Add helper method to call the progress bar with only a range object a…

…nd a lambda function.

src/shogun/base/progress.h

@@ -739,5 +739,16 @@ namespace shogun
 	{
 		return PRange<T>(range, *sg_io, prefix, mode, condition);
 	}
+
+	/** Creates @ref PRange given a range that uses the global SGIO
+	 *
+	 * @param range range used
+	 * @param condition premature stopping condition
+	 */
+	template <typename T>
+	inline PRange<T> progress(Range<T> range, std::function<bool()> condition)
+	{
+		return PRange<T>(range, *sg_io, "PROGRESS: ", UTF8, condition);
+	}
 };
 #endif /* __SG_PROGRESS_H__ */

tests/unit/base/PRange_unittest.cc

@@ -126,6 +126,19 @@ TEST(PRange, lambda_stop)
 	EXPECT_EQ(test, 3);
 }
 
+TEST(PRange, lambda_stop_shorter_method)
+{
+	int test = 6;
+	/* Stops before the 4th iteration */
+	for (auto i : progress(range(0, 6), [&]() { return test > 3; }))
+	{
+		(void)i;
+		std::this_thread::sleep_for(std::chrono::milliseconds(1000));
+		test--;
+	}
+	EXPECT_EQ(test, 3);
+}
+
 TEST(PRange, DISABLED_progress_incorrect_bounds_positive)
 {
 	range_io.enable_progress();