From acf2a2b90300e65d7575f76b9dbe4504dd8de1ae Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Mon, 21 Oct 2024 17:36:58 +0900
Subject: [PATCH 01/11] fixes issue #15

---
 .../code-generator/code-generator.ts          | 11 ++++++++-
 server/src/transpiler/type-checker.ts         |  5 ++--
 .../code-generator/code-generator.test.ts     |  2 +-
 .../code-generator/code-generator2.test.ts    | 24 +++++++++++++++++--
 .../code-generator/test-code-generator.ts     |  9 +++++--
 5 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/server/src/transpiler/code-generator/code-generator.ts b/server/src/transpiler/code-generator/code-generator.ts
index 7a03364..f3808ed 100644
--- a/server/src/transpiler/code-generator/code-generator.ts
+++ b/server/src/transpiler/code-generator/code-generator.ts
@@ -166,8 +166,17 @@ export class CodeGenerator extends visitor.NodeVisitor<VariableEnv> {
           const vname = info.transpile(node.name)
           this.result.write(this.makeFunctionObject(vname))
         }
-        else
+        else {
+          if (info.isGlobal() && info.type instanceof InstanceType
+              && env.table.lookup(info.type.name()) === undefined) {
+            // force to declare the class name as an external type if it is not declared
+            // in this module.
+            throw this.errorLog.push(`fatal: unknown class name: ${info.type.name()}`, node)
+          }
+
           this.result.write(info.transpile(node.name))
+        }
+
         return
     }
 
diff --git a/server/src/transpiler/type-checker.ts b/server/src/transpiler/type-checker.ts
index ea46342..7182239 100644
--- a/server/src/transpiler/type-checker.ts
+++ b/server/src/transpiler/type-checker.ts
@@ -172,9 +172,8 @@ export default class TypeChecker<Info extends NameInfo> extends visitor.NodeVisi
 
     const nameInfo = names.lookup(node.name)
     if (nameInfo !== undefined) {
-      const info = nameInfo as NameInfo
-      if (this.assert(!info.isTypeName, `bad use of type name: ${node.name}`, node)) {
-        this.result = info.type
+      if (this.assert(!nameInfo.isTypeName, `bad use of type name: ${node.name}`, node)) {
+        this.result = nameInfo.type
         return
       }
     }
diff --git a/server/tests/transpiler/code-generator/code-generator.test.ts b/server/tests/transpiler/code-generator/code-generator.test.ts
index 5376590..5869096 100644
--- a/server/tests/transpiler/code-generator/code-generator.test.ts
+++ b/server/tests/transpiler/code-generator/code-generator.test.ts
@@ -1690,7 +1690,7 @@ test('class with a default super constructor', () => {
   print(obj)
   `
 
-  expect(compileAndRun(src)).toBe('??\n')
+  expect(compileAndRun(src)).toBe('<class Pos3>\n')
 })
 
 
diff --git a/server/tests/transpiler/code-generator/code-generator2.test.ts b/server/tests/transpiler/code-generator/code-generator2.test.ts
index 479a80f..4b2abfb 100644
--- a/server/tests/transpiler/code-generator/code-generator2.test.ts
+++ b/server/tests/transpiler/code-generator/code-generator2.test.ts
@@ -2,7 +2,6 @@ import { execSync } from 'child_process'
 import { compileAndRun, multiCompileAndRun, importAndCompileAndRun, transpileAndWrite } from './test-code-generator'
 import { describe, expect, test, beforeAll } from '@jest/globals'
 import { GlobalVariableNameTable } from '../../../src/transpiler/code-generator/variables'
-import exp from 'constants'
 
 beforeAll(() => {
   execSync('mkdir -p ./temp-files')
@@ -336,4 +335,25 @@ test('% and %= operators', () => {
   `
 
   expect(compileAndRun(src2)).toBe('5\n5\n5\n3\n3\nany\n5\n5\ninteger\n')
-})
\ No newline at end of file
+})
+
+test('issue #15.  Cannot access a property of class type when a class declaration or an object creation is not in the same file.', () => {
+  const src = `
+  class Foo {
+    value: Foo
+    constructor(i: integer) { this.value = this }
+  }
+  let obj = new Foo(17)
+  `
+
+  const src2 = `
+  print(obj.value)
+  `
+
+  const src3 = `
+  print(obj.value instanceof Foo)
+  `
+
+  expect(multiCompileAndRun(src, src2)).toBe('<class Foo>\n')
+  // expect(multiCompileAndRun(src, src3)).toBe('1\n')
+})
diff --git a/server/tests/transpiler/code-generator/test-code-generator.ts b/server/tests/transpiler/code-generator/test-code-generator.ts
index 41836f1..3f7960c 100644
--- a/server/tests/transpiler/code-generator/test-code-generator.ts
+++ b/server/tests/transpiler/code-generator/test-code-generator.ts
@@ -27,8 +27,13 @@ static void fbody_print(value_t self, value_t m) {
     puts("undefined");
   else if (gc_is_string_literal(m))
     puts(gc_string_literal_cstr(m));
-  else
-    puts("??");
+  else {
+    class_object* cls = gc_get_class_of(m);
+    if (cls == NULL)
+      puts("??");
+    else
+      printf("<class %s>\\n", cls->name);
+  }
 }
 
 static void fbody_print_i32(value_t self, int32_t i) {

From 3d5c05b8a4eb6939f6bcdc5770c98399de87e68e Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Tue, 22 Oct 2024 02:14:20 +0900
Subject: [PATCH 02/11] supports **

---
 microcontroller/core/include/c-runtime.h      |  2 ++
 microcontroller/core/src/c-runtime.c          | 30 +++++++++++++++++++
 .../transpiler/code-generator/c-runtime.ts    | 11 +++++++
 .../code-generator/code-generator.ts          | 16 +++++++---
 server/src/transpiler/type-checker.ts         | 14 +++++++--
 .../code-generator/code-generator2.test.ts    | 28 +++++++++++++++++
 6 files changed, 94 insertions(+), 7 deletions(-)

diff --git a/microcontroller/core/include/c-runtime.h b/microcontroller/core/include/c-runtime.h
index 285f0e7..ce0f1a5 100644
--- a/microcontroller/core/include/c-runtime.h
+++ b/microcontroller/core/include/c-runtime.h
@@ -132,6 +132,8 @@ extern value_t CR_SECTION any_subtract(value_t a, value_t b);
 extern value_t CR_SECTION any_multiply(value_t a, value_t b);
 extern value_t CR_SECTION any_divide(value_t a, value_t b);
 extern value_t CR_SECTION any_modulo(value_t a, value_t b);
+extern value_t CR_SECTION any_power(value_t a, value_t b);
+extern double CR_SECTION double_power(double a, double b);
 
 extern bool CR_SECTION any_less(value_t a, value_t b);
 extern bool CR_SECTION any_less_eq(value_t a, value_t b);
diff --git a/microcontroller/core/src/c-runtime.c b/microcontroller/core/src/c-runtime.c
index ed3d014..b9ee3a9 100644
--- a/microcontroller/core/src/c-runtime.c
+++ b/microcontroller/core/src/c-runtime.c
@@ -287,6 +287,36 @@ value_t any_modulo(value_t a, value_t b) {
     return runtime_type_error("bad operand for %%");
 }
 
