class Steep::AST::Location

def self.concat(*locations)
  locations.inject {|l1, l2|
    l1 + l2
  }
end

def +(other)
  if other
    raise "Invalid concat: buffer=#{buffer.name}, other.buffer=#{other.buffer.name}" unless other.buffer == buffer
    self.class.new(buffer: buffer,
                   start_pos: start_pos,
                   end_pos: other.end_pos)
  else
    self
  end
end

def ==(other)
  other.is_a?(Location) &&
    other.buffer == buffer &&
    other.start_pos == start_pos &&
    other.end_pos == end_pos
end

def end_column
  end_loc[1]
end

def end_line
  end_loc[0]
end

def end_loc
  @end_loc ||= buffer.pos_to_loc(end_pos)
end

def initialize(buffer:, start_pos:, end_pos:)
  @buffer = buffer
  @start_pos = start_pos
  @end_pos = end_pos
end

def inspect
  "#<#{self.class}:#{self.__id__} @buffer=#{buffer.name}, @start_pos=#{start_pos}, @end_pos=#{end_pos}, source='#{source.lines.first}', start_line=#{start_line}, start_column=#{start_column}>"
end

def name
  buffer.name
end

def pred?(loc)
  loc.is_a?(Location) &&
    loc.name == name &&
    loc.start_pos == end_pos
end

def source
  @source ||= buffer.source(start_pos...end_pos)
end

def start_column
  start_loc[1]
end

def start_line
  start_loc[0]
end

def start_loc
  @start_loc ||= buffer.pos_to_loc(start_pos)
end

def to_s
  "#{start_line}:#{start_column}...#{end_line}:#{end_column}"
end