class RuboCop::Cop::Style::Semicolon

foo = 1; bar = 2
# good
@example AllowAsExpressionSeparator: true
foo = 1; bar = 2
# bad
@example AllowAsExpressionSeparator: false (default)
baz = 3
bar = 2
foo = 1
# good
baz = 3;
foo = 1; bar = 2;
# bad
@example
It allows ‘;` to separate several expressions on the same line.
This cop has `AllowAsExpressionSeparator` configuration option.
It also checks for lines terminated with a semicolon.
This cop checks for multiple expressions placed on the same line.

def self.autocorrect_incompatible_with 

def self.autocorrect_incompatible_with
  [Style::SingleLineMethods]
end

def check_for_line_terminator_or_opener 

def check_for_line_terminator_or_opener
  # Make the obvious check first
  return unless processed_source.raw_source.include?(';')
  each_semicolon { |line, column| register_semicolon(line, column, false) }
end

def each_semicolon 

def each_semicolon
  tokens_for_lines.each do |line, tokens|
    yield line, tokens.last.column if tokens.last.semicolon?
    yield line, tokens.first.column if tokens.first.semicolon?
  end
end

def expressions_per_line(exprs) 

def expressions_per_line(exprs)
  # create a map matching lines to the number of expressions on them
  exprs_lines = exprs.map(&:first_line)
  exprs_lines.group_by(&:itself)
end

def find_semicolon_positions(line) 

def find_semicolon_positions(line)
  # Scan for all the semicolons on the line
  semicolons = processed_source[line - 1].enum_for(:scan, ';')
  semicolons.each do
    yield Regexp.last_match.begin(0)
  end
end

def on_begin(node) 

def on_begin(node)
  return if cop_config['AllowAsExpressionSeparator']
  exprs = node.children
  return if exprs.size < 2
  expressions_per_line(exprs).each do |line, expr_on_line|
    # Every line with more than one expression on it is a
    # potential offense
    next unless expr_on_line.size > 1
    find_semicolon_positions(line) { |pos| register_semicolon(line, pos, true) }
  end
end

def on_new_investigation 

def on_new_investigation
  return if processed_source.blank?
  check_for_line_terminator_or_opener
end

def register_semicolon(line, column, after_expression) 

def register_semicolon(line, column, after_expression)
  range = source_range(processed_source.buffer, line, column)
  add_offense(range) do |corrector|
    if after_expression
      corrector.replace(range, "\n")
    else
      corrector.remove(range)
    end
  end
end

def tokens_for_lines 

def tokens_for_lines
  processed_source.tokens.group_by(&:line)
end