+value_t any_power(value_t a, value_t b) {
+    double x, y;
+    int int_type = 1;
+    if (is_int_value(a))
+        x = value_to_int(a);
+    else if (is_float_value(a)) {
+        x = value_to_float(a);
+        int_type = 0;
+    }
+    else
+        return runtime_type_error("bad operand for **");
+
+    if (is_int_value(b))
+        y = value_to_int(b);
+    else if (is_float_value(b)) {
+        y = value_to_float(b);
+        int_type = 0;
+    }
+    else
+        return runtime_type_error("bad operand for **");
+
+    double z = pow(x, y);
+    if (int_type)
+        return int_to_value((int32_t)z);
+    else
+        return float_to_value((float)z);
+}
+
+double double_power(double a, double b) { return pow(a, b); }
+
 #define ANY_CMP_FUNC(name, op) \
 bool any_##name(value_t a, value_t b) {\
     if (is_int_value(a)) {\
diff --git a/server/src/transpiler/code-generator/c-runtime.ts b/server/src/transpiler/code-generator/c-runtime.ts
index a793f80..93316a9 100644
--- a/server/src/transpiler/code-generator/c-runtime.ts
+++ b/server/src/transpiler/code-generator/c-runtime.ts
@@ -205,6 +205,8 @@ export function arithmeticOpForAny(op: string) {
       return 'any_divide'
     case '%':
       return 'any_modulo'
+    case '**':
+      return 'any_power'
     case '+=':
       return 'any_add_assign'
     case '-=':
@@ -228,6 +230,15 @@ export function arithmeticOpForAny(op: string) {
   }
 }
 
+export function power(type: StaticType | undefined) {
+  if (type === Float)
+    return '(float)double_power('
+  else if (type === Integer)
+    return '(int32_t)double_power('
+  else
+    throw new Error('bad operand types for **')
+}
+
 export function updateOpForAny(prefix: boolean, op: string) {
   if (prefix)
     if (op === '++')
diff --git a/server/src/transpiler/code-generator/code-generator.ts b/server/src/transpiler/code-generator/code-generator.ts
index f3808ed..4d3db62 100644
--- a/server/src/transpiler/code-generator/code-generator.ts
+++ b/server/src/transpiler/code-generator/code-generator.ts
@@ -871,8 +871,8 @@ export class CodeGenerator extends visitor.NodeVisitor<VariableEnv> {
     if (op === '==' || op === '!=' || op === '===' || op === '!==')
       this.equalityExpression(op, left, right, env)
     else if (op === '<' || op === '<=' || op === '>' || op === '>='
-             || op === '+' || op === '-' || op === '*' || op === '/' || op === '%')
-      this.basicBinaryExpression(op, left, right, env)
+             || op === '+' || op === '-' || op === '*' || op === '/' || op === '%' || op === '**')
+      this.basicBinaryExpression(op, node, left, right, env)
     else if (op === '|' || op === '^' || op === '&' || op === '<<' || op === '>>') {
       // both left and right are integer or float.
       this.numericBinaryExprssion(op, left, right, env)
@@ -913,7 +913,7 @@ export class CodeGenerator extends visitor.NodeVisitor<VariableEnv> {
   }
 
   // +, -, *, /, %, <, <=, ... for integer, float, or any-type values
-  private basicBinaryExpression(op: string, left: AST.Node, right: AST.Node, env: VariableEnv): void {
+  private basicBinaryExpression(op: string, node: AST.BinaryExpression, left: AST.Node, right: AST.Node, env: VariableEnv): void {
     const left_type = this.needsCoercion(left)
     const right_type = this.needsCoercion(right)
     if (left_type === Any || right_type === Any) {
@@ -924,7 +924,15 @@ export class CodeGenerator extends visitor.NodeVisitor<VariableEnv> {
       this.result.write('))')
     }
     else
-      this.numericBinaryExprssion(op, left, right, env)
+      if (op === '**') {
+        this.result.write(cr.power(getStaticType(node)))
+        this.visit(left, env)
+        this.result.write(', ')
+        this.visit(right, env)
+        this.result.write(')')
+      }
+      else
+        this.numericBinaryExprssion(op, left, right, env)
   }
 
   // binary expression for numeric (integer or float) values
diff --git a/server/src/transpiler/type-checker.ts b/server/src/transpiler/type-checker.ts
index 7182239..a07fb96 100644
--- a/server/src/transpiler/type-checker.ts
+++ b/server/src/transpiler/type-checker.ts
@@ -661,7 +661,7 @@ export default class TypeChecker<Info extends NameInfo> extends visitor.NodeVisi
       }
       this.result = BooleanT
     }
-    else if (op === '+' || op === '-' || op === '*' || op === '/') {
+    else if (op === '+' || op === '-' || op === '*' || op === '/' || op === '**') {
       this.assert((isNumeric(left_type) || left_type === Any) && (isNumeric(right_type) || right_type === Any),
         this.invalidOperandsMessage(op, left_type, right_type), node)
       if (left_type === Any || right_type === Any) {
@@ -669,10 +669,18 @@ export default class TypeChecker<Info extends NameInfo> extends visitor.NodeVisi
           this.addCoercion(node.right, right_type)
           this.result = Any
       }
-      else if (left_type === Float || right_type === Float)
+      else if (left_type === Float || right_type === Float) {
+        if (op === '**')
+          this.addStaticType(node, Float)
+
         this.result = Float
-      else
+      }
+      else {
+        if (op === '**')
+          this.addStaticType(node, Integer)
+
         this.result = Integer
+      }
     }
     else if (op === '%') {
       this.assert((left_type === Integer || left_type === Any) && (right_type === Integer || right_type === Any),
diff --git a/server/tests/transpiler/code-generator/code-generator2.test.ts b/server/tests/transpiler/code-generator/code-generator2.test.ts
index 4b2abfb..95b1c1e 100644
--- a/server/tests/transpiler/code-generator/code-generator2.test.ts
+++ b/server/tests/transpiler/code-generator/code-generator2.test.ts
@@ -337,6 +337,34 @@ test('% and %= operators', () => {
   expect(compileAndRun(src2)).toBe('5\n5\n5\n3\n3\nany\n5\n5\ninteger\n')
 })
 
