Computed vars tuple and str indexing support (#1322)

reflex/vars.py

@@ -16,6 +16,7 @@ from typing import (
     List,
     Optional,
     Set,
+    Tuple,
     Type,
     Union,
     _GenericAlias,  # type: ignore
@@ -198,9 +199,9 @@ class Var(ABC):
         Raises:
             TypeError: If the var is not indexable.
         """
-        # Indexing is only supported for lists, dicts, and dataframes.
+        # Indexing is only supported for strings, lists, tuples, dicts, and dataframes.
         if not (
-            types._issubclass(self.type_, Union[List, Dict])
+            types._issubclass(self.type_, Union[List, Dict, Tuple, str])
             or types.is_dataframe(self.type_)
         ):
             if self.type_ == Any:
@@ -218,9 +219,9 @@ class Var(ABC):
         if isinstance(i, Var):
             i = BaseVar(name=i.name, type_=i.type_, state=i.state, is_local=True)
 
-        # Handle list indexing.
+        # Handle list/tuple/str indexing.
-        if types._issubclass(self.type_, List):
+        if types._issubclass(self.type_, Union[List, Tuple, str]):
-            # List indices must be ints, slices, or vars.
+            # List/Tuple/String indices must be ints, slices, or vars.
             if not isinstance(i, types.get_args(Union[int, slice, Var])):
                 raise TypeError("Index must be an integer.")
 

tests/test_var.py

@@ -1,5 +1,5 @@
 import typing
-from typing import Dict, List
+from typing import Dict, List, Tuple
 
 import cloudpickle
 import pytest
@@ -272,31 +272,51 @@ def test_basic_operations(TestObj):
     assert str(v([1, 2, 3]).length()) == "{[1, 2, 3].length}"
 
 
-def test_var_indexing_lists():
+@pytest.mark.parametrize(
-    """Test that we can index into list vars."""
+    "var",
-    lst = BaseVar(name="lst", type_=List[int])
+    [
+        BaseVar(name="list", type_=List[int]),
+        BaseVar(name="tuple", type_=Tuple[int, int]),
+        BaseVar(name="str", type_=str),
+    ],
+)
+def test_var_indexing_lists(var):
+    """Test that we can index into str, list or tuple vars.
 
+    Args:
+        var : The str, list or tuple base var.
+    """
     # Test basic indexing.
-    assert str(lst[0]) == "{lst.at(0)}"
+    assert str(var[0]) == f"{{{var.name}.at(0)}}"
-    assert str(lst[1]) == "{lst.at(1)}"
+    assert str(var[1]) == f"{{{var.name}.at(1)}}"
 
     # Test negative indexing.
-    assert str(lst[-1]) == "{lst.at(-1)}"
+    assert str(var[-1]) == f"{{{var.name}.at(-1)}}"
 
     # Test non-integer indexing raises an error.
     with pytest.raises(TypeError):
-        lst["a"]
+        var["a"]
     with pytest.raises(TypeError):
-        lst[1.5]
+        var[1.5]
 
 
-def test_var_list_slicing():
+@pytest.mark.parametrize(
-    """Test that we can slice into list vars."""
+    "var",
-    lst = BaseVar(name="lst", type_=List[int])
+    [
+        BaseVar(name="lst", type_=List[int]),
+        BaseVar(name="tuple", type_=Tuple[int, int]),
+        BaseVar(name="str", type_=str),
+    ],
+)
+def test_var_list_slicing(var):
+    """Test that we can slice into str, list or tuple vars.
 
-    assert str(lst[:1]) == "{lst.slice(0, 1)}"
+    Args:
-    assert str(lst[:1]) == "{lst.slice(0, 1)}"
+        var : The str, list or tuple base var.
-    assert str(lst[:]) == "{lst.slice(0, undefined)}"
+    """
+    assert str(var[:1]) == f"{{{var.name}.slice(0, 1)}}"
+    assert str(var[:1]) == f"{{{var.name}.slice(0, 1)}}"
+    assert str(var[:]) == f"{{{var.name}.slice(0, undefined)}}"
 
 
 def test_dict_indexing():