2026-01-18-13-01-23 DB: Updated code for chapter 3

Author: dbierer

src/Chapter03/ch03_dev_func_type_hints_lib_runner.php

@@ -0,0 +1,41 @@
+<?php
+namespace Library;
+use DateTime;
+include (__DIR__ . DIRECTORY_SEPARATOR . 'ch03_developing_func_type_hints_library.php');
+
+/*
+
+try {
+    $callable = function () { return 'Callback Return'; };
+    echo someTypeHint([1,2,3], new DateTime(), $callable);
+    echo someTypeHint('A', 'B', 'C');
+} catch (TypeError $e) {
+    echo $e->getMessage();
+    echo PHP_EOL;
+}
+
+try {
+    echo someScalarHint(TRUE, 11, 22.22, 
+        'This is a string');
+    echo someScalarHint('A', 'B', 'C', 'D');
+} catch (TypeError $e) {
+    echo $e->getMessage();
+}
+*/
+
+try {
+    // positive results
+    $b = someBooleanHint(TRUE);
+    $i = someBooleanHint(11);
+    $f = someBooleanHint(22.22);
+    $s = someBooleanHint('X');
+    var_dump($b, $i, $f, $s);
+    // negative results
+    $b = someBooleanHint(FALSE);
+    $i = someBooleanHint(0);
+    $f = someBooleanHint(0.0);
+    $s = someBooleanHint('');
+    var_dump($b, $i, $f, $s);
+} catch (TypeError $e) {
+    echo $e->getMessage();
+}

src/Chapter03/ch03_developing_func_type_hints_library.php

@@ -0,0 +1,29 @@
+<?php
+declare(strict_types=1);
+namespace Library;
+use DateTime;
+
+function someTypeHint(array $a, DateTime $t, callable $c)
+{
+  $message = '';
+  $message .= 'Array Count: ' . count($a) . PHP_EOL;
+  $message .= 'Date: ' . $t->format('Y-m-d') . PHP_EOL;
+  $message .= 'Callable Return: ' . $c() . PHP_EOL;
+  return $message;
+}
+
+function someScalarHint(bool $b, int $i, float $f, string $s)
+{
+  return sprintf("\n%20s : %5s\n%20s : %5d\n%20s " . 
+                 ": %5.2f\n%20s : %20s\n\n",
+                 'Boolean', ($b ? 'TRUE' : 'FALSE'),
+                 'Integer', $i,
+                 'Float',   $f,
+                 'String',  $s);
+}
+
+function someBoolHint(bool $b)
+{
+  return $b;
+}
+

src/Chapter03/ch03_gen_ai_prompts_address_form.php

@@ -394,7 +394,7 @@ function generateNameAddressForm($fieldAttrs, $countries, $formAction = '', $for
         $html .= '<div class="form-group">' . PHP_EOL;
         $html .= '<label for="' . $fieldName . '"';
         $html .= ($isRequired) ? ' class="required"' : '';
-        $html .= '>' . $fieldLabel);
+        $html .= '>' . $fieldLabel;
         $html .= (!$isRequired) ? ' <span class="optional">(Optional)</span>' : '';
         $html .= '</label>' . PHP_EOL;        
         // Generate input field based on type

src/Chapter03/ch03_gen_ai_prompts_type_hint.php

@@ -0,0 +1,29 @@
+<?php
+/*
+// 1st pass:
+function applyPercentage(array $numbers, float $percentage): array
+{
+    return array_map(fn($n) => $n * ($percentage / 100), $numbers);
+}
+$arr = new ArrayObject(range(1,10));
+var_dump(applyPercentage($arr, 8));
+// result: Fatal Error
+*/
+
+// 2nd pass:
+/**
+ * Applies a percentage factor to each element in an iterable of numeric values.
+ *
+ * @param iterable $arr The iterable containing numeric values.
+ * @param int $percent The percentage factor to apply (e.g., 10 for 10%, 150 for 150%).
+ * @return iterable The modified iterable with the percentage factor applied.
+ */
+function applyPercentage(iterable $arr, int $percent): iterable
+{
+    foreach ($arr as $key => $value) {
+        yield $key => $value * ($percent / 100);
+    }
+}
+
+$arr = new ArrayObject(range(1,10));
+var_dump(iterator_to_array(applyPercentage($arr, 8)));