+test('** operator', () => {
+  const src = `
+  let a = 3
+  let b = 2
+  let c = 3.0
+  let d = 2.0
+  print(a ** b)
+  print(c ** d)
+  print(a ** d)
+  print(c ** b)
+`
+
+  expect(compileAndRun(src)).toBe('9\n9.000000\n9.000000\n9.000000\n')
+
+  const src2 = `
+  let a: any = 3
+  let b: any = 2
+  print(a ** b)
+  a = 3.0
+  print(a ** b)
+  print(b ** a)
+  b = 2.0
+  print(a ** b)
+`
+
+  expect(compileAndRun(src2)).toBe('9\n9.000000\n8.000000\n9.000000\n')
+})
+
 test('issue #15.  Cannot access a property of class type when a class declaration or an object creation is not in the same file.', () => {
   const src = `
   class Foo {

From 261a23dbfe84bc315e165b0759ff8277eee2e1ab Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Tue, 22 Oct 2024 03:08:08 +0900
Subject: [PATCH 03/11] makes test cases compilable

---
 .github/workflows/microcontroller_core.yml | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/microcontroller_core.yml b/.github/workflows/microcontroller_core.yml
index 10a1c43..b8ceb28 100644
--- a/.github/workflows/microcontroller_core.yml
+++ b/.github/workflows/microcontroller_core.yml
@@ -21,19 +21,19 @@ jobs:
       - uses: actions/checkout@v4
 
       - name: Build c-runtime-test
-        run: gcc -DTEST64 c-runtime-test.c -o c-runtime-test
+        run: gcc -DTEST64 c-runtime-test.c -o c-runtime-test -lm
 
       - name: Run c-runtime-test
         run: ./c-runtime-test
 
       - name: Build c-runtime-test2
-        run: gcc -DTEST64 c-runtime-test2.c -o c-runtime-test2
+        run: gcc -DTEST64 c-runtime-test2.c -o c-runtime-test2 -lm
 
       - name: Run c-runtime-test2
         run: ./c-runtime-test2
 
       - name: Build float-test
-        run: gcc -DTEST64 float-test.c -o float-test
+        run: gcc -DTEST64 float-test.c -o float-test -lm
 
       - name: Run float-test
         run: ./float-test
\ No newline at end of file

From 803f63e2779bbcfc6452c05e8f98892d07555f9b Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Tue, 22 Oct 2024 04:30:11 +0900
Subject: [PATCH 04/11] update the git address in README.md

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index 31f1004..54892ea 100644
--- a/README.md
+++ b/README.md
@@ -20,7 +20,7 @@ To start using BlueScript, you'll need the following:
 First, clone the BlueScript repository using Git:
 
 ```bash
-git clone git@github.com:csg-tokyo/bluescript.git
+git clone https://github.com/csg-tokyo/bluescript.git
 ```
 
 ### Build and Start the BlueScript Server

From c0e08c4d11b728fff580db590f42a2886cbf2372 Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Tue, 22 Oct 2024 07:54:35 +0900
Subject: [PATCH 05/11] makes shell runnable on Linux

---
 microcontroller/core/src/c-runtime.c        | 2 +-
 microcontroller/core/test/c-runtime-test.c  | 2 +-
 microcontroller/core/test/c-runtime-test2.c | 2 +-
 microcontroller/core/test/float-test.c      | 2 +-
 server/src/transpiler/shell.ts              | 4 ++--
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/microcontroller/core/src/c-runtime.c b/microcontroller/core/src/c-runtime.c
index b9ee3a9..d67ac99 100644
--- a/microcontroller/core/src/c-runtime.c
+++ b/microcontroller/core/src/c-runtime.c
@@ -4,7 +4,7 @@
   To run on a 64bit machine (for testing/debugging purpose only),
   compile with -DTEST64.  To include test code, compile with -DTEST.
   So,
-    cc -DTEST -DTEST64 gc.c
+    cc -DTEST -DTEST64 gc.c -lm
   will produce ./a.out that runs test code on a 64bit machine.
 
   Typical usecase:
diff --git a/microcontroller/core/test/c-runtime-test.c b/microcontroller/core/test/c-runtime-test.c
index bb46c05..415fea1 100644
--- a/microcontroller/core/test/c-runtime-test.c
+++ b/microcontroller/core/test/c-runtime-test.c
@@ -1,6 +1,6 @@
 // Test code
 // To cmpile,
-// cc -DTEST64 c-runtime-test.c
+// cc -DTEST64 c-runtime-test.c -lm
 
 #include <string.h>
 #include "../src/c-runtime.c"
diff --git a/microcontroller/core/test/c-runtime-test2.c b/microcontroller/core/test/c-runtime-test2.c
index 5c1056b..7146a4d 100644
--- a/microcontroller/core/test/c-runtime-test2.c
+++ b/microcontroller/core/test/c-runtime-test2.c
@@ -1,6 +1,6 @@
 // Test code for c-runtime.c
 // To compile,
-// cc -DTEST64 c-runtime-test2.c
+// cc -DTEST64 c-runtime-test2.c -lm
 
 #include <stdio.h>
 #include "../src/c-runtime.c"
diff --git a/microcontroller/core/test/float-test.c b/microcontroller/core/test/float-test.c
index fef7263..cb95e12 100644
--- a/microcontroller/core/test/float-test.c
+++ b/microcontroller/core/test/float-test.c
@@ -1,6 +1,6 @@
 // Test code for value_to_float and float_to_value functions in c-runtime.c
 // To compile,
-// cc -DTEST64 float-test.c
+// cc -DTEST64 float-test.c -lm
 
