Fix steps with asterisk value

README.md

@@ -45,6 +45,7 @@ use Orisai\CronExpressionExplainer\DefaultCronExpressionExplainer;
 $explainer = new DefaultCronExpressionExplainer();
 
 $explainer->explain('* * * * *'); // At every minute.
+$explainer->explain('*/30 * * * *'); // At every 30th minute.
 $explainer->explain('@daily'); // At 00:00.
 $explainer->explain('* * 1 * 1'); // At every minute on day-of-month 1 and on every Monday.
 $explainer->explain('0 22 * 12 *'); // At 22:00 in December.

docs/README.md

@@ -26,6 +26,7 @@ use Orisai\CronExpressionExplainer\DefaultCronExpressionExplainer;
 $explainer = new DefaultCronExpressionExplainer();
 
 $explainer->explain('* * * * *'); // At every minute.
+$explainer->explain('*/30 * * * *'); // At every 30th minute.
 $explainer->explain('@daily'); // At 00:00.
 $explainer->explain('* * 1 * 1'); // At every minute on day-of-month 1 and on every Monday.
 $explainer->explain('0 22 * 12 *'); // At 22:00 in December.

src/Interpreter/BasePartInterpreter.php

@@ -39,18 +39,26 @@ public function explainPart(Part $part, bool $renderName = true): string
 		}
 
 		if ($part instanceof StepPart) {
+			$range = $part->getRange();
 			$step = $part->getStep();
 
 			// Range with step === 1 is the same as range without step
 			if ($step === 1) {
-				return $this->explainPart($part->getRange());
+				return $this->explainPart($range);
+			}
+
+			if ($range instanceof ValuePart && $range->getValue() === '*') {
+				return 'every '
+					. $step
+					. $this->getNumberExtension($step)
+					. " {$this->getInStepName()}";
 			}
 
 			return 'every '
 				. $step
 				. $this->getNumberExtension($step)
 				. " {$this->getInStepName()} "
-				. $this->explainPart($part->getRange(), false);
+				. $this->explainPart($range, false);
 		}
 
 		if ($part instanceof RangePart) {

src/Part/PartParser.php

@@ -31,13 +31,15 @@ private function parseUnlistedPart(string $part, BasePartInterpreter $interprete
 	{
 		if (str_contains($part, '/')) {
 			$stepParts = explode('/', $part, 2);
+
 			$step = (int) $stepParts[1];
 			assert((string) $step === $stepParts[1]);
 
-			return new StepPart(
-				$this->parseRangePart($stepParts[0], $interpreter),
-				$step,
-			);
+			$range = str_contains($stepParts[0], '-')
+				? $this->parseRangePart($stepParts[0], $interpreter)
+				: $this->parseValuePart($stepParts[0], $interpreter);
+
+			return new StepPart($range, $step);
 		}
 
 		if (str_contains($part, '-')) {

src/Part/StepPart.php

@@ -5,17 +5,24 @@
 final class StepPart implements Part
 {
 
-	private RangePart $range;
+	/** @var RangePart|ValuePart */
+	private Part $range;
 
 	private int $step;
 
-	public function __construct(RangePart $range, int $step)
+	/**
+	 * @param RangePart|ValuePart $range
+	 */
+	public function __construct(Part $range, int $step)
 	{
 		$this->range = $range;
 		$this->step = $step;
 	}
 
-	public function getRange(): RangePart
+	/**
+	 * @return RangePart|ValuePart
+	 */
+	public function getRange(): Part
 	{
 		return $this->range;
 	}

tests/Unit/DefaultCronExpressionExplainerTest.php

@@ -76,6 +76,11 @@ public function provideExplain(): Generator
 			'At every minute from 1 through 15 and from 31 through 45.',
 		];
 
+		yield [
+			'*/30 * * * *',
+			'At every 30th minute.',
+		];
+
 		yield [
 			'1-30/1 * * * *',
 			'At every minute from 1 through 30.',
@@ -173,6 +178,11 @@ public function provideExplain(): Generator
 			'At every minute past every hour from 1 through 5 and from 11 through 15.',
 		];
 
+		yield [
+			'* */2 * * *',
+			'At every minute past every 2nd hour.',
+		];
+
 		yield [
 			'* 1-10/1 * * *',
 			'At every minute past every hour from 1 through 10.',
@@ -297,6 +307,11 @@ public function provideExplain(): Generator
 			'At every minute on every day-of-month from 1 through 5 and from 11 through 15.',
 		];
 
+		yield [
+			'* * */2 * *',
+			'At every minute on every 2nd day-of-month.',
+		];
+
 		yield [
 			'* * 1-10/1 * *',
 			'At every minute on every day-of-month from 1 through 10.',
@@ -469,6 +484,11 @@ public function provideExplain(): Generator
 			'At every minute on every day-of-week from Sunday through Tuesday and from Thursday through Saturday.',
 		];
 
+		yield [
+			'* * * * */2',
+			'At every minute on every 2nd day-of-week.',
+		];
+
 		yield [
 			'* * * * 2-4/1',
 			'At every minute on every day-of-week from Tuesday through Thursday.',
@@ -671,6 +691,11 @@ public function provideExplain(): Generator
 			'At every minute in every month from January through March and from May through July.',
 		];
 
+		yield [
+			'* * * */2 *',
+			'At every minute in every 2nd month.',
+		];
+
 		yield [
 			'* * * 2-4/1 *',
 			'At every minute in every month from February through April.',