crafting-interpreters/ruby/bin/lox

#!/usr/bin/env ruby -w

$LOAD_PATH.unshift(File.expand_path("../lib", __dir__))

require "lox"

def run_prompt
  loop do
    print "> "
    line = gets
    break if line.nil? || line.empty?
    begin
      run(line)
    rescue Lox::ParseError => e
      STDERR.puts e.message
    rescue Lox::RuntimeError => e
      STDERR.puts e.message
    end
  end
end

def run_file(io)
  run(io.read)
rescue Lox::ParseError => e
  STDERR.puts e.message
  exit 65
rescue Lox::RuntimeError => e
  STDERR.puts e.message, "[line #{e.token.line}]"
  exit 70
end

def run(src)
  Lox::Runner.new.run(src)
end


if __FILE__ == $0
  puts "Usage: #$0 [script]" or exit 64 if ARGV.length > 1

  if ARGV.empty?
    run_prompt
  else
    run_file(ARGF)
  end
end