[WIP] Implemented split #66

src/iter.php

@@ -893,6 +893,36 @@ function join(string $separator, iterable $iterable): string {
     return $str;
 }
 
+/**
+ * Splits a string by a separator
+ *
+ * Examples:
+ *
+ *      iter\split(', ', 'a, b, c')
+ *      => iterable with values 'a', 'b' and 'c'
+ *
+ * @param string $separator Separator to use between elements
+ * @param string $data The iterable to join
+ *
+ * @return iterable
+ */
+function split(string $separator, string $data): iterable
+{
+    if (strlen($separator) === 0) {
+        throw new \InvalidArgumentException('Separator must be non-empty string');
+    }
+
+    $offset = 0;
+    while (
+        $offset < strlen($data)
+        && false !== $nextOffset = strpos($data, $separator, $offset)
+    ) {
+        yield substr($data, $offset, $nextOffset - $offset);
+        $offset = $nextOffset + strlen($separator);
+    }
+    yield substr($data, $offset);
+}
+
 /**
  * Returns the number of elements an iterable contains.
  *

test/iterTest.php

@@ -434,6 +434,18 @@ public function testJoin() {
         );
     }
 
+    public function testSplit() {
+        $this->assertSame(['a', 'b', 'c'], toArray(split(', ', 'a, b, c')));
+        $this->assertSame(['b', 'b', 'b', 'b', 'b', 'b', 'b'], toArray(split('a', 'babababababab')));
+
+        $this->assertSame(['a', 'b', '', '', 'c'], toArray(split(',', 'a,b,,,c')));
+        $this->assertSame(['', '', 'c'], toArray(split(',', ',,c')));
+        $this->assertSame(['c', '', ''], toArray(split(',', 'c,,')));
+
+        $this->expectException(\InvalidArgumentException::class);
+        toArray(split('', 'a'));
+    }
+
     public function testChunk() {
         $iterable = new \ArrayIterator(
             ['a' => 1, 'b' => 2, 'c' => 3, 'd' => 4, 'e' => 5]