add

ccxt/static_dependencies/ethereum/utils/functional.py

@@ -0,0 +1,75 @@
+import collections
+import functools
+import itertools
+from typing import (  # noqa: F401
+    Any,
+    Callable,
+    Dict,
+    Iterable,
+    List,
+    Mapping,
+    Set,
+    Tuple,
+    TypeVar,
+    Union,
+)
+
+from .toolz import (
+    compose as _compose,
+)
+
+T = TypeVar("T")
+
+
+def identity(value: T) -> T:
+    return value
+
+
+TGIn = TypeVar("TGIn")
+TGOut = TypeVar("TGOut")
+TFOut = TypeVar("TFOut")
+
+
+def combine(
+    f: Callable[[TGOut], TFOut], g: Callable[[TGIn], TGOut]
+) -> Callable[[TGIn], TFOut]:
+    return lambda x: f(g(x))
+
+
+def apply_to_return_value(
+    callback: Callable[..., T]
+) -> Callable[..., Callable[..., T]]:
+    def outer(fn: Callable[..., T]) -> Callable[..., T]:
+        # We would need to type annotate *args and **kwargs but doing so segfaults
+        # the PyPy builds. We ignore instead.
+        @functools.wraps(fn)
+        def inner(*args, **kwargs) -> T:  # type: ignore
+            return callback(fn(*args, **kwargs))
+
+        return inner
+
+    return outer
+
+
+TVal = TypeVar("TVal")
+TKey = TypeVar("TKey")
+to_tuple = apply_to_return_value(
+    tuple
+)  # type: Callable[[Callable[..., Iterable[TVal]]], Callable[..., Tuple[TVal, ...]]]  # noqa: E501
+to_list = apply_to_return_value(
+    list
+)  # type: Callable[[Callable[..., Iterable[TVal]]], Callable[..., List[TVal]]]  # noqa: E501
+to_set = apply_to_return_value(
+    set
+)  # type: Callable[[Callable[..., Iterable[TVal]]], Callable[..., Set[TVal]]]  # noqa: E501
+to_dict = apply_to_return_value(
+    dict
+)  # type: Callable[[Callable[..., Iterable[Union[Mapping[TKey, TVal], Tuple[TKey, TVal]]]]], Callable[..., Dict[TKey, TVal]]]  # noqa: E501
+to_ordered_dict = apply_to_return_value(
+    collections.OrderedDict
+)  # type: Callable[[Callable[..., Iterable[Union[Mapping[TKey, TVal], Tuple[TKey, TVal]]]]], Callable[..., collections.OrderedDict[TKey, TVal]]]  # noqa: E501
+sort_return = _compose(to_tuple, apply_to_return_value(sorted))
+flatten_return = _compose(
+    to_tuple, apply_to_return_value(itertools.chain.from_iterable)
+)
+reversed_return = _compose(to_tuple, apply_to_return_value(reversed), to_tuple)