Improved compatibility function reduce (stop condition)

Author: dhondta

docs/pages/helpers.md

@@ -33,6 +33,7 @@ It also defines a few utility or backward-compatibility functions.
 `ensure_str` | ensures the input, either string or bytes, is a string
 `execfile` | same function as used in Python 2
 `iterbytes` | iterates over the bytes of a string (kept for backward compatibility)
+`reduce` | similar to `functools.reduce`, but with a `condition` optional argument to define a stop condition
 `u` | dummy alias for `str` (kept for backward compatibility)
 
 !!! warning "Global scope and the `ts` module"

src/tinyscript/VERSION.txt

@@ -1 +1 @@
-1.30.8
+1.30.9

src/tinyscript/helpers/compat.py

@@ -2,9 +2,6 @@
 """Formerly common Python2/3 compatibility functions, now left for backward-compatibility.
 
 """
-from functools import reduce
-
-
 __all__ = __features__ = ["b", "binary_type", "byteindex", "execfile", "ensure_binary", "ensure_str", "iterbytes",
                           "reduce", "string_types", "text_type", "u"]
 
@@ -63,3 +60,21 @@ def iterbytes(text):
     for c in text:
         yield c
 
+
+_initial_missing = object()
+
+def reduce(function, sequence, initial=_initial_missing, stop=None):
+    """ Similar to functools.reduce, but with a stop condition.
+    reduce(function, sequence[, initial, stop]) -> value """
+    it = iter(sequence)
+    try:
+        value = next(it) if initial is _initial_missing else initial
+    except StopIteration:
+        raise TypeError("reduce() of empty sequence with no initial value") from None
+    for element in it:
+        v = function(value, element)
+        if stop and stop(v):
+            break
+        value = v
+    return value
+

tests/conftest.py

@@ -0,0 +1,12 @@
+# -*- coding: UTF-8 -*-
+import pytest
+
+from utils import remove
+
+
+@pytest.fixture(scope="session", autouse=True)
+def clear_files_teardown():
+    yield None
+    for f in [".test-script.py", ".tinyscript-test.ini", "report.pdf", "test-script.py"]:
+        remove(f)
+

tests/test_helpers_compat.py

@@ -21,4 +21,8 @@ def test_compatibility_functions(self):
         self.assertRaises(TypeError, ensure_binary, [])
         self.assertEqual(ensure_binary("test"), b("test"))
         self.assertEqual(ensure_binary(b"test"), b("test"))
+        l = (_ for _ in range(100000000))
+        self.assertRaises(TypeError, reduce, lambda x: x, [])
+        self.assertEqual(reduce(lambda a, b: a+b, l, stop=lambda x: x > 1000), 990)
+        self.assertEqual(reduce(lambda a, b: a+b, l, 20, stop=lambda x: x > 1000), 938)
 

tests/utils.py

@@ -10,8 +10,7 @@
 from os.path import dirname, exists, join
 from shutil import rmtree as shutil_rmtree
 from time import sleep
-from tinyscript.helpers.constants import WINDOWS
-from tinyscript.helpers.decorators import failsafe
+from tinyscript.helpers import failsafe, Path, WINDOWS
 from tinyscript.argreparse import ArgumentParser
 from unittest import TestCase
 try:
@@ -22,7 +21,7 @@
 
 __all__ = ["args", "dirname", "dummy_function", "dummy_lambda", "dummy_sleep", "exists", "join", "logger", "logging",
            "makedirs", "mock_patch", "remove", "rmdir", "rmtree", "sleep", "sys", "temp_stdin", "touch", "temp_stdout",
-           "tmpf", "FakeLogRecord", "FakeNamespace", "TestCase", "_FakeParserAction", "FIXTURES", "WINDOWS"]
+           "tmpf", "FakeLogRecord", "FakeNamespace", "Path", "TestCase", "_FakeParserAction", "FIXTURES", "WINDOWS"]
 
 
 FIXTURES = ArgumentParser._globals_dict = {