Add clsas for MD_STD_STRINGS more obscure string operations

src/MD_STD_STRINGS.php

@@ -0,0 +1,39 @@
+<?PHP
+/**
+ * Gathers wrappers for handling strings.
+ */
+declare(strict_types = 1);
+
+/**
+ * Encapsulates functions for handling strings.
+ */
+final class MD_STD_STRINGS {
+    /**
+     * Duplicates words ending in a given set of strings (e.g. dots) that serve as bind chars
+     * to allow indexing to then allow searching for them in either form.
+     *
+     * @param string $input Input string.
+     *
+     * @return string
+     */
+    public static function duplicate_words_with_dots_for_indexing(string $input):string {
+
+        $charsToDuplicateOn = ',.!-';
+
+        $wordsToAdd = [];
+        $words = explode(' ', $input);
+        foreach ($words as $word) {
+            $trimmed = trim($word, $charsToDuplicateOn);
+            if ($trimmed !== $word) {
+                $wordsToAdd[] = $trimmed;
+            }
+        }
+
+        if (empty($wordsToAdd)) {
+            return $input;
+        }
+
+        return $input . ' ' . implode(' ', $wordsToAdd);
+
+    }
+}

src/testing/MD_STD_TEST_PROVIDERS.php

@@ -62,7 +62,7 @@ final class MD_STD_TEST_PROVIDERS {
     /**
      * Data provider for working mail addresses.
      *
-     * @return array<array{0: string, 1: string}>
+     * @return array<array{0: string}>
      */
     public static function invalid_email_provider():array {