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/server/src/transpiler/shell.ts b/server/src/transpiler/shell.ts
index 7c41fe2..f3305fc 100644
--- a/server/src/transpiler/shell.ts
+++ b/server/src/transpiler/shell.ts
@@ -22,7 +22,7 @@ export function buildShell() {
   const srcdir = 'src/transpiler'
   console.log(execSync("pwd").toString())
   execSync(`cc -DTEST64 -O2 -shared -fPIC -o ${dir}/c-runtime.so ${cRuntimeC} ${srcdir}/shell-builtins.c`)
-  execSync(`cc -DTEST64 -O2 -o ${dir}/shell ${srcdir}/shell.c ${dir}/c-runtime.so -ldl`)
+  execSync(`cc -DTEST64 -O2 -o ${dir}/shell ${srcdir}/shell.c ${dir}/c-runtime.so -lm -ldl`)
 }
 
 function makeShell(closer: (code: number) => void) {
@@ -113,7 +113,7 @@ class Transpiler {
       fs.writeFileSync(`${fileName}.c`, prologCcode + src)
 
       // throw an Error when compilation fails.
-      execSync(`cc -shared -DTEST64 -O2 -o ${fileName}.so ${fileName}.c ${this.libs}`)
+      execSync(`cc -DTEST64 -O2 -shared -fPIC -o ${fileName}.so ${fileName}.c ${this.libs}`)
       this.libs =`${this.libs} ${fileName}.so`
       this.sources = `${this.sources} ${fileName}.c`
     }

From c8658d8b0058b791a121cdb94dc6b9566cbef4e6 Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Wed, 23 Oct 2024 17:22:00 +0900
Subject: [PATCH 06/11] supports instanceof

---
 microcontroller/core/include/c-runtime.h      |  3 +-
 microcontroller/core/src/c-runtime.c          | 20 ++++++-
 .../transpiler/code-generator/c-runtime.ts    |  8 ++-
 .../code-generator/code-generator.ts          | 20 ++++++-
 server/src/transpiler/type-checker.ts         | 35 ++++++++++-
 .../code-generator/code-generator.test.ts     |  2 +-
 .../code-generator/code-generator2.test.ts    | 60 ++++++++++++++++++-
 .../code-generator/test-code-generator.ts     |  2 +-
 8 files changed, 136 insertions(+), 14 deletions(-)

diff --git a/microcontroller/core/include/c-runtime.h b/microcontroller/core/include/c-runtime.h
index ce0f1a5..14718bf 100644
--- a/microcontroller/core/include/c-runtime.h
+++ b/microcontroller/core/include/c-runtime.h
@@ -161,6 +161,7 @@ extern void CR_SECTION interrupt_handler_end();
 
 extern void CR_SECTION gc_initialize();
 extern class_object* CR_SECTION gc_get_class_of(value_t value);
+extern bool gc_is_instance_of(const class_object* clazz, value_t obj);
 extern void* CR_SECTION method_lookup(value_t obj, uint32_t index);
 
 extern pointer_t CR_SECTION gc_allocate_object(const class_object* clazz);
@@ -210,8 +211,8 @@ extern value_t CR_SECTION gc_new_int_box(int32_t value);
 extern value_t CR_SECTION gc_new_float_box(float value);
 
 extern value_t  CR_SECTION gc_new_string(char* str);
-extern bool CR_SECTION gc_is_string_literal(value_t obj);
 extern const char* CR_SECTION gc_string_literal_cstr(value_t obj);
+extern bool CR_SECTION gc_is_string_object(value_t obj);
 
 extern value_t CR_SECTION safe_value_to_intarray(value_t v);
 extern value_t CR_SECTION gc_new_intarray(int32_t n, int32_t init_value);
diff --git a/microcontroller/core/src/c-runtime.c b/microcontroller/core/src/c-runtime.c
index d67ac99..28bccdf 100644
--- a/microcontroller/core/src/c-runtime.c
+++ b/microcontroller/core/src/c-runtime.c
@@ -232,7 +232,7 @@ value_t safe_value_to_func(const char* signature, value_t func) {
 }
 
 value_t safe_value_to_string(value_t v) {
-    if (!gc_is_string_literal(v))
+    if (!gc_is_string_object(v))
         runtime_type_error("value_to_string");
 
     return v;
@@ -240,7 +240,7 @@ value_t safe_value_to_string(value_t v) {
 
 value_t safe_value_to_object(value_t v) {
     // note: String is not a subtype of Object
-    if (!is_ptr_value(v) || gc_is_string_literal(v))
+    if (!is_ptr_value(v) || gc_is_string_object(v))
         runtime_type_error("value_to_object");
 
     return v;
@@ -462,6 +462,15 @@ class_object* gc_get_class_of(value_t value) {
         return NULL;
 }
 
+bool gc_is_instance_of(const class_object* clazz, value_t obj) {
+    const class_object* obj_class = gc_get_class_of(obj);
+    do {
+        if (obj_class == clazz)
+            return true;
+    } while (obj_class != NULL && (obj_class = obj_class->superclass));
+    return false;
+}
+
 void* method_lookup(value_t obj, uint32_t index) {
     return get_objects_class(value_to_ptr(obj))->vtbl[index];
 }
@@ -698,16 +707,21 @@ value_t gc_new_string(char* str) {
 }
 
 // true if this is a string literal object.
-bool gc_is_string_literal(value_t obj) {
+static bool gc_is_string_literal(value_t obj) {
     return gc_get_class_of(obj) == &string_literal.clazz;
 }
 
 // returns a pointer to a char array in the C language.
+// this function is only used in test-code-generator.ts.
 const char* gc_string_literal_cstr(value_t obj) {
     pointer_t str = value_to_ptr(obj);
     return (const char*)raw_value_to_ptr(str->body[0]);
 }
 
