class Grammar::ParserError

When the parser fails on a line from user input

Constants

LINES_AFTER
LINES_BEFORE

Public Class Methods

new(line_number, reason, source) click to toggle source
# File lib/emerald/grammar.rb, line 26
def initialize(line_number, reason, source)
  @line_number = line_number
  @reason = reason
  @source = source
end

Public Instance Methods

message() click to toggle source
# File lib/emerald/grammar.rb, line 32
def message
  messages = []
  if match = @reason.match(/(Expected .+?) at line/)
    messages << match[1]
  else
    messages << @reason
  end

  lines = @source.split(/\n/)
  LINES_BEFORE.downto(1).each do |i|
    messages << '    ' + lines[@line_number - i - 1] if lines[@line_number - i - 1]
  end
  messages << '>>> ' + lines[@line_number - 1]
  1.upto(LINES_AFTER).each do |i|
    messages << '    ' + lines[@line_number + i - 1] if lines[@line_number + i - 1]
  end

  messages.join("\n")
end