repl.rb

require 'readline'
require 'parser/current'
# TODO: detect version of Ruby being used, and require the appropriate parser
# require 'parser/rubyXY'

# opt into newer AST format since we're not maintaining backward compatibility with old formats!
Parser::Builders::Default.emit_lambda   = true
Parser::Builders::Default.emit_procarg0 = true
Parser::Builders::Default.emit_encoding = true
Parser::Builders::Default.emit_index    = true

### Our Unicode Characters
THE_END     = "\u0004"
LINE_BREAK  = "\u0085"


### Let's exit gracefully ###
def goodbye(newline: true)
  puts if newline
  puts "Exiting Optic Ruby Parser."
end
Signal.trap("INT")  { goodbye; exit }
Signal.trap("TERM") { goodbye; exit }

# for testing:
#puts "Your process ID is #{Process.pid}"

# READ
while input = Readline.readline(">: ", true)
  break if input == nil # handle ⌃D
  input.chomp!
  break if ["exit", "quit", ":q"].include? input

  # EVAL (actually: parse into AST)
  ast = Parser::CurrentRuby.parse(input)

  # PRINT
  puts ast.to_s.gsub(/\s+/,' ') + THE_END
end
# LOOP

goodbye(newline: false)