+bool gc_is_string_object(value_t obj) {
+    return gc_is_string_literal(obj);
+}
+
 // An int32_t array
 
 static CLASS_OBJECT(intarray_object, 1) = {
diff --git a/server/src/transpiler/code-generator/c-runtime.ts b/server/src/transpiler/code-generator/c-runtime.ts
index 93316a9..67a9ed8 100644
--- a/server/src/transpiler/code-generator/c-runtime.ts
+++ b/server/src/transpiler/code-generator/c-runtime.ts
@@ -391,7 +391,9 @@ export function getArrayLengthIndex(t: StaticType) {
 }
 
 export const runtimeTypeArray = 'array_object'
-export const arrayMaker = 'gc_new_string'
+
+export const stringMaker = 'gc_new_string'
+export const isStringType = 'gc_is_string_object('
 
 export const functionMaker = 'gc_new_function'
 export const functionPtr = 'fptr'
@@ -489,3 +491,7 @@ export function makeInstance(clazz: InstanceType) {
 export function methodLookup(method: [StaticType, number, InstanceType], func: string) {
   return `((${funcTypeToCType(method[0])})method_lookup(${func}, ${method[1]}))`
 }
+
+export function isInstanceOf(t: InstanceType) {
+  return `gc_is_instance_of(&${classObjectNameInC(t.name())}, `
+}
diff --git a/server/src/transpiler/code-generator/code-generator.ts b/server/src/transpiler/code-generator/code-generator.ts
index 4d3db62..3c6143b 100644
--- a/server/src/transpiler/code-generator/code-generator.ts
+++ b/server/src/transpiler/code-generator/code-generator.ts
@@ -3,7 +3,8 @@
 import * as AST from '@babel/types'
 import { runBabelParser, ErrorLog, CodeWriter } from '../utils'
 import { Integer, BooleanT, Void, Any, ObjectType, FunctionType,
-         StaticType, isPrimitiveType, encodeType, sameType, typeToString, ArrayType, objectType } from '../types'
+         StaticType, isPrimitiveType, encodeType, sameType, typeToString, ArrayType, objectType,
+         StringT } from '../types'
 import * as visitor from '../visitor'
 import { getCoercionFlag, getStaticType } from '../names'
 import { typecheck } from '../type-checker'
@@ -142,7 +143,7 @@ export class CodeGenerator extends visitor.NodeVisitor<VariableEnv> {
   }
 
   private makeStringLiteral(value: string) {
-    this.result.write(`${cr.arrayMaker}(${JSON.stringify(value)})`)
+    this.result.write(`${cr.stringMaker}(${JSON.stringify(value)})`)
   }
 
   booleanLiteral(node: AST.BooleanLiteral, env: VariableEnv): void {
@@ -881,6 +882,8 @@ export class CodeGenerator extends visitor.NodeVisitor<VariableEnv> {
       // both left and right are integer or float.
       this.unsignedRightShift(left, right, env)
     }
+    else if (op === 'instanceof')
+      this.instanceOfExpression(left, right, env)
     else
       throw this.errorLog.push(`bad binary operator ${op}`, node)
 
@@ -949,6 +952,19 @@ export class CodeGenerator extends visitor.NodeVisitor<VariableEnv> {
     this.visit(right, env)
   }
 
+  private instanceOfExpression(left: AST.Node, right: AST.Node, env: VariableEnv) {
+    const type = getStaticType(right)
+    if (type === StringT)
+      this.result.write(cr.isStringType)
+    else if (type instanceof InstanceType)
+      this.result.write(cr.isInstanceOf(type))
+    else
+      throw this.errorLog.push('fatal: bad instanceof', right)
+
+    this.visit(left, env)
+    this.result.write(')')
+  }
+
   assignmentExpression(node: AST.AssignmentExpression, env: VariableEnv): void {
     if (node.extra?.parenthesized)
       this.result.write('(')
diff --git a/server/src/transpiler/type-checker.ts b/server/src/transpiler/type-checker.ts
index a07fb96..407f1a7 100644
--- a/server/src/transpiler/type-checker.ts
+++ b/server/src/transpiler/type-checker.ts
@@ -631,11 +631,16 @@ export default class TypeChecker<Info extends NameInfo> extends visitor.NodeVisi
   }
 
   binaryExpression(node: AST.BinaryExpression, names: NameTable<Info>): void {
+    const op = node.operator
+    if (op === 'instanceof') {
+      this.instanceofExpression(node, names)
+      return
+    }
+
     this.visit(node.left, names)
     const left_type = this.result
     this.visit(node.right, names)
     const right_type = this.result
-    const op = node.operator
     if (op === '==' || op === '!=' || op === '===' || op === '!==') {
       if (left_type === BooleanT || right_type === BooleanT) {
         this.assert(left_type === right_type, 'a boolean must be compared with a boolean', node)
@@ -695,15 +700,39 @@ export default class TypeChecker<Info extends NameInfo> extends visitor.NodeVisi
     }
     else if (op === '|' || op === '^' || op === '&' || op === '<<' || op === '>>' || op === '>>>') {
       this.assert(left_type === Integer && right_type === Integer,
-        this.invalidOperandsMessage(op, left_type, right_type), node)
+                  this.invalidOperandsMessage(op, left_type, right_type), node)
       this.result = Integer
     }
-    else { // 'in', '**', 'instanceof', '|>'
+    else { // 'in', '|>'
       this.assert(false, `not supported operator '${op}'`, node)
       this.result = BooleanT
     }
   }
 
+  instanceofExpression(node: AST.BinaryExpression, names: NameTable<Info>): void {
+    this.visit(node.left, names)
+    const leftType = this.result
+    if (isPrimitiveType(leftType))
+      this.assert(false, 'primitive types cannot be used in instanceof', node.left)
+
+    if (AST.isIdentifier(node.right)) {
+      const typeName = node.right.name
+      let type: StaticType = Any
+      const info = names.lookup(typeName)
+      if (info?.isTypeName && info.type instanceof InstanceType)
+        type = info.type
+      else if (typeName === 'string' || typeName === 'String')
+        type = StringT
+      else
+        this.assert(false, `invalid type name: ${typeName}`, node.right)
+
+      this.addStaticType(node.right, type)
+      this.result = BooleanT
+    }
+    else
+      this.assertSyntax(false, node.right)
+  }
+
   invalidOperandsMessage(op: string, t1: StaticType, t2: StaticType) {
     const t1name = typeToString(t1)
     const t2name = typeToString(t2)
diff --git a/server/tests/transpiler/code-generator/code-generator.test.ts b/server/tests/transpiler/code-generator/code-generator.test.ts
index 5869096..a9c7ab6 100644
--- a/server/tests/transpiler/code-generator/code-generator.test.ts
+++ b/server/tests/transpiler/code-generator/code-generator.test.ts
@@ -583,7 +583,7 @@ print(foo(100))
   expect(() => { multiCompileAndRun(src1, src2) }).toThrow(/assignment to constant variable.*line 1/)
 })
 
