/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.daffodil.dpath


object DPathUtil {

  /**
   * Whether a string is a DFDL expression (an XPath expression surrounded by brackets).
   *
   * This function does not verify a string conforms to the DFDL subset of XPath
   */
  def isExpression(expression: String): Boolean = {
    val trimmed = expression.trim
    trimmed.startsWith("{") && trimmed.endsWith("}") &&
      (trimmed(1) != '{')
  }
  /**
   * Returns the XPath expression contained in a DFDL expression (an XPath expression surrounded by brackets).
   *
   * @param expression a valid DFDL expression
   */
  def getExpression(expression: String): String = {
    val v = expression.trim
    v.substring(1, v.length - 1)
  }

}
