add python 2 support

.travis.yml

@@ -1,8 +1,16 @@
 language: python
 
 python:
+  - 2.7
+  - 3.4
+  - 3.5
   - 3.6
-  - 3.7-dev
+  - 3.7
+  - 3.8
+  - 3.9-dev
+  - nightly
+  - pypy
+  - pypy3
 install:
   - pip install .
 script:

roundrobin/basic_rr.py

@@ -1,8 +1,7 @@
 from itertools import cycle
-from typing import Any, Callable
 
 
-def basic(dataset: [Any]) -> Callable[[], Any]:
+def basic(dataset):
     iterator = cycle(dataset)
 
     def get_next():

roundrobin/basic_rr.pyi

@@ -0,0 +1,4 @@
+from typing import Any, Callable
+
+
+def basic(dataset: [Any]) -> Callable[[], Any]: ...

roundrobin/smooth_rr.py

@@ -1,11 +1,8 @@
-from typing import Callable, Optional, Tuple
-
-
-def smooth(dataset: [Tuple[str, int]]) -> Callable[[], Optional[str]]:
+def smooth(dataset):
     dataset_length = len(dataset)
     dataset_extra_weights = [ItemWeight(*x) for x in dataset]
 
-    def get_next() -> Optional[str]:
+    def get_next():
         if dataset_length == 0:
             return None
         if dataset_length == 1:
@@ -20,19 +17,15 @@ def get_next() -> Optional[str]:
                 extra.effective_weight += 1
             if not result or result.current_weight < extra.current_weight:
                 result = extra
-        if result:
-            result.current_weight -= total_weight
-            return result.key
-        return None
+        if not result:  # this should be unreachable, but check anyway
+            raise RuntimeError
+        result.current_weight -= total_weight
+        return result.key
 
     return get_next
 
 
 class ItemWeight:
-    key: str
-    weight: int
-    current_weight: int
-    effective_weight: int
 
     __slots__ = ('key', 'weight', 'current_weight', 'effective_weight')
 

roundrobin/smooth_rr.pyi

@@ -0,0 +1,12 @@
+from typing import Any, Callable, Tuple
+
+
+def smooth(dataset: [Tuple[Any, int]]) -> Callable[[], Any]:
+    def get_next() -> Any: ...
+
+
+class ItemWeight:
+    key: Any
+    weight: int
+    current_weight: int
+    effective_weight: int

roundrobin/weighted_rr.py

@@ -1,31 +1,40 @@
-import math
-from typing import Callable, Optional, Tuple
+try:
+    from math import gcd
+except ImportError:
+    from fractions import gcd
 
 
-def weighted(dataset: [Tuple[str, int]]) -> Callable[[], Optional[str]]:
-    current_index = -1
-    current_weight = 0
+# python2 workaround for python3 nonlocal keyword
+class Store:
+    __slots__ = ('index', 'weight')
+
+    def __init__(self, index, weight):
+        self.index = index
+        self.weight = weight
+
+
+def weighted(dataset):
+    current = Store(index=-1, weight=0)
+
     dataset_length = len(dataset)
     dataset_max_weight = 0
     dataset_gcd_weight = 0
 
     for _, weight in dataset:
         if dataset_max_weight < weight:
             dataset_max_weight = weight
-        dataset_gcd_weight = math.gcd(dataset_gcd_weight, weight)
+        dataset_gcd_weight = gcd(dataset_gcd_weight, weight)
 
-    def get_next() -> Optional[str]:
-        nonlocal current_index
-        nonlocal current_weight
+    def get_next():
         while True:
-            current_index = (current_index + 1) % dataset_length
-            if current_index == 0:
-                current_weight = current_weight - dataset_gcd_weight
-                if current_weight <= 0:
-                    current_weight = dataset_max_weight
-                    if current_weight == 0:
+            current.index = (current.index + 1) % dataset_length
+            if current.index == 0:
+                current.weight = current.weight - dataset_gcd_weight
+                if current.weight <= 0:
+                    current.weight = dataset_max_weight
+                    if current.weight == 0:
                         return None
-            if dataset[current_index][1] >= current_weight:
-                return dataset[current_index][0]
+            if dataset[current.index][1] >= current.weight:
+                return dataset[current.index][0]
 
     return get_next

roundrobin/weighted_rr.pyi

@@ -0,0 +1,5 @@
+from typing import Any, Callable, Tuple
+
+
+def weighted(dataset: [Tuple[Any, int]]) -> Callable[[], Any]:
+    def get_next() -> Any: ...

setup.py

@@ -1,24 +1,31 @@
-import pathlib
-
+import os
 import setuptools
 
-HERE = pathlib.Path(__file__).parent
-README = (HERE / "README.md").read_text()
+README_PATH = os.path.join(os.path.dirname(os.path.realpath(__file__)), "README.md")
+
+
+def setup():
+    readme_content = ''
+    with open(README_PATH, "r") as fp:
+        readme_content = fp.read()
+    setuptools.setup(
+        name="roundrobin",
+        version="0.0.2",
+        description="Collection of roundrobin utilities",
+        long_description=readme_content,
+        long_description_content_type="text/markdown",
+        url="https://github.com/linnik/roundrobin",
+        author="Vyacheslav Linnik",
+        author_email="[email protected]",
+        license="MIT",
+        classifiers=[
+            "License :: OSI Approved :: MIT License",
+            "Programming Language :: Python :: 2",
+            "Programming Language :: Python :: 3",
+        ],
+        packages=setuptools.find_packages(),
+    )
+
 
-setuptools.setup(
-    name="roundrobin",
-    version="0.0.1",
-    description="Collection of roundrobin utilities",
-    long_description=README,
-    long_description_content_type="text/markdown",
-    url="https://github.com/linnik/roundrobin",
-    author="Vyacheslav Linnik",
-    author_email="[email protected]",
-    license="MIT",
-    classifiers=[
-        "License :: OSI Approved :: MIT License",
-        "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.5",
-    ],
-    packages=setuptools.find_packages(),
-)
+if __name__ == "__main__":
+    setup()