Regex to match everything before a word. To be used in nant script

Question

I was writing some build scripts for my project. I wanted a regex pattern which can match everything before a particular word. For eg: My script looks like this

Create Table ABC(
id int(50)
)

--//@UNDO

Drop table ABC

I want to match everything before --//@UNDO using nant regex task. How do I implement it??

I also want it to match everything in the file if --//@UNDO is not present in the file. I am not getting a way around

Answer 1

This is what I ended up doing

<loadfile file="${filePathAndName}" property="file.contents" />
    <property name="fileHasUndo" value="${string::index-of(file.contents, '--//@UNDO')}" />
    <choose>
      <when test="${fileHasUndo ==  '-1' }">
          <echo file="${file}" append="true" message="${file.contents}" />
      </when>
      <otherwise>
        <regex pattern="(?'sql'[\s\S]*)--\/\/@UNDO[\s\S]*"  input="${file.contents}" options="Multiline"/>
        <echo file="${file}" append="true" message="${sql}" />
      </otherwise>
    </choose>

I found the index of --//@UNDO. And depending on its presence I am doing a choose when.. Solved the problem