Extract common functional tools to separate package.

1 files changed, 33 insertions, 0 deletions

diff --git a/functional_tools/__init__.py b/functional_tools/__init__.py
new file mode 100644
index 0000000..057bd9a
--- /dev/null
+++ b/functional_tools/__init__.py
@@ -0,0 +1,33 @@
+"""Tools to help with a more functional way of doing things."""
+from typing import Iterable
+from functools import reduce
+
+def take(iterable: Iterable, num: int) -> list:
+    """Take at most `num` items from `iterable`."""
+    iterator = iter(iterable)
+    items = []
+    try:
+        for i in range(0, num): # pylint: disable=[unused-variable]
+            items.append(next(iterator))
+
+        return items
+    except StopIteration:
+        return items
+
+def chain(value, *functions):
+    """
+    Flatten nested expressions
+
+    Inspired by, and approximates, Clojure's `->`.
+
+    Useful to rewrite nested expressions like func3(a, b, func2(c, func1(d e)))
+    into arguably flatter expressions like:
+    chain(
+      d,
+      partial(func1, e=val1),
+      partial(func2, c=val2),
+      partial(func3, a=val3, b=val3))
+
+    This can probably be improved.
+    """
+    return reduce(lambda result, func: func(result), functions, value)