.clone()];
+        return Ok(make_string_array(vm, &parts));
+    }
+    let sep = as_string(vm, vm.reg(args[1]));
+    let limit = if args.len() > 2 {
+        coercion::to_number(vm.reg(args[2]), vm.kernel().string_forge().as_ref()) as usize
+    } else {
+        usize::MAX
+    };
+
+    let parts: Vec<String>;
+    if sep.starts_with('/') && sep.len() > 2 && sep.ends_with('/') {
+        let pattern = &sep[1..sep.len() - 1];
+        if let Ok(re) = Regex::new(pattern) {
+            let raw: Vec<&str> = re.split(&s).collect();
+            parts = raw.iter().map(|p| p.to_string()).take(limit).collect();
+        } else {
+            parts = vec![s.clone()];
+        }
+    } else if sep.is_empty() {
+        parts = s.chars().map(|c| c.to_string()).take(limit).collect();
+    } else {
+        parts = s.split(&sep).map(|p| p.to_string()).take(limit).collect();
+    }
+    Ok(make_string_array(vm, &parts))
+}
+
+pub fn string_replace(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        return Ok(vm.intern(&s));
+    }
+    let pattern = as_string(vm, vm.reg(args[1]));
+    let replacement = if args.len() > 2 {
+        as_string(vm, vm.reg(args[2]))
+    } else {
+        String::new()
+    };
+
+    let result = if pattern.starts_with('/') && pattern.len() > 2 && pattern.ends_with('/') {
+        let pat = &pattern[1..pattern.len() - 1];
+        if let Ok(re) = Regex::new(pat) {
+            re.replace_all(&s, replacement.as_str()).to_string()
+        } else {
+            s.clone()
+        }
+    } else {
+        s.replacen(&pattern, &replacement, 1)
+    };
+    Ok(vm.intern(&result))
+}
+
+pub fn string_match_fn(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        return Ok(JsValue::undefined());
+    }
+    let pattern = as_string(vm, vm.reg(args[1]));
+    if pattern.starts_with('/') && pattern.len() > 2 && pattern.ends_with('/') {
+        let pat = &pattern[1..pattern.len() - 1];
+        if let Ok(re) = Regex::new(pat) {
+            let matches: Vec<String> = re.find_iter(&s).map(|m| m.as_str().to_string()).collect();
+            return Ok(make_string_array(vm, &matches));
+        }
+    } else if let Some(pos) = s.find(&pattern) {
+        return Ok(make_string_array(
+            vm,
+            &[s[pos..pos + pattern.len()].to_string()],
+        ));
+    }
+    Ok(JsValue::undefined())
+}
+
+pub fn string_search(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let s = this_string(vm, args);
+    if args.len() < 2 {
+        return Ok(JsValue::int(-1));
+    }
+    let pattern = as_string(vm, vm.reg(args[1]));
+    if pattern.starts_with('/') && pattern.len() > 2 && pattern.ends_with('/') {
+        let pat = &pattern[1..pattern.len() - 1];
+        if let Ok(re) = Regex::new(pat) {
+            if let Some(m) = re.find(&s) {
+                return Ok(JsValue::int(m.start() as i32));
+            }
+        }
+    } else if let Some(pos) = s.find(&pattern) {
+        return Ok(JsValue::int(pos as i32));
+    }
+    Ok(JsValue::int(-1))
+}

crates/oxide_vm/src/vm.rs

@@ -8,7 +8,7 @@ use oxide_compiler::opcode::{self, OpCode};
 
 use crate::coercion;
 use crate::native::NativeFn;
-use oxide_kernel::builtin::{ArrayMethods, ErrorMethods, ObjectMethods};
+use oxide_kernel::builtin::{ArrayMethods, ErrorMethods, ObjectMethods, StringMethods};
 use oxide_kernel::kernel::{KernelConfig, OxideKernel};
 use oxide_kernel::prop_forge::PropTemplate;
 use oxide_kernel::shape_forge::EMPTY_SHAPE_ID;
@@ -131,6 +131,45 @@ pub fn init_kernel_builtins(kernel: &Arc<OxideKernel>) {
     let bump3 = bumpalo::Bump::new();
     global.set_prop_expand(cur_count, err_val, &bump3);
     global.bump_generation();
+
+    let string_methods = StringMethods {
+        index_of: crate::builtins::string::string_index_of as *const (),
+        includes: crate::builtins::string::string_includes as *const (),
+        char_at: crate::builtins::string::string_char_at as *const (),
+        char_code_at: crate::builtins::string::string_char_code_at as *const (),
+        concat: crate::builtins::string::string_concat as *const (),
+        slice: crate::builtins::string::string_slice as *const (),
+        substring: crate::builtins::string::string_substring as *const (),
+        to_upper_case: crate::builtins::string::string_to_upper_case as *const (),
+        to_lower_case: crate::builtins::string::string_to_lower_case as *const (),
+        trim: crate::builtins::string::string_trim as *const (),
+        repeat: crate::builtins::string::string_repeat as *const (),
+        pad_start: crate::builtins::string::string_pad_start as *const (),
+        pad_end: crate::builtins::string::string_pad_end as *const (),
+        starts_with: crate::builtins::string::string_starts_with as *const (),
+        ends_with: crate::builtins::string::string_ends_with as *const (),
+        split: crate::builtins::string::string_split as *const (),
+        replace: crate::builtins::string::string_replace as *const (),
+        match_fn: crate::builtins::string::string_match_fn as *const (),
+        search: crate::builtins::string::string_search as *const (),
+    };
+    kernel.builtin_world().bind_string_methods(
+        &string_methods,
+        kernel.string_forge().as_ref(),
+        kernel.shape_forge().as_ref(),
+    );
+
+    let si_str = kernel.string_forge().intern("String").0;
+    let str_shape = kernel.shape_forge().make_shape(global.shape_id(), si_str);
+    let str_val = JsValue::from_js_object(
+        kernel.builtin_world().string_constructor.as_ptr() as *mut JsObject
+    );
+    let cur_count = global.prop_count();
+    global.set_shape_id(str_shape);
+    global.set_prop_count(cur_count + 1);
+    let bump4 = bumpalo::Bump::new();
+    global.set_prop_expand(cur_count, str_val, &bump4);
+    global.bump_generation();
 }
 
