Add aeval: Asynchronous Equivalent to eval in aioconsole

aioconsole/__init__.py

@@ -3,7 +3,7 @@
 It also includes an interactive event loop, and a command line interface.
 """
 
-from .execute import aexec
+from .execute import aexec, aeval
 from .console import AsynchronousConsole, interact
 from .stream import ainput, aprint, get_standard_streams
 from .events import InteractiveEventLoop, InteractiveEventLoopPolicy
@@ -17,6 +17,7 @@
 
 __all__ = [
     "aexec",
+    "aeval",
     "ainput",
     "aprint",
     "AsynchronousConsole",

aioconsole/execute.py

@@ -148,3 +148,31 @@ async def aexec(source, local=None, stream=None, filename="<aexec>"):
         if isinstance(tree, ast.Interactive):
             exec_single_result(result, new_local, stream)
         full_update(local, new_local)
+
+
+async def aeval(source, local=None):
+    """Asynchronous equivalent to *eval*."""
+    if local is None:
+        local = {}
+
+    if not isinstance(local, dict):
+        raise TypeError("globals must be a dict")
+
+    key = "__result__"
+    # Ensure that the result key is unique within the local namespace
+    # while key in local: key += "_"
+
+    # Perform syntax check to ensure the input is a valid eval expression
+    try:
+        ast.parse(source, mode="eval")
+    except SyntaxError:
+        raise
+
+    # Assign the result of the expression to a known variable
+    wrapped_code = f"{key} = {source}"
+
+    # Use aexec to evaluate the wrapped code within the given local namespace
+    await aexec(wrapped_code, local=local)
+
+    # Return the result from the local namespace
+    return local.pop(key)

tests/test_execute.py

@@ -2,7 +2,7 @@
 import asyncio
 
 import pytest
-from aioconsole import aexec
+from aioconsole import aexec, aeval
 from aioconsole.execute import compile_for_aexec
 
 
@@ -124,3 +124,130 @@ async def test_correct():
     await aexec("async def x(): return")
     await aexec("def x(): yield")
     await aexec("async def x(): yield")
+
+
+def echo(x):
+    return x
+
+
+async def aecho(x):
+    return echo(x)
+
+
+# Parametrized test with a variety of expressions
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    "expression, local",
+    [
+        # Valid Simple Expressions
+        ("1 + 2", None),
+        ("sum([i * i for i in range(10)])", None),
+        # Invalid Expressions
+        ("def foo(): return 42", None),
+        ("x = 1", None),
+        ("x = 1\nx + 1", None),
+        ("for i in range(10): pass", None),
+        ("if True: pass", None),
+        ("while True: break", None),
+        ("try: pass\nexcept: pass", None),
+        # Expressions Involving Undefined Variables
+        ("undefined_variable", None),
+        ("undefined_function()", None),
+        # Expressions with Deliberate Errors
+        ("1/0", None),
+        ("open('nonexistent_file.txt')", None),
+        # Lambda and Anonymous Functions
+        ("(lambda x: x * 2)(5)", None),
+        # Expressions with Built-in Functions
+        ("len('test')", None),
+        ("min([3, 1, 4, 1, 5, 9])", None),
+        ("max([x * x for x in range(10)])", None),
+        # Boolean and Conditional Expressions
+        ("True and False", None),
+        ("not True", None),  # Boolean negation
+        ("5 if True else 10", None),
+        # String Manipulation
+        ("'hello' + ' ' + 'world'", None),
+        ("f'hello {42}'", None),
+        # Complex List Comprehensions
+        ("[x for x in range(5)]", None),
+        ("[x * x for x in range(10) if x % 2 == 0]", None),
+        # Expressions with Syntax Errors
+        ("return 42", None),
+        ("yield 5", None),
+        # Test with await
+        ("await aecho(5)", {"aecho": aecho, "echo": echo}),
+        # Test invalid local
+        ("...", []),
+        ("...", "string_instead_of_dict"),
+        ("...", 42),
+        ("...", set()),
+        ("...", ...),
+        ("...", 1.5),
+        ("...", object()),
+        ("...", asyncio),
+        ("...", lambda: ...),
+        ("...", {"__result__": 99}),
+        # Invalid expressions
+        ("", None),
+        (None, None),
+        (0, None),
+        ({}, None),
+        (object(), None),
+        (asyncio, None),
+        (..., None),
+        (lambda: ..., None),
+    ],
+)
+async def test_aeval(expression, local):
+    # Capture the result or exception of the synchronous eval
+    sync_exc = None
+    result = None
+    try:
+        if isinstance(expression, str):
+            sync_expression = expression.lstrip("await a")
+        else:
+            sync_expression = expression
+
+        result = eval(sync_expression, local)
+    except Exception as exc:
+        sync_exc = exc
+
+    # Capture the result or exception of the asynchronous eval
+    async_exc = None
+    async_result = None
+    try:
+        async_result = await aeval(expression, local)
+    except Exception as exc:
+        async_exc = exc
+
+    # Assert that the exceptions are of the same type
+    assert type(sync_exc) == type(async_exc)
+    # Assert that the results match
+    assert result == async_result
+
+
+# Test calling an async function without awaiting it
+@pytest.mark.asyncio
+async def test_aeval_async_func_without_await():
+    expression = "asyncio.sleep(0)"
+    local = {"asyncio": asyncio}
+    result = await aeval(expression, local)
+    assert asyncio.iscoroutine(result)
+    await result
+
+
+@pytest.mark.asyncio
+async def test_aeval_valid_await_syntax():
+    expression = "await aecho(10)"
+    local = {"aecho": aecho}
+    result = await aeval(expression, local)
+    assert result == 10
+
+
+@pytest.mark.asyncio
+async def test_aeval_coro_in_local():
+    expression = "await coro"
+    local = {"coro": aecho(10)}
+    result = await aeval(expression, local)
+    assert result == 10