str

streamable/functions.py

@@ -106,7 +106,7 @@ def map(
     iterator: Iterator[T],
     concurrency: int = 1,
     ordered: bool = True,
-    via: Literal["thread", "process"] = "thread",
+    via: "Literal['thread', 'process']" = "thread",
 ) -> Iterator[U]:
     validate_iterator(iterator)
     validate_concurrency(concurrency)

streamable/iters.py

@@ -418,7 +418,7 @@ def __init__(
         concurrency: int,
         buffer_size: int,
         ordered: bool,
-        via: Literal["thread", "process"],
+        via: "Literal['thread', 'process']",
     ) -> None:
         super().__init__(iterator, buffer_size, ordered)
         self.transformation = transformation

streamable/stream.py

@@ -1,3 +1,4 @@
+from contextlib import suppress
 import datetime
 import logging
 from multiprocessing import get_logger
@@ -11,7 +12,6 @@
     Iterable,
     Iterator,
     List,
-    Literal,
     Optional,
     Sequence,
     Set,
@@ -22,6 +22,9 @@
     overload,
 )
 
+with suppress(ImportError):
+    from typing import Literal
+
 from streamable.util.constants import NO_REPLACEMENT
 from streamable.util.validationtools import (
     validate_concurrency,
@@ -237,7 +240,7 @@ def foreach(
         effect: Callable[[T], Any],
         concurrency: int = 1,
         ordered: bool = True,
-        via: Literal["thread", "process"] = "thread",
+        via: "Literal['thread', 'process']" = "thread",
     ) -> "Stream[T]":
         """
         For each upstream element, yields it after having called `effect` on it.
@@ -247,7 +250,7 @@ def foreach(
             effect (Callable[[T], Any]): The function to be applied to each element as a side effect.
             concurrency (int): Represents both the number of threads used to concurrently apply the `effect` and the size of the buffer containing not-yet-yielded elements. If the buffer is full, the iteration over the upstream is stopped until some elements are yielded out of the buffer. (default is 1, meaning no multithreading).
             ordered (bool): If `concurrency` > 1, whether to preserve the order of upstream elements or to yield them as soon as they are processed (default preserves order).
-            via (Literal["thread", "process"]): If `concurrency` > 1, whether to apply `transformation` using processes or threads (default via threads).
+            via ("thread" or "process"): If `concurrency` > 1, whether to apply `transformation` using processes or threads (default via threads).
         Returns:
             Stream[T]: A stream of upstream elements, unchanged.
         """
@@ -305,7 +308,7 @@ def map(
         transformation: Callable[[T], U],
         concurrency: int = 1,
         ordered: bool = True,
-        via: Literal["thread", "process"] = "thread",
+        via: "Literal['thread', 'process']" = "thread",
     ) -> "Stream[U]":
         """
         Applies `transformation` on upstream elements and yields the results.
@@ -314,7 +317,7 @@ def map(
             transformation (Callable[[T], R]): The function to be applied to each element.
             concurrency (int): Represents both the number of threads used to concurrently apply `transformation` and the size of the buffer containing not-yet-yielded results. If the buffer is full, the iteration over the upstream is stopped until some results are yielded out of the buffer. (default is 1, meaning no multithreading).
             ordered (bool): If `concurrency` > 1, whether to preserve the order of upstream elements or to yield them as soon as they are processed (default preserves order).
-            via (Literal["thread", "process"]): If `concurrency` > 1, whether to apply `transformation` using processes or threads (default via threads).
+            via ("thread" or "process"): If `concurrency` > 1, whether to apply `transformation` using processes or threads (default via threads).
         Returns:
             Stream[R]: A stream of transformed elements.
         """
@@ -468,7 +471,7 @@ def __init__(
         effect: Callable[[T], Any],
         concurrency: int,
         ordered: bool,
-        via: Literal["thread", "process"],
+        via: "Literal['thread', 'process']",
     ) -> None:
         super().__init__(upstream)
         self._effect = effect
@@ -521,7 +524,7 @@ def __init__(
         transformation: Callable[[T], U],
         concurrency: int,
         ordered: bool,
-        via: Literal["thread", "process"],
+        via: "Literal['thread', 'process']",
     ) -> None:
         super().__init__(upstream)
         self._transformation = transformation