 impl Vm {
@@ -552,8 +591,20 @@ impl Vm {
                 }
 
                 OpCode::IC_GET_PROP => {
-                    let obj_ptr = self.regs[a].as_object_ptr() as *mut JsObject;
+                    let val = self.regs[a];
+                    let obj_ptr = val.as_object_ptr() as *mut JsObject;
                     if obj_ptr.is_null() {
+                        if val.is_string() {
+                            let proto_ptr =
+                                self.kernel.builtin_world().string_proto.as_ptr() as *mut JsObject;
+                            let proto = unsafe { &*proto_ptr };
+                            let prop_name_si = self.regs[b].as_string_index();
+                            if let Some(resolved) = self.resolve_property(proto, prop_name_si) {
+                                self.regs[a] = resolved;
+                                self.pc += 1;
+                                continue;
+                            }
+                        }
                         return Err("IC_GET_PROP on non-object".into());
                     }
                     let obj = unsafe { &*obj_ptr };

crates/oxide_vm/tests/builtins_string_tests.rs

@@ -0,0 +1,167 @@
+use oxide_compiler::compiler::Compiler;
+use oxide_types::value::JsValue;
+use oxide_vm::vm::Vm;
+
+fn eval(vm: &mut Vm, source: &str) -> Result<JsValue, String> {
+    let allocator = oxide_parser::Allocator::default();
+    let program =
+        oxide_parser::parse(&allocator, source).map_err(|e| format!("Parse error: {:?}", e))?;
+    let module = Compiler::new()
+        .compile(&program)
+        .map_err(|e| format!("Compile error: {}", e))?;
+    vm.run(&module)
+}
+
+fn to_str(vm: &Vm, val: JsValue) -> String {
+    vm.kernel()
+        .string_forge()
+        .lookup(val.as_string_index())
+        .unwrap_or_default()
+}
+
+#[test]
+fn string_index_of_found() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.indexOf('e')").unwrap();
+    assert_eq!(result.as_int(), 1);
+}
+
+#[test]
+fn string_index_of_not_found() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.indexOf('x')").unwrap();
+    assert_eq!(result.as_int(), -1);
+}
+
+#[test]
+fn string_includes_true() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.includes('ell')").unwrap();
+    assert!(result.as_bool());
+}
+
+#[test]
+fn string_includes_false() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.includes('xyz')").unwrap();
+    assert!(!result.as_bool());
+}
+
+#[test]
+fn string_char_at() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'hello'.charAt(1)").unwrap();
+    assert_eq!(to_str(&vm, s), "e");
+}
+
+#[test]
+fn string_char_code_at() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.charCodeAt(0)").unwrap();
+    assert_eq!(result.as_int(), 104);
+}
+
+#[test]
+fn string_concat() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'hello'.concat(' world')").unwrap();
+    assert_eq!(to_str(&vm, s), "hello world");
+}
+
+#[test]
+fn string_slice() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'hello'.slice(1, 4)").unwrap();
+    assert_eq!(to_str(&vm, s), "ell");
+}
+
+#[test]
+fn string_substring() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'hello'.substring(0, 2)").unwrap();
+    assert_eq!(to_str(&vm, s), "he");
+}
+
+#[test]
+fn string_to_upper_case() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'hello'.toUpperCase()").unwrap();
+    assert_eq!(to_str(&vm, s), "HELLO");
+}
+
+#[test]
+fn string_to_lower_case() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'HELLO'.toLowerCase()").unwrap();
+    assert_eq!(to_str(&vm, s), "hello");
+}
+
+#[test]
+fn string_trim() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'  hi  '.trim()").unwrap();
+    assert_eq!(to_str(&vm, s), "hi");
+}
+
+#[test]
+fn string_repeat() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'abc'.repeat(3)").unwrap();
+    assert_eq!(to_str(&vm, s), "abcabcabc");
+}
+
+#[test]
+fn string_pad_start() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'5'.padStart(4, '0')").unwrap();
+    assert_eq!(to_str(&vm, s), "0005");
+}
+
+#[test]
+fn string_pad_end() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'hi'.padEnd(4)").unwrap();
+    assert_eq!(to_str(&vm, s), "hi  ");
+}
+
+#[test]
+fn string_starts_with() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.startsWith('hel')").unwrap();
+    assert!(result.as_bool());
+}
+
+#[test]
+fn string_ends_with() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.endsWith('lo')").unwrap();
+    assert!(result.as_bool());
+}
+
+#[test]
+fn string_split_comma() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'a,b,c'.split(',')").unwrap();
+    assert!(result.is_object());
+}
+
+#[test]
+fn string_replace_first() {
+    let mut vm = Vm::new();
+    let s = eval(&mut vm, "'hello'.replace('l', 'L')").unwrap();
+    assert_eq!(to_str(&vm, s), "heLlo");
+}
+
+#[test]
+fn string_search_found() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.search('ll')").unwrap();
+    assert_eq!(result.as_int(), 2);
+}
+
+#[test]
+fn string_search_not_found() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "'hello'.search('x')").unwrap();
+    assert_eq!(result.as_int(), -1);
+}