Module: YABFI::Parser

Defined in:

lib/yabfi/parser.rb

Overview

This module contains a set of functions that lazily parse an IO object and yield a symbol for each non-comment character that is read in.

Constant Summary

DEFAULT_BUFFER_SIZE =

Maximum number of bytes to read in from the IO object at a time.

1_024

COMMAND_MAPPINGS =

Maps characters to human-readable Symbol command names.

{
  '+' => :succ,
  '-' => :pred,
  '>' => :next,
  '<' => :prev,
  ',' => :get,
  '.' => :put,
  '[' => :loop,
  ']' => :end
}

Class Method Summary

• .parse(io, buffer_size = DEFAULT_BUFFER_SIZE) {|command| ... } ⇒ Enumator<Symbol>

  Lazily parse an IO object while it still has input.

• .read(io, size) ⇒ String^?

  Block waiting for the next set of commands.

Class Method Details

.parse(io, buffer_size = DEFAULT_BUFFER_SIZE) {|command| ... } ⇒ Enumator<Symbol>

Lazily parse an IO object while it still has input.

Parameters:

• io (IO) —

  the object from which the parser lazily reads.

• buffer_size (Integer) (defaults to: DEFAULT_BUFFER_SIZE) —

  maximum size to request from the IO at once.

Yields:

• (command) —

  Symbol that represents the parsed command.

Returns:

• (Enumator<Symbol>) —

  of commands when no block is given.

# File 'lib/yabfi/parser.rb', line 28

def parse(io, buffer_size = DEFAULT_BUFFER_SIZE)
  return enum_for(:parse, io, buffer_size) unless block_given?
  loop do
    buffer = read(io, buffer_size)
    break unless buffer
    buffer.each_char do |char|
      command = COMMAND_MAPPINGS[char]
      yield command if command
    end
  end
end

.read(io, size) ⇒ String^?

Block waiting for the next set of commands.

Parameters:

• io (IO) —

  the object from which the parser lazily reads.

• size (Integer) —

  the maximum number of bytes to read in.

Returns:

• (String, nil) —

  the buffer of bytes read in, or nil on EOF.

# File 'lib/yabfi/parser.rb', line 45

def read(io, size)
  io.read_nonblock(size)
rescue IO::WaitReadable
  IO.select([io])
  retry
rescue EOFError
  nil
end