coalesce.php

php/coalesce.php

@@ -0,0 +1,50 @@
+<?php
+
+/**
+ * Simple php equivalent of Oracle's coalesce()
+ *
+ * It can be used as simple oneline-alternative to switch or if operators in many
+ * cases without difficult logic. For example, get first non-empty value from bunch of vars:
+ *
+ * echo coalesce($var1, $var2, $var3, ...);
+ *
+ * is alternative to:
+ *
+ * if ($var1) {
+ *     return $var1;
+ * } elseif ($var2) {
+ *     return $var2;
+ * } elseif ....
+ *
+ * or
+ *
+ * return $var1 ?? $var2 ?? $var3 ...
+ *
+ * @see https://docs.oracle.com/cd/B28359_01/server.111/b28286/functions023.htm
+ * @see https://gist.github.com/anthonyaxenov/f30961849d5bfb2651901af120607694
+ * @author Anthony Axenov
+ * @return mixed|null
+ */
+function coalesce() {
+    foreach (func_get_args() as $arg) {
+        if (is_callable($arg)) {
+            $arg = call_user_func($arg);
+        }
+        if ($arg !== null) {
+            return $arg;
+        }
+    }
+    return null;
+}
+
+//usage:
+
+$var1 = null;
+$var2 = function() use ($var1) {
+    return $var1;
+};
+$var3 = 3;
+$var4 = '4';
+
+$result = coalesce($var1, $var2, $var3, $var4);
+var_dump($result);