argumentRange method

SourceRange argumentRange(ArgumentList argumentList, int lower, int upper, bool forDeletion,)

Return a source range that covers all of the arguments in the argumentList between the lower and upper indices, inclusive. The flag forDeletion controls whether a comma between the given indices and the neighboring arguments should be included in the range. If the flag is true, then the range can be deleted to delete the covered arguments and leave a valid argument list. If the flag is false, then the range can be replaced with different argument values.

For example, given an argument list of (a, b, c, d), a lower index of 1 and an upper index of 2, the range will cover the text 'b, c' if forDeletion is false and the text ', b, c' if forDeletion is true.

Throws and exception if either the lower or upper bound is not a valid index into the argumentList or if the upper bound is less than the lower bound.

Implementation

SourceRange argumentRange(
    ArgumentList argumentList, int lower, int upper, bool forDeletion) {
  var arguments = argumentList.arguments;
  assert(lower >= 0 && lower < arguments.length);
  assert(upper >= lower && upper < arguments.length);
  if (lower == upper) {
    // Remove a single argument.
    if (forDeletion) {
      return nodeInList(arguments, arguments[lower]);
    }
    return node(arguments[lower]);
  } else if (!forDeletion) {
    return startEnd(arguments[lower], arguments[upper]);
  } else if (lower == 0) {
    if (upper == arguments.length - 1) {
      // Remove all of the arguments.
      return endStart(
          argumentList.leftParenthesis, argumentList.rightParenthesis);
    } else {
      // Remove a subset of the arguments starting with the first argument.
      return startStart(arguments[lower], arguments[upper + 1]);
    }
  } else {
    // Remove a subset of the arguments starting in the middle of the
    // arguments.
    return endEnd(arguments[lower - 1], arguments[upper]);
  }
}