dietrb

IMPORTANT! THIS REPO HAS BEEN MOVED TO http://svn.macosforge.org/repository/ruby/DietRB/trunk
AND IS AVAILABLE AS A GIT MIRROR ON http://github.com/MacRuby/DietRB.

= IRB on a diet, for MacRuby / Ruby 1.9

The goal is to have a small and cleaned up version of IRB. Trimmed down to only
do the stuff I, and most people I know, actually use.

Trimming down the core code is done mainly by using Ripper, which comes with
Ruby 1.9, instead of shipping it’s own parser etc.

There’s still lots to be done, but the ‘basic functionality’ as is now, should
not grow too much more. For now my things to-do are .irbrc support, completion,
and investigate what else people really really need. After that it’s time to
polish.

= Important notice

Since on Ruby 1.9 all latest gems are pushed onto the load path by default,
installing the DietRB gem would break the existing IRB binary. Therefor, with
the DietRB gem is installed, it will hijack the `irb’ bin file.

The original IRB will still work when you uninstall the DietRB gem, though.

== Extensions

• irb/ext/colorize.rb, adds support for colorizing the prompt and result. The
  code was based upon Wirble’s implementation, so your custom Wirble themes
  should still work.

  Configure it with:

  • IRB.formatter.color_scheme = scheme, where scheme can be: :dark_background,
    :light_background, or :fresh. Defaults to :dark_background.

  • IRB.formatter.colors returns the hash of current token-type to color
    mappings.

• irb/ext/completion.rb, adds, as the name implies, autocompletion for
  constants, variables, methods, etc.

• irb/ext/history.rb, stores/loads the history in and from the history file,
  which is located at ~/.irb_history.

  It provides the following API:

  • Kernel#history(N), or Kernel#h, will show N number of the most recent history
    entries. Defaults to 50.

  • Kernel#history!(entry_or_range), or Kernel#h!, will execute the specified
    history entry, or entries if a range is given.

  • Kernel#clear_history! will clear the history and the history file.

== Differences

• Dietrb will try to warn about syntax errors as soon as a line is entered and
  only reset the buffer to the previous line. This means that you don’t need to
  loose any previous work:

  IRB:

  irb(main):001:0> class A
  irb(main):002:1> def foo
  irb(main):003:2> } p :ok
  irb(main):004:1> end
  SyntaxError: compile error
  (irb):3: syntax error, unexpected ‘}’
  } p :ok
  ^
  (irb):4: syntax error, unexpected $end, expecting kEND
  from (irb):4
  from :0
  irb(main):005:0> A.new.foo
  NameError: uninitialized constant A
  from (irb):5
  from :0

  Dietrb:

  irb(main):001:0> class A
  irb(main):002:1> def foo
  irb(main):003:2> } p :ok
  SyntaxError: compile error
  (irb):3: syntax error, unexpected ‘}’
  irb(main):004:2> p :ok
  irb(main):005:2> end
  irb(main):006:1> end
  => nil
  irb(main):007:0> A.new.foo
  :ok
  => :ok

== Play

Normal usage:

irb(main):001:0> class A
irb(main):002:1> def foo
irb(main):003:2> :ok
irb(main):004:2> end
irb(main):005:1> end
=> nil
irb(main):006:0> irb A.new
irb(#<#Class:…::A:…>):001:0> foo
=> :ok
irb(#<#Class:…::A:…>):002:0> quit
=> nil
irb(main):007:0> quit