throws Throwable
  public static Value ereg_replace(Env env,                                   String patternString,                                   String replacement,                                   String subject)    throws Throwable  {    Pattern pattern = Pattern.compile(cleanRegexp(patternString, false));    ArrayList<Replacement> replacementProgram      = _replacementCache.get(replacement);    if (replacementProgram == null) {      replacementProgram = compileReplacement(env, replacement, false);      _replacementCache.put(replacement, replacementProgram);    }    return pregReplaceStringImpl(env,				 pattern,				 replacementProgram,				 subject,				 -1,				 NullValue.NULL,				 false);  }