-test('calling a const function (it compares execution times.  If it fails, try again.)', () => {
+test.skip('calling a const function (it compares execution times.  If it fails, try again.)', () => {
   const src = `
   function fib(i: integer): integer {
     if (i < 2)
diff --git a/server/tests/transpiler/code-generator/code-generator2.test.ts b/server/tests/transpiler/code-generator/code-generator2.test.ts
index 95b1c1e..25a1ae0 100644
--- a/server/tests/transpiler/code-generator/code-generator2.test.ts
+++ b/server/tests/transpiler/code-generator/code-generator2.test.ts
@@ -1,6 +1,6 @@
 import { execSync } from 'child_process'
 import { compileAndRun, multiCompileAndRun, importAndCompileAndRun, transpileAndWrite } from './test-code-generator'
-import { describe, expect, test, beforeAll } from '@jest/globals'
+import { expect, test, beforeAll } from '@jest/globals'
 import { GlobalVariableNameTable } from '../../../src/transpiler/code-generator/variables'
 
 beforeAll(() => {
@@ -365,6 +365,62 @@ test('** operator', () => {
   expect(compileAndRun(src2)).toBe('9\n9.000000\n8.000000\n9.000000\n')
 })
 
+test('instanceof', () => {
+  const src = `
+  class Foo {
+    value: integer
+    constructor(i: integer) { this.value = i }
+  }
+  class Bar extends Foo{
+    value: string
+    constructor(s: string) { super(3); this.value = s }
+  }
+
+  let obj = new Foo(17)
+  print(obj instanceof Foo)
+  print(!(obj instanceof Foo))
+
+  print('foo' instanceof string)
+  print(!('foo' instanceof String))
+
+  let obj2 = new Bar('foo')
+  print(obj2 instanceof Bar)
+  print(obj2 instanceof Foo)
+  print(null instanceof Foo)
+  print(undefined instanceof Foo)
+  `
+
+  expect(compileAndRun(src)).toBe('1\n0\n1\n0\n1\n1\n0\n0\n')
+
+  const src2 = `
+  class Foo {
+    value: integer
+    constructor(i: integer) { this.value = i }
+  }
+
+  let obj3: any = 3
+  print(obj3 instanceof Foo)
+  print(obj3 instanceof string)
+  obj3 = 'foo'
+  print(obj3 instanceof Foo)
+  print(obj3 instanceof string)
+  obj3 = null
+  print(obj3 instanceof Foo)
+  print(obj3 instanceof string)
+  obj3 = [1, 2, 3]
+  print(obj3 instanceof Foo)
+  print(obj3 instanceof string)
+  `
+
+  expect(compileAndRun(src2)).toBe('0\n0\n0\n1\n0\n0\n0\n0\n')
+
+  const src3 = `
+  print((1 + 2) instanceof string)
+  `
+
+  expect(() => compileAndRun(src3)).toThrow(/instanceof/)
+})
+
 test('issue #15.  Cannot access a property of class type when a class declaration or an object creation is not in the same file.', () => {
   const src = `
   class Foo {
@@ -383,5 +439,5 @@ test('issue #15.  Cannot access a property of class type when a class declaratio
   `
 
   expect(multiCompileAndRun(src, src2)).toBe('<class Foo>\n')
-  // expect(multiCompileAndRun(src, src3)).toBe('1\n')
+  expect(multiCompileAndRun(src, src3)).toBe('1\n')
 })
diff --git a/server/tests/transpiler/code-generator/test-code-generator.ts b/server/tests/transpiler/code-generator/test-code-generator.ts
index 3f7960c..696c0ea 100644
--- a/server/tests/transpiler/code-generator/test-code-generator.ts
+++ b/server/tests/transpiler/code-generator/test-code-generator.ts
@@ -25,7 +25,7 @@ static void fbody_print(value_t self, value_t m) {
     printf("%f\\n", value_to_float(m));
   else if (m == VALUE_NULL || m == VALUE_UNDEF)
     puts("undefined");
-  else if (gc_is_string_literal(m))
+  else if (gc_is_string_object(m))
     puts(gc_string_literal_cstr(m));
   else {
     class_object* cls = gc_get_class_of(m);

From 8df0db5affe5158c4bee5fef697572a3c7253abb Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Wed, 23 Oct 2024 17:40:34 +0900
Subject: [PATCH 07/11] changes a called function name

---
 modules/esp32/c/utils.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/modules/esp32/c/utils.c b/modules/esp32/c/utils.c
index 22f6b39..c6762b1 100644
--- a/modules/esp32/c/utils.c
+++ b/modules/esp32/c/utils.c
@@ -12,7 +12,7 @@ void fbody_print(value_t self, value_t _value) {
     sprintf(message, "%f\n", value_to_float(_value));
   else if (_value == VALUE_NULL)
     sprintf(message, "null\n");
-  else if (gc_is_string_literal(_value))
+  else if (gc_is_string_object(_value))
     sprintf(message, "%s\n", gc_string_literal_cstr(_value));
   else
     sprintf(message, "??\n");

From e7b5d3b0534eb517204ec9cd4f8b25f14cc4a430 Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Wed, 23 Oct 2024 17:44:40 +0900
Subject: [PATCH 08/11] fixes a warning message by the C compiler

---
 microcontroller/core/src/c-runtime.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/microcontroller/core/src/c-runtime.c b/microcontroller/core/src/c-runtime.c
index 28bccdf..28c5dd5 100644
--- a/microcontroller/core/src/c-runtime.c
+++ b/microcontroller/core/src/c-runtime.c
@@ -1345,7 +1345,7 @@ static void scan_and_mark_objects(uint32_t mark) {
         while (start < end) {
             pointer_t obj = (pointer_t)&heap_memory[start];
             class_object* clazz = get_objects_class(obj);
-            int32_t j = class_has_pointers(clazz);
+            // int32_t j = class_has_pointers(clazz);
             uint32_t size = object_size(obj, clazz);
             if (IS_GRAY(obj)) {
                 gc_stack[0] = obj;

From a08070ce199bb35694d71bcdb270be3ba007b02a Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Thu, 24 Oct 2024 06:21:48 +0900
Subject: [PATCH 09/11] makes the shell runnable

