title: preg_match error: Compilation failed: missing terminating ] for character class
body: <p>I've got a series of .txt files that I'm reading in a for loop. And I've placed a token in some of the text files in the form [widget_]</p>
  
  <p>So, the entire contents of the text file might be [widget_search] for example. And another text file might contain the content [widget_recent-posts]. Others might just have html formatted text and not have the token at all.</p>
  
  <p>In the for loop, I'm doing a preg_match to see if the text file is one in which the contents matches my token pattern. And if a match, I'm executing some conditional code.</p>
  
  <p>However, I'm getting an error when I run a trace test to see if there's a match.</p>
  
  <p>The error is:</p>
  
  <p>Warning: preg_match() [function.preg-match]: Compilation failed: missing terminating ] for character class at offset 8 in C:\xampplite\htdocs\test\wp-content\plugins\widget-test\widget-test.php on line 227</p>
  
  <p>And here's the code at line 227:</p>
  
  <pre><code>if (preg_match("/[widget_/i",$widget_text)) {//do something}
  </code></pre>