Add HashTrieMap.convert, a faster way to convert to it.

Replaces manually doing things like:

    value if isinstance(value, HashTrieMap) else HashTrieMap(value)

which can cause ~2x slowdowns (and was the case also with pyrsistent)

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rpds-py"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 
 [lib]

rpds.pyi

@@ -29,6 +29,11 @@ class HashTrieMap(Mapping[KT, VT]):
     def remove(self, key: KT) -> "HashTrieMap[KT, VT]": ...
     def insert(self, key: KT, val: VT) -> "HashTrieMap[KT, VT]": ...
     def update(self, *args: Mapping): ...
+    @classmethod
+    def convert(
+        cls,
+        value: Mapping[KT, VT] | Iterable[tuple[KT, VT]],
+    ) -> "HashTrieMap[KT, VT]": ...
 
 class HashTrieSet(FrozenSet[T]):
     def __init__(self, value: Iterable[T] = ()): ...

src/lib.rs

@@ -3,7 +3,7 @@ use std::vec::IntoIter;
 
 use pyo3::exceptions::PyIndexError;
 use pyo3::pyclass::CompareOp;
-use pyo3::types::{PyDict, PyIterator, PyTuple};
+use pyo3::types::{PyDict, PyIterator, PyTuple, PyType};
 use pyo3::{exceptions::PyKeyError, types::PyMapping};
 use pyo3::{prelude::*, AsPyPointer};
 use rpds::{HashTrieMap, HashTrieSet, List};
@@ -153,6 +153,15 @@ impl HashTrieMapPy {
         }
     }
 
+    #[classmethod]
+    fn convert(_cls: &PyType, value: &PyAny, py: Python) -> PyResult<PyObject> {
+        if value.is_instance_of::<HashTrieMapPy>()? {
+            Ok(value.into())
+        } else {
+            Ok(HashTrieMapPy::extract(value)?.into_py(py))
+        }
+    }
+
     fn get(&self, key: Key) -> Option<&PyObject> {
         self.inner.get(&key)
     }

tests/test_hash_trie_map.py

@@ -298,3 +298,13 @@ def test_empty_truthiness():
 def test_iterable():
     m = HashTrieMap((i, i * 2) for i in range(3))
     assert m == HashTrieMap({0: 0, 1: 2, 2: 4})
+
+
+def test_convert_hashtriemap():
+    m = HashTrieMap({i: i * 2 for i in range(3)})
+    assert HashTrieMap.convert({i: i * 2 for i in range(3)}) == m
+
+
+def test_fast_convert_hashtriemap():
+    m = HashTrieMap({i: i * 2 for i in range(3)})
+    assert HashTrieMap.convert(m) is m