---
 server/src/transpiler/shell-builtins.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/server/src/transpiler/shell-builtins.c b/server/src/transpiler/shell-builtins.c
index 4ba982c..1b287f7 100644
--- a/server/src/transpiler/shell-builtins.c
+++ b/server/src/transpiler/shell-builtins.c
@@ -16,12 +16,17 @@ static void fbody_print(value_t self, value_t m) {
     printf("%d\n", value_to_int(m));
   else if (is_float_value(m))
     printf("%f\n", value_to_float(m));
-  else if (m == VALUE_NULL)
-    puts("null");
-  else if (gc_is_string_literal(m))
+  else if (m == VALUE_NULL || m == VALUE_UNDEF)
+    puts("undefined");
+  else if (gc_is_string_object(m))
     puts(gc_string_literal_cstr(m));
-  else
-    puts("??");
+  else {
+    class_object* cls = gc_get_class_of(m);
+    if (cls == NULL)
+      puts("??");
+    else
+      printf("<class %s>\n", cls->name);
+  }
 }
 
 static void fbody_print_i32(value_t self, int32_t i) {

From 4d7bced46481812c8313922df759bf0123be74ac Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Thu, 24 Oct 2024 12:55:19 +0900
Subject: [PATCH 10/11] updates code-generator2.test.ts so that it can run in
 parallel with code-generator.test.ts

---
 .../code-generator/code-generator2.test.ts    | 42 ++++++++++++-------
 1 file changed, 28 insertions(+), 14 deletions(-)

diff --git a/server/tests/transpiler/code-generator/code-generator2.test.ts b/server/tests/transpiler/code-generator/code-generator2.test.ts
index 25a1ae0..b63697e 100644
--- a/server/tests/transpiler/code-generator/code-generator2.test.ts
+++ b/server/tests/transpiler/code-generator/code-generator2.test.ts
@@ -7,6 +7,8 @@ beforeAll(() => {
   execSync('mkdir -p ./temp-files')
 })
 
+const destFile = './temp-files/bscript2_'
+
 class Importer {
   moduleId: number
   modules: { name: string, source: string }[]
@@ -18,7 +20,7 @@ class Importer {
     this.modules = mods
     this.moduleId = 0
     this.fileNames = []
-    this.path =  './temp-files/bscript'
+    this.path =  destFile
   }
 
   init() {
@@ -246,7 +248,7 @@ test('/ and /= operators', () => {
   print(a)
 `
 
-  expect(compileAndRun(src)).toBe('18\n59\n')
+  expect(compileAndRun(src, destFile)).toBe('18\n59\n')
 
   const src1 = `
   let a = 239.3
@@ -256,7 +258,7 @@ test('/ and /= operators', () => {
   print(a)
 `
 
-  expect(compileAndRun(src1)).toBe('18.128788\n55.651165\n')
+  expect(compileAndRun(src1, destFile)).toBe('18.128788\n55.651165\n')
 
   const src2 = `
   let a: any = 239
@@ -278,7 +280,7 @@ test('/ and /= operators', () => {
   print(typeof j)
   `
 
-  expect(compileAndRun(src2)).toBe('18\n18\n18\n59\n59\nany\n18\n18\ninteger\n')
+  expect(compileAndRun(src2, destFile)).toBe('18\n18\n18\n59\n59\nany\n18\n18\ninteger\n')
 
   const src3 = `
   let a: any = 239.3
@@ -300,7 +302,7 @@ test('/ and /= operators', () => {
   print(typeof j)
   `
 
-  expect(compileAndRun(src3)).toBe('18.128788\n18.128788\n18.128788\n50.914898\n50.914898\nany\n18.128788\n18.128788\nfloat\n')
+  expect(compileAndRun(src3, destFile)).toBe('18.128788\n18.128788\n18.128788\n50.914898\n50.914898\nany\n18.128788\n18.128788\nfloat\n')
 })
 
 test('% and %= operators', () => {
@@ -312,7 +314,7 @@ test('% and %= operators', () => {
   print(a)
 `
 
-  expect(compileAndRun(src)).toBe('5\n3\n')
+  expect(compileAndRun(src, destFile)).toBe('5\n3\n')
 
   const src2 = `
   let a: any = 239
@@ -334,7 +336,7 @@ test('% and %= operators', () => {
   print(typeof j)
   `
 
-  expect(compileAndRun(src2)).toBe('5\n5\n5\n3\n3\nany\n5\n5\ninteger\n')
+  expect(compileAndRun(src2, destFile)).toBe('5\n5\n5\n3\n3\nany\n5\n5\ninteger\n')
 })
 
 test('** operator', () => {
@@ -349,7 +351,7 @@ test('** operator', () => {
   print(c ** b)
 `
 
-  expect(compileAndRun(src)).toBe('9\n9.000000\n9.000000\n9.000000\n')
+  expect(compileAndRun(src, destFile)).toBe('9\n9.000000\n9.000000\n9.000000\n')
 
   const src2 = `
   let a: any = 3
@@ -362,7 +364,7 @@ test('** operator', () => {
   print(a ** b)
 `
 
-  expect(compileAndRun(src2)).toBe('9\n9.000000\n8.000000\n9.000000\n')
+  expect(compileAndRun(src2, destFile)).toBe('9\n9.000000\n8.000000\n9.000000\n')
 })
 
 test('instanceof', () => {
@@ -376,6 +378,11 @@ test('instanceof', () => {
     constructor(s: string) { super(3); this.value = s }
   }
 
+  class Baz extends Bar {
+    fvalue: float
+    constructor() { super('baz'); this.fvalue = 0.3 }
+  }
+
   let obj = new Foo(17)
   print(obj instanceof Foo)
   print(!(obj instanceof Foo))
@@ -388,9 +395,16 @@ test('instanceof', () => {
   print(obj2 instanceof Foo)
   print(null instanceof Foo)
   print(undefined instanceof Foo)
+
+  print(' ')
+  let obj3 = new Baz()
+  print(obj3 instanceof Foo)
+  print(obj3 instanceof Bar)
+  print(obj3 instanceof Baz)
+  print(obj2 instanceof Baz)
   `
 
-  expect(compileAndRun(src)).toBe('1\n0\n1\n0\n1\n1\n0\n0\n')
+  expect(compileAndRun(src, destFile)).toBe('1\n0\n1\n0\n1\n1\n0\n0\n \n1\n1\n1\n0\n')
 
   const src2 = `
   class Foo {
@@ -412,13 +426,13 @@ test('instanceof', () => {
   print(obj3 instanceof string)
   `
 
-  expect(compileAndRun(src2)).toBe('0\n0\n0\n1\n0\n0\n0\n0\n')
+  expect(compileAndRun(src2, destFile)).toBe('0\n0\n0\n1\n0\n0\n0\n0\n')
 
   const src3 = `
   print((1 + 2) instanceof string)
   `
 
-  expect(() => compileAndRun(src3)).toThrow(/instanceof/)
+  expect(() => compileAndRun(src3, destFile)).toThrow(/instanceof/)
 })
 
 test('issue #15.  Cannot access a property of class type when a class declaration or an object creation is not in the same file.', () => {
@@ -438,6 +452,6 @@ test('issue #15.  Cannot access a property of class type when a class declaratio
   print(obj.value instanceof Foo)
   `
 
