TransientVector supports being called and nth

.github/workflows/pypi-release.yml

@@ -12,8 +12,8 @@ jobs:
     name: Build the distribution
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: ${{ vars.PYTHON_VERSION }}
       - name: Install Poetry
@@ -23,7 +23,7 @@ jobs:
       - name: Build Basilisp distributions
         run: poetry build
       - name: Upload build artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           path: dist/
           if-no-files-found: error

.github/workflows/run-clojure-test-suite.yml

@@ -12,14 +12,14 @@ jobs:
   run-clojure-test-suite:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
         with:
           path: basilisp
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v5
         with:
           path: clojure-test-suite
           repository: basilisp-lang/clojure-test-suite
-      - uses: actions/setup-python@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: '3.13'
       - name: Install pip and dependencies

.github/workflows/run-tests.yml

@@ -35,13 +35,13 @@ jobs:
             version: '3.14'
             tox-env: py314,py314-lint
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.version }}
       - name: Cache dependencies
         id: cache-deps
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             .tox
@@ -76,7 +76,7 @@ jobs:
           for filename in .coverage.*; do mv "$filename" "coverage/$filename.py${{ matrix.version }}"; done;
       - name: Archive code coverage results
         if: "startsWith (matrix.os, 'ubuntu')"
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: code-coverage.py${{ matrix.version }}
           path: coverage/.coverage.*
@@ -95,13 +95,13 @@ jobs:
           - version: '3.11'
             tox-env: pypy311
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: pypy${{ matrix.version }}
       - name: Cache dependencies
         id: cache-deps
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             .tox
@@ -127,7 +127,7 @@ jobs:
           mkdir coverage
           for filename in .coverage.*; do mv "$filename" "coverage/$filename.pypy${{ matrix.version }}"; done;
       - name: Archive code coverage results
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           name: code-coverage.pypy${{ matrix.version }}
           path: coverage/.coverage.*
@@ -154,13 +154,13 @@ jobs:
         version: ['3.10']
         tox-env: ['py310']
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: ${{ matrix.version }}
       - name: Cache dependencies
         id: cache-deps
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             .tox
@@ -196,13 +196,13 @@ jobs:
      - run-tests
      - run-pypy-tests
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: ${{ vars.PYTHON_VERSION }}
       - name: Cache dependencies
         id: cache-deps
-        uses: actions/cache@v4
+        uses: actions/cache@v5
         with:
           path: |
             .tox

.github/workflows/test-pypi-release.yml

@@ -12,16 +12,16 @@ jobs:
     name: Build the distribution
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
+      - uses: actions/checkout@v5
+      - uses: actions/setup-python@v6
         with:
           python-version: ${{ vars.PYTHON_VERSION }}
       - name: Install Poetry
         run: curl -sSL https://install.python-poetry.org | python3 -
       - name: Build Basilisp distributions
         run: poetry build
       - name: Upload build artifact
-        uses: actions/upload-artifact@v4
+        uses: actions/upload-artifact@v6
         with:
           path: dist/
           if-no-files-found: error

CHANGELOG.md

@@ -12,6 +12,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Changed
  * Add `test` and `tests` directories to `PYTHONPATH` automatically during `basilisp test` CLI invocations (#1069)
 
+### Fixed
+ * Fix a bug where transient vectors were not callable and did not support `nth` (#1331)
+
 ## [v0.5.0]
 ### Added
  * Added support for Python 3.14 (#1282)

src/basilisp/lang/interfaces.py

@@ -76,18 +76,28 @@ class ICounted(Sized, ABC):
     __slots__ = ()
 
 
-class IIndexed(ICounted, ABC):
-    """``IIndexed`` is a marker interface for types can be accessed by index.
+K = TypeVar("K")
+V = TypeVar("V")
+
+
+class IIndexed(ICounted, Generic[V], ABC):
+    """``IIndexed`` is an interface for types can be accessed by index.
 
