JingwenTian · September 26, 2018 20:22 · Mar 9, 2017
diff --git a/exceptions-tree.php b/exceptions-tree.php
@@ -0,0 +1,70 @@
+<?php
+
+if (!function_exists('interface_exists')) {
+    die('PHP version too old');
+}
+$throwables = listThrowableClasses();
+$throwablesPerParent = splitInParents($throwables);
+printTree($throwablesPerParent);
+if (count($throwablesPerParent) !== 0) {
+    die('ERROR!!!');
+}
+
+function listThrowableClasses()
+{
+    $result = [];
+    if (interface_exists('Throwable')) {
+        foreach (get_declared_classes() as $cn) {
+            $implements = class_implements($cn);
+            if (isset($implements['Throwable'])) {
+                $result[] = $cn;
+            }
+        }
+    } else {
+        foreach (get_declared_classes() as $cn) {
+            if ($cn === 'Exception' || is_subclass_of($cn, 'Exception')) {
+                $result[] = $cn;
+            }
+        }
+    }
+
+    return $result;
+}
+
+function splitInParents($classes)
+{
+    $result = [];
+    foreach ($classes as $cn) {
+        $parent = (string) get_parent_class($cn);
+        if (isset($result[$parent])) {
+            $result[$parent][] = $cn;
+        } else {
+            $result[$parent] = [$cn];
+        }
+    }
+
+    return $result;
+}
+
+function printTree(&$tree)
+{
+    if (!isset($tree[''])) {
+        die('No root classes!!!');
+    }
+    printLeaves($tree, '', 0);
+}
+function printLeaves(&$tree, $parent, $level)
+{
+    if (isset($tree[$parent])) {
+        $leaves = $tree[$parent];
+        unset($tree[$parent]);
+        natcasesort($leaves);
+        $leaves = array_values($leaves);
+        $count = count($leaves);
+        for ($i = 0; $i < $count; ++$i) {
+            $leaf = $leaves[$i];
+            echo str_repeat('   ', $level), $leaf, "\n";
+            printLeaves($tree, $leaf, $level + 1);
+        }
+    }
+}