Support eval and exec mode in wasm

- Expose `pyEval`, `pyExec`, `pyExecSingle` in wasm module

wasm/demo/src/main.js

@@ -36,7 +36,7 @@ function runCodeFromTextarea() {
 
     const code = editor.getValue();
     try {
-        rp.pyEval(code, {
+        rp.pyExec(code, {
             stdout: output => {
                 const shouldScroll =
                     consoleElement.scrollHeight - consoleElement.scrollTop ===

wasm/lib/src/lib.rs

@@ -8,11 +8,13 @@ extern crate futures;
 extern crate js_sys;
 #[macro_use]
 extern crate rustpython_vm;
+extern crate rustpython_compiler;
 extern crate wasm_bindgen;
 extern crate wasm_bindgen_futures;
 extern crate web_sys;
 
 use js_sys::{Object, Reflect, TypeError};
+use rustpython_compiler::compile::Mode;
 use std::panic;
 use wasm_bindgen::prelude::*;
 
@@ -47,25 +49,8 @@ pub fn setup_console_error() {
 #[wasm_bindgen(typescript_custom_section)]
 const TS_CMT_START: &'static str = "/*";
 
-#[wasm_bindgen(js_name = pyEval)]
-/// Evaluate Python code
-///
-/// ```js
-/// pyEval(code, options?);
-/// ```
-///
-/// `code`: `string`: The Python code to run
-///
-/// `options`:
-///
-/// -   `vars?`: `{ [key: string]: any }`: Variables passed to the VM that can be
-///     accessed in Python with the variable `js_vars`. Functions do work, and
-///     receive the Python kwargs as the `this` argument.
-/// -   `stdout?`: `"console" | ((out: string) => void) | null`: A function to replace the
-///     native print native print function, and it will be `console.log` when giving
-///     `undefined` or "console", and it will be a dumb function when giving null.
-
-pub fn eval_py(source: &str, options: Option<Object>) -> Result<JsValue, JsValue> {
+fn run_py(source: &str, options: Option<Object>, mode: Mode) -> Result<JsValue, JsValue> {
+    let vm = VMStore::init(PY_EVAL_VM_ID.into(), Some(true));
     let options = options.unwrap_or_else(Object::new);
     let js_vars = {
         let prop = Reflect::get(&options, &"vars".into())?;
@@ -77,15 +62,62 @@ pub fn eval_py(source: &str, options: Option<Object>) -> Result<JsValue, JsValue
             return Err(TypeError::new("vars must be an object").into());
         }
     };
-    let vm = VMStore::init(PY_EVAL_VM_ID.into(), Some(true));
 
     vm.set_stdout(Reflect::get(&options, &"stdout".into())?)?;
 
     if let Some(js_vars) = js_vars {
         vm.add_to_scope("js_vars".into(), js_vars.into())?;
     }
+    vm.run(source, mode)
+}
+#[wasm_bindgen(js_name = pyEval)]
+/// Evaluate Python code
+///
+/// ```js
+/// var result = pyEval(code, options?);
+/// ```
+///
+/// `code`: `string`: The Python code to run in eval mode
+///
+/// `options`:
+///
+/// -   `vars?`: `{ [key: string]: any }`: Variables passed to the VM that can be
+///     accessed in Python with the variable `js_vars`. Functions do work, and
+///     receive the Python kwargs as the `this` argument.
+/// -   `stdout?`: `"console" | ((out: string) => void) | null`: A function to replace the
+///     native print native print function, and it will be `console.log` when giving
+///     `undefined` or "console", and it will be a dumb function when giving null.
 
-    vm.exec(source)
+pub fn eval_py(source: &str, options: Option<Object>) -> Result<JsValue, JsValue> {
+    run_py(source, options, Mode::Eval)
+}
+
+#[wasm_bindgen(js_name = pyExec)]
+/// Evaluate Python code
+///
+/// ```js
+/// pyExec(code, options?);
+/// ```
+///
+/// `code`: `string`: The Python code to run in exec mode
+///
+/// `options`: The options are the same as eval mode
+pub fn exec_py(source: &str, options: Option<Object>) {
+    let _ = run_py(source, options, Mode::Exec);
+}
+
+#[wasm_bindgen(js_name = pyExecSingle)]
+/// Evaluate Python code
+///
+/// ```js
+/// var result = pyExecSingle(code, options?);
+/// ```
+///
+/// `code`: `string`: The Python code to run in exec single mode
+///
+/// `options`: The options are the same as eval mode
+pub fn exec_single_py(source: &str, options: Option<Object>) -> Result<JsValue, JsValue> {
+    run_py(source, options, Mode::Single)
 }
 
 #[wasm_bindgen(typescript_custom_section)]

wasm/lib/src/vm_class.rs

@@ -278,7 +278,7 @@ impl WASMVirtualMachine {
         })?
     }
 
-    fn run(&self, source: &str, mode: compile::Mode) -> Result<JsValue, JsValue> {
+    pub(crate) fn run(&self, source: &str, mode: compile::Mode) -> Result<JsValue, JsValue> {
         self.assert_valid()?;
         self.with_unchecked(
             |StoredVirtualMachine {

wasm/tests/test_exec_mode.py

@@ -0,0 +1,46 @@
+import time
+import sys
+
+from selenium import webdriver
+from selenium.webdriver.firefox.options import Options
+import pytest
+
+def print_stack(driver):
+    stack = driver.execute_script(
+        "return window.__RUSTPYTHON_ERROR_MSG + '\\n' + window.__RUSTPYTHON_ERROR_STACK"
+    )
+    print(f"RustPython error stack:\n{stack}", file=sys.stderr)
+
+
+@pytest.fixture(scope="module")
+def driver(request):
+    options = Options()
+    options.add_argument('-headless')
+    driver = webdriver.Firefox(options=options)
+    try:
+        driver.get("http://localhost:8080")
+    except Exception as e:
+        print_stack(driver)
+        raise
+    time.sleep(5)
+    yield driver
+    driver.close()
+
+
+def test_eval_mode(driver):
+    assert driver.execute_script("return window.rp.pyEval('1+1')") == 2
+
+def test_exec_mode(driver):
+    assert driver.execute_script("return window.rp.pyExec('1+1')") is None
+
+def test_exec_single_mode(driver):
+    assert driver.execute_script("return window.rp.pyExecSingle('1+1')") == 2
+    assert driver.execute_script(
+        """
+        var output = [];
+        save_output = function(text) {{
+            output.push(text)
+        }};
+        window.rp.pyExecSingle('1+1\\n2+2',{stdout: save_output});
+        return output;
+        """) == ['2\n', '4\n']