Introduced an experimental Stream API

Author: shiroyuki

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "readables-py"
-version = "0.1.7"
+version = "0.2.0"
 description = "Add readability and self-documentation to Python code"
 requires-python = ">=3.9"
 dependencies = []

readables/stream/__init__.py

@@ -0,0 +1,61 @@
+from typing import Iterable, Any, Generic, TypeVar, Callable, List, Iterator, Generator
+
+T = TypeVar('T')
+S = TypeVar('S')
+R = TypeVar('R')
+
+
+class Filter(Generic[T]):
+    def __init__(self, fn: Callable[[T], bool]):
+        self._fn = fn
+
+    def __call__(self, t: T):
+        return self._fn(t)
+
+
+class Map(Generic[S, R]):
+    def __init__(self, fn: Callable[[S], R]):
+        self._fn = fn
+
+    def __call__(self, s: S) -> R:
+        return self._fn(s)
+
+
+class FlatMap(Generic[S, R]):
+    """
+    Flat map an iterable object
+
+    While code is identical to Map, how it is used is different.
+    """
+    def __init__(self, fn: Callable[[S], R]):
+        self._fn = fn
+
+    def __call__(self, s: S) -> Generator[R, Any, None]:
+        yield self._fn(s)
+
+
+class Stream(Generic[T, S]):
+    def __init__(self, source: Iterator[T]):
+        self._source = source
+        self._chain: List[Filter | Map | FlatMap] = []
+
+    def observe(self):
+        for item in self._source:
+            included = True
+            iterated_value = item
+
+            for act in self._chain:
+                if isinstance(act, Filter) and not act(iterated_value):
+                    included = False
+                    break
+
+                if isinstance(act, Map):
+                    iterated_value = act(iterated_value)
+
+                if isinstance(act, FlatMap):
+                    raise NotImplementedError('To be implemented')
+
+            if not included:
+                continue
+
+            yield iterated_value