Class: Campa::Repl

Inherits:
Object
  • Object
show all
Defined in:
lib/campa/repl.rb

Instance Method Summary collapse

Constructor Details

#initialize(evaler, context, reader: Reader) ⇒ Repl

It creates a new Context that uses one given as a parameter to this contructor to evaluate expressions typed in the REPL.

Parameters:

  • evaler (Evaler) —

    used to extract value from expressions

  • context (Context) —

    against which expressions will be evaled

  • reader (Reader) (defaults to: Reader) —

    to return expressions to be evaled



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# File 'lib/campa/repl.rb', line 10

def initialize(evaler, context, reader: Reader)
  @reader = reader
  @evaler = evaler
  @context = context
  @environment = @context.push(Context.new)
  @printer = Printer.new
end

Instance Method Details

#run(input, output) ⇒ Object

Uses the #getc method from the parameter input to create a (probably blocking) loop to evaluate code “live” creating a REPL session.

Captures the Interrupt exception to break the loop and finish the current REPL session.

rubocop: disable Metrics/MethodLength

Parameters:

  • input (IO) —

    an IO like object from where tokens will be extracted

  • output (IO) —

    IO like object to receive the output from evaluating the forms



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# File 'lib/campa/repl.rb', line 30

def run(input, output)
  output.print "=> "
  reader = @reader.new(input)

  loop do
    begin
      token = reader.next
      break if token.nil?

      show(output, evaler.call(token, environment))
    rescue ExecutionError => e
      handle_exec_error(output, e)
    rescue StandardError => e
      handle_standard_error(output, e)
    end

    output.print "=> "
  end
rescue Interrupt
  output.puts "see you soon"
end