conditional operator associativity experiment

experiments/ConditionalOperatorAssociativity.php

@@ -0,0 +1,36 @@
+<?php
+
+/*
+ * PURPOSE:
+ * Understand the associativity properties of the conditional operator.
+ * This experiment compares the result of a nested ternary to the expected
+ * left and right associative results.
+ *
+ * RESULTS:
+ * input  : 1
+ * output : three
+ * => Left-associative :(
+ *
+ * CONCLUSION:
+ * Conditional operators are left associative :(
+ */
+
+$i = 1;
+
+$label =
+    $i === 1 ? "one" :
+    $i === 2 ? "two" :
+    $i === 3 ? "three" :
+    "error";
+
+echo "input  : ", $i, PHP_EOL;
+echo "output : ", $label, PHP_EOL;
+echo "=> ";
+if ($label === "one") {
+    echo "Right-associative :)";
+} else {
+    echo "Left-associative :(";
+}
+
+$a = 1=== 2? false : $d = 3;
+echo $d;