     Of the builtin collections, only Vectors are ``IIndexed`` . ``IIndexed`` types
     respond ``True`` to the :lpy:fn:`indexed?` predicate.
 
     .. seealso::
 
-       :lpy:fn:`indexed?`"""
+       :lpy:fn:`indexed?`, :lpy:fn:`nth`"""
 
     __slots__ = ()
 
+    NTH_SENTINEL = object()
+
+    @abstractmethod
+    def nth(self, k: int, notfound: V | None = NTH_SENTINEL) -> V | None:  # type: ignore[assignment]
+        raise NotImplementedError()
+
 
 T_ExceptionInfo = TypeVar("T_ExceptionInfo", bound="IPersistentMap")
 
@@ -109,10 +119,6 @@ def data(self) -> T_ExceptionInfo:
         raise NotImplementedError()
 
 
-K = TypeVar("K")
-V = TypeVar("V")
-
-
 class IMapEntry(Generic[K, V], ABC):
     """``IMapEntry`` values are produced :lpy:fn:`seq` ing over any
     :py:class:`IAssociative` (such as a Basilisp map).

src/basilisp/lang/runtime.py

@@ -35,6 +35,7 @@
     IAssociative,
     IBlockingDeref,
     IDeref,
+    IIndexed,
     ILookup,
     IMapEntry,
     IPersistentCollection,
@@ -1437,39 +1438,41 @@ def _count_sized(coll: Sized):
     return len(coll)
 
 
-__nth_sentinel = object()
-
-
 @functools.singledispatch
-def nth(coll, i: int, notfound=__nth_sentinel):
+def nth(coll, i: int, notfound=IIndexed.NTH_SENTINEL):
     """Returns the ith element of coll (0-indexed), if it exists.
     None otherwise. If i is out of bounds, throws an IndexError unless
     notfound is specified."""
     raise TypeError(f"nth not supported on object of type {type(coll)}")
 
 
 @nth.register(type(None))
-def _nth_none(_: None, i: int, notfound=__nth_sentinel) -> None:
-    return notfound if notfound is not __nth_sentinel else None  # type: ignore[return-value]
+def _nth_none(_: None, i: int, notfound=IIndexed.NTH_SENTINEL) -> None:
+    return notfound if notfound is not IIndexed.NTH_SENTINEL else None  # type: ignore[return-value]
 
 
 @nth.register(Sequence)
-def _nth_sequence(coll: Sequence, i: int, notfound=__nth_sentinel):
+def _nth_sequence(coll: Sequence, i: int, notfound=IIndexed.NTH_SENTINEL):
     try:
         return coll[i]
     except IndexError as ex:
-        if notfound is not __nth_sentinel:
+        if notfound is not IIndexed.NTH_SENTINEL:
             return notfound
         raise ex
 
 
+@nth.register(IIndexed)
+def _nth_iindexed(coll: IIndexed, i: int, notfound=IIndexed.NTH_SENTINEL):
+    return coll.nth(i, notfound=notfound)
+
+
 @nth.register(ISeq)
-def _nth_iseq(coll: ISeq, i: int, notfound=__nth_sentinel):
+def _nth_iseq(coll: ISeq, i: int, notfound=IIndexed.NTH_SENTINEL):
     for j, e in enumerate(coll):
         if i == j:
             return e
 
-    if notfound is not __nth_sentinel:
+    if notfound is not IIndexed.NTH_SENTINEL:
         return notfound
 
     raise IndexError(f"Index {i} out of bounds")

src/basilisp/lang/vector.py

@@ -8,6 +8,7 @@
 
 from basilisp.lang.interfaces import (
     IEvolveableCollection,
+    IIndexed,
     ILispObject,
     IMapEntry,
     IPersistentMap,
@@ -51,6 +52,9 @@ def __eq__(self, other):
     def __len__(self):
         return len(self._inner)
 
+    def __call__(self, k: int) -> T | None:
+        return self._inner[k]
+
     def cons_transient(self, *elems: T) -> "TransientVector[T]":  # type: ignore[override]
         for elem in elems:
             self._inner.append(elem)
@@ -82,6 +86,14 @@ def val_at(self, k: int, default=None):
         except IndexError:
             return default
 
