throws Throwable
  public static Value eregi_replace(Env env,                                    String patternString,                                    String replacement,                                    String subject)    throws Throwable  {    Pattern pattern = Pattern.compile(cleanRegexp(patternString, false),                                      Pattern.CASE_INSENSITIVE);    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);  }