add word tokenizer

src/Phpml/Tokenization/WordTokenizer.php

@@ -0,0 +1,21 @@
+<?php
+
+declare (strict_types = 1);
+
+namespace Phpml\Tokenization;
+
+class WordTokenizer implements Tokenizer
+{
+    /**
+     * @param string $text
+     *
+     * @return array
+     */
+    public function tokenize(string $text): array
+    {
+        $tokens = [];
+        preg_match_all('/\w\w+/u', $text, $tokens);
+
+        return $tokens[0];
+    }
+}

tests/Phpml/Tokenization/WordTokenizerTest.php

@@ -0,0 +1,40 @@
+<?php
+
+declare (strict_types = 1);
+
+namespace tests\Tokenization;
+
+use Phpml\Tokenization\WordTokenizer;
+
+class WordTokenizerTest extends \PHPUnit_Framework_TestCase
+{
+    public function testTokenizationOnAscii()
+    {
+        $tokenizer = new WordTokenizer();
+
+        $text = 'Lorem ipsum-dolor sit amet, consectetur/adipiscing elit.
+                 Cras consectetur, dui et lobortis;auctor. 
+                 Nulla vitae ,.,/ congue lorem.';
+
+        $tokens = ['Lorem', 'ipsum', 'dolor', 'sit', 'amet', 'consectetur', 'adipiscing', 'elit',
+                 'Cras', 'consectetur', 'dui', 'et', 'lobortis', 'auctor',
+                 'Nulla', 'vitae', 'congue', 'lorem', ];
+
+        $this->assertEquals($tokens, $tokenizer->tokenize($text));
+    }
+
+    public function testTokenizationOnUtf8()
+    {
+        $tokenizer = new WordTokenizer();
+
+        $text = '鋍鞎 鳼 鞮鞢騉 袟袘觕, 炟砏 蒮 謺貙蹖 偢偣唲 蒛 箷箯緷 鑴鱱爧 覮轀,
+                 剆坲 煘煓瑐 鬐鶤鶐 飹勫嫢 銪 餀 枲柊氠 鍎鞚韕 焲犈,
+                 殍涾烰 齞齝囃 蹅輶 鄜, 孻憵 擙樲橚 藒襓謥 岯岪弨 蒮 廞徲 孻憵懥 趡趛踠 槏';
+
+        $tokens = ['鋍鞎', '鞮鞢騉', '袟袘觕', '炟砏', '謺貙蹖', '偢偣唲', '箷箯緷', '鑴鱱爧', '覮轀',
+                  '剆坲', '煘煓瑐', '鬐鶤鶐', '飹勫嫢', '枲柊氠', '鍎鞚韕', '焲犈',
+                  '殍涾烰', '齞齝囃', '蹅輶', '孻憵', '擙樲橚', '藒襓謥', '岯岪弨', '廞徲', '孻憵懥', '趡趛踠', ];
+
+        $this->assertEquals($tokens, $tokenizer->tokenize($text));
+    }
+}