+    def nth(self, k: int, notfound=IIndexed.NTH_SENTINEL):
+        try:
+            return self._inner[k]
+        except IndexError:
+            if notfound is not IIndexed.NTH_SENTINEL:
+                return notfound
+            raise
+
     def pop_transient(self) -> "TransientVector[T]":
         if len(self) == 0:
             raise IndexError("Cannot pop an empty vector")
@@ -202,6 +214,14 @@ def val_at(self, k: int, default: T | None = None) -> T | None:
         except (IndexError, TypeError):
             return default
 
+    def nth(self, k: int, notfound=IIndexed.NTH_SENTINEL):
+        try:
+            return self._inner[k]
+        except IndexError:
+            if notfound is not IIndexed.NTH_SENTINEL:
+                return notfound
+            raise
+
     def empty(self) -> "PersistentVector[T]":
         return EMPTY.with_meta(self._meta)
 

tests/basilisp/core/test_transients.lpy

@@ -94,6 +94,16 @@
       []
       [:a :b :c]))
 
+  (testing "callable"
+    (are [v idx res] (= res ((transient v) idx))
+      [1]        0 1
+      [:a :b :c] 1 :b)
+
+    (are [v idx] (thrown? python/IndexError ((transient v) idx))
+      []         0
+      []         1
+      [:a :b :c] 4))
+
   (testing "count"
     (let [trx (volatile! (transient [:a :b :c]))]
       (is (= 3 (count @trx)))
@@ -116,11 +126,21 @@
 
   (testing "get"
     (are [x y z] (= z (get (transient x) y))
-      []         1  nil
+      []         1 nil
       [:a :b :c] 1 :b)
 
     (is (= :e (get (transient [:a :b :c]) 4 :e))))
 
+  (testing "nth"
+    (are [v idx res] (= res (nth (transient v) idx))
+      [1]        0 1
+      [:a :b :c] 1 :b)
+
+    (are [v idx] (thrown? python/IndexError (nth (transient v) idx))
+      []         0
+      []         1
+      [:a :b :c] 4))
+
   (testing "not seqable"
     (is (thrown? python/TypeError (seq (transient []))))))
 

tests/basilisp/vector_test.py

@@ -149,6 +149,44 @@ def test_val_at():
     assert "default" == vec.EMPTY.val_at("key", "default")
 
 
+@pytest.mark.parametrize(
+    "v,i", [(vec.v("a", "b"), 2), (vec.EMPTY, 0), (vec.EMPTY, 1), (vec.EMPTY, -1)]
+)
+def test_nth_invalid_index(v: vec.PersistentVector, i):
+    with pytest.raises(IndexError):
+        v.nth(i)
+
+
+@pytest.mark.parametrize(
+    "res,v,i",
+    [("a", vec.v("a"), 0), ("b", vec.v("a", "b"), 1), ("b", vec.v("a", "b"), -1)],
+)
+def test_nth(res, v: vec.PersistentVector, i: int):
+    assert res == v.nth(i)
+
+
+@pytest.mark.parametrize(
+    "res,v,i,default",
+    [
+        ("other", vec.EMPTY, -1, "other"),
+        ("other", vec.v("a"), 1, "other"),
+        ("b", vec.v("a", "b"), 1, "other"),
+        ("other", vec.v("a", "b"), 8, "other"),
+        ("b", vec.v("a", "b"), -1, "other"),
+    ],
+)
+def test_nth_default(res, v: vec.PersistentVector, i: int, default):
+    assert res == v.nth(i, notfound=default)
+
+
+def test_nth_invalid_keys():
+    with pytest.raises(TypeError):
+        vec.EMPTY.nth(keyword("key"))
+
+    with pytest.raises(TypeError):
+        vec.EMPTY.nth(keyword("blah"), "default")
+
+
 def test_peek():
     assert None is vec.v().peek()