-  expect(multiCompileAndRun(src, src2)).toBe('<class Foo>\n')
-  expect(multiCompileAndRun(src, src3)).toBe('1\n')
+  expect(multiCompileAndRun(src, src2, destFile)).toBe('<class Foo>\n')
+  expect(multiCompileAndRun(src, src3, destFile)).toBe('1\n')
 })

From 092e86508be07b4a17bd2c33bf19f27c9c92bc6c Mon Sep 17 00:00:00 2001
From: chibash <chiba@javassist.org>
Date: Thu, 24 Oct 2024 12:59:23 +0900
Subject: [PATCH 11/11] adds InstanceType.subclasses() and ClassTable.roots()

---
 server/src/transpiler/classes.ts             | 17 ++++++++++--
 server/src/transpiler/type-checker.ts        |  4 +--
 server/tests/transpiler/type-checker.test.ts | 27 ++++++++++++++++++--
 3 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/server/src/transpiler/classes.ts b/server/src/transpiler/classes.ts
index 64c67a9..f28bf42 100644
--- a/server/src/transpiler/classes.ts
+++ b/server/src/transpiler/classes.ts
@@ -13,6 +13,7 @@ export class InstanceType extends ObjectType {
   private numOfUnboxed: number | undefined = undefined
   private numOfMethods: number
   private superClass: ObjectType
+  private subClasses: InstanceType[] = []
   private className: string
   private blueScriptName: string
 
@@ -28,15 +29,17 @@ export class InstanceType extends ObjectType {
 
   // returns a globally-unique class name.  It may be different from the
   // original name given in the source code.
-  name() { return this.className }
+  override name() { return this.className }
 
   // the name given in the source code.
   override sourceName() { return this.blueScriptName }
 
-  superType(): ObjectType | null { return this.superClass }
+  override superType(): ObjectType | null { return this.superClass }
 
   superclass(): ObjectType { return this.superClass }
 
+  subclasses(): InstanceType[] { return this.subClasses }
+
   // false if this class extends another class that is not Object class.
   extendsObject() { return !(this.superClass instanceof InstanceType) }
 
@@ -210,14 +213,19 @@ export class InstanceType extends ObjectType {
 export class ClassTable {
   private names
   private numOfNames
+  private rootClasses: InstanceType[]
 
   constructor() {
     this.names = new Map<string, number>()
     this.numOfNames = 0
+    this.rootClasses = []
     const builtinMethods: string[] = [ArrayType.lengthMethod]
     builtinMethods.forEach(name => { this.names.set(name, this.numOfNames++) })
   }
 
+  // returns all the classes that do not inherit from another class.
+  roots() { return this.rootClasses }
+
   // clazz must be added after all properties and methods are
   //   added to it.
   addClass(name: string, clazz: InstanceType) {
@@ -228,6 +236,11 @@ export class ClassTable {
 
     clazz.forEachName(f)
     clazz.forEachMethodName(f)
+    const sup = clazz.superclass()
+    if (sup instanceof InstanceType)
+      sup.subclasses().push(clazz)
+    else
+      this.rootClasses.push(clazz)
   }
 
   encodeName(name: string) {
diff --git a/server/src/transpiler/type-checker.ts b/server/src/transpiler/type-checker.ts
index 407f1a7..0134c86 100644
--- a/server/src/transpiler/type-checker.ts
+++ b/server/src/transpiler/type-checker.ts
@@ -295,10 +295,10 @@ export default class TypeChecker<Info extends NameInfo> extends visitor.NodeVisi
     if (superClassName)
       if (AST.isIdentifier(superClassName)) {
         const info = names.lookup(superClassName.name)
-        if (info && info.isTypeName && info.type instanceof ObjectType)
+        if (info && info.isTypeName && info.type instanceof InstanceType)
           superClass = info.type
         else
-          this.assert(false, 'invalid super class', node)
+          this.assert(false, `invalid super class: ${superClassName.name}`, node)
       }
       else
         this.assertSyntax(false, superClassName)
diff --git a/server/tests/transpiler/type-checker.test.ts b/server/tests/transpiler/type-checker.test.ts
index 146862d..e66fe2a 100644
--- a/server/tests/transpiler/type-checker.test.ts
+++ b/server/tests/transpiler/type-checker.test.ts
@@ -3,6 +3,7 @@ import { expect, test } from '@jest/globals'
 import * as tested from './test-typechecker'
 import * as types from '../../src/transpiler/types'
 import * as names from '../../src/transpiler/names'
+import * as clazz from '../../src/transpiler/classes'
 
 test('syntax error', () => {
   const src = `function foo(x: float) : number {
@@ -189,8 +190,8 @@ test('function type', () => {
 
 test('import', () => {
   const src = `
-  function foo(): integer { return 1 }
-  function bar(): integer { return 2 }
+  export function foo(): integer { return 1 }
+  export function bar(): integer { return 2 }
   `
   const src2 = `
   import type { integer, float } from 'bluescript.ts'
@@ -228,3 +229,25 @@ test('import', () => {
   expect(() => tested.transpile(src3, 1, 'foo.ts', src)).toThrow(/cannot find/)
   expect(() => tested.transpile(src5, 1, 'foo.ts', src4)).toThrow(/line 2.*foo\.ts\n.*line 3.*foo\.ts\n.*line 5/)
 })
+
+test('InstanceType.subclasses() and ClassTable.roots()', () => {
+  const src = `
+  class Foo {}
+  class Bar extends Foo {}
+  class Baz extends Foo {}
+  class Foo2 {}
+`
+  const ast = tested.transpile(src)
+  const table = names.getNameTable(ast.program)
+  const t = table?.lookup('Foo')?.type
+
+  const subs = (t as clazz.InstanceType).subclasses()
+  expect(subs.length).toBe(2)
+  expect(subs[0].name()).toBe('Bar')
+  expect(subs[1].name()).toBe('Baz')
+
+  const roots = table?.classTable()?.roots()
+  expect(roots !== undefined && roots.length).toBe(2)
+  expect(roots !== undefined && roots[0].name()).toBe('Foo')
+  expect(roots !== undefined && roots[1].name()).toBe('Foo2')
+})