Fix comma separated string in "Bindings" (#797)

sandbox/darren/just_a_box.py

@@ -8,7 +8,7 @@ from textual.widgets import Static, Footer
 class JustABox(App):
     BINDINGS = [
         Binding(key="t", action="text_fade_out", description="text-opacity fade out"),
-        Binding(key="o", action="widget_fade_out", description="opacity fade out"),
+        Binding(key="o,f,w", action="widget_fade_out", description="opacity fade out"),
     ]
 
     def compose(self) -> ComposeResult:

src/textual/binding.py

@@ -1,17 +1,16 @@
 from __future__ import annotations
 
 import sys
-import rich.repr
-
 from dataclasses import dataclass
 from typing import Iterable, MutableMapping
 
+import rich.repr
+
 if sys.version_info >= (3, 10):
     from typing import TypeAlias
 else:  # pragma: no cover
     from typing_extensions import TypeAlias
 
-
 BindingType: TypeAlias = "Binding | tuple[str, str, str]"
 
 
@@ -23,7 +22,7 @@ class NoBinding(Exception):
     """A binding was not found."""
 
 
-@dataclass
+@dataclass(frozen=True)
 class Binding:
     key: str
     """Key to bind."""
@@ -47,6 +46,19 @@ class Bindings:
         def make_bindings(bindings: Iterable[BindingType]) -> Iterable[Binding]:
             for binding in bindings:
                 if isinstance(binding, Binding):
+                    binding_keys = binding.key.split(",")
+                    if len(binding_keys) > 1:
+                        for key in binding_keys:
+                            new_binding = Binding(
+                                key=key,
+                                action=binding.action,
+                                description=binding.description,
+                                show=binding.show,
+                                key_display=binding.key_display,
+                                allow_forward=binding.allow_forward,
+                            )
+                            yield new_binding
+                    else:
                         yield binding
                 else:
                     if len(binding) != 3:

tests/test_binding.py

@@ -0,0 +1,31 @@
+import pytest
+
+from textual.binding import Bindings, Binding
+
+BINDING1 = Binding("a,b", action="action1", description="description1")
+BINDING2 = Binding("c", action="action2", description="description2")
+
+
+@pytest.fixture
+def bindings():
+    yield Bindings([BINDING1, BINDING2])
+
+
+def test_bindings_get_key(bindings):
+    assert bindings.get_key("b") == Binding("b", action="action1", description="description1")
+    assert bindings.get_key("c") == BINDING2
+
+
+def test_bindings_merge_simple(bindings):
+    left = Bindings([BINDING1])
+    right = Bindings([BINDING2])
+    assert Bindings.merge([left, right]).keys == bindings.keys
+
+
+def test_bindings_merge_overlap():
+    left = Bindings([BINDING1])
+    another_binding = Binding("a", action="another_action", description="another_description")
+    assert Bindings.merge([left, Bindings([another_binding])]).keys == {
+        "a": another_binding,
+        "b": Binding("b", action="action1", description="description1"),
+    }