Provided by: jruby_9.1.13.0-1_all bug


       jirb1.3 - interactive JRuby


       jirb [options]


       irb  stands  for  `interactive  JRuby'.  irb  is  a  tool  to  execute interactively JRuby
       expressions read from stdin.  Use of jirb is easy if  you  know  JRuby.   Executing  jirb,
       prompts are displayed as follows. Then, enter expression of ruby. A input is executed when
       it is syntacticaly completed.

           $ jirb1.3
           irb(main):001:0> 1+2
           irb(main):002:0> class Foo
           irb(main):003:1>  def foo
           irb(main):004:2>    print 1
           irb(main):005:2>  end
           irb(main):006:1> end

       And, Readline extesion module can be used with irb. Using Readline is the standard default
       action if Readline is installed.


       -f     suppress read ~/.irbrc

       -m     bc mode (fraction or matrix are available)

       -d     set $DEBUG  to true (same as `ruby -d')

       -r load-module
              same as `ruby -r'

              uses `inspect' for output (the default except bc mode)

              doesn't uses inspect for output

              uses Readline extension module

              doesn't use Readline extension module

       --prompt prompt-mode

       --prompt-mode prompt-mode
              switches  prompt  mode. Pre-defined prompt modes are `default', `simple', `xmp' and

              uses prompt appreciate for inf-ruby-mode on emacs.  Suppresses --readline.

              simple prompt mode

              no prompt

              display trace for each execution of commands.

       --back-trace-limit n
              displayes backtrace top n and tail n. The default value is 16.

       --irb_debug n
              sets internal debug level to n (It shouldn't be used)

       -v, --version
              prints the version of irb


       jirb reads `~/.irbrc' when it is invoked. If `~/.irbrb' doesn't exist jirb try to read  in
       the  order `.irbrc', `irb.rc', `_irbrc' then `$irbrc'.  The following is altanative to the
       command line option. To use them type as follows in a jirb session.

           IRB.conf[:IRB_RC] = nil
           IRB.conf[:USE_LOADER] = false
           IRB.conf[:USE_READLINE] = nil
           IRB.conf[:USE_TRACER] = false
           IRB.conf[:IGNORE_SIGINT] = true
           IRB.conf[:IGNORE_EOF] = false
           IRB.conf[:PROMPT_MODE] = :DEFALUT
           IRB.conf[:PROMPT] = {...}

Customizing prompt

       To costomize the prompt you set a variable


       For example, describe as follows in `.irbrc'.

           IRB.conf[:PROMPT][:MY_PROMPT] = { # name of prompt mode
             :PROMPT_I => nil,         # normal prompt
             :PROMPT_S => nil,         # prompt for continuated strings
             :PROMPT_C => nil,         # prompt for continuated statement
             :RETURN => "    ==>%s\n"       # format to return value

       Then, invoke irb with the above prompt mode by

           $ jirb1.3 --prompt my-prompt

       Or add the following in `.irbrc'.

           IRB.conf[:PROMPT_MODE] = :MY_PROMPT

       Constants  PROMPT_I,  PROMPT_S  and  PROMPT_C  specifies  the  format.   In   the   prompt
       specification, some special strings are available.

           %N    command name which is running
           %m    to_s of main object (self)
           %M    inspect of main object (self)
           %l    type of string(", ', /, ]), `]' is inner %w[...]
           %NNi  indent level. NN is degits and means as same as printf("%NNd").
                 It can be ommited
           %NNn  line number.
           %%    %
       For     instance,     the     default    prompt    mode    is    defined    as    follows:
       IRB.conf[:PROMPT_MODE][:DEFAULT] = {

       PROMPT_I => "%N(%m):%03n:%i> ",

       PROMPT_S => "%N(%m):%03n:%i%l ",

       PROMPT_C => "%N(%m):%03n:%i* ",

       RETURN => "%s\n"}
              RETURN is used to printf.

Configurating subirb

       The command line option or IRB.conf specify the default behavior of (sub)irb. On the other
       hand,  each  conf  of  in the next sction `6. Command' is used to individually configurate
       (sub)irb.  If proc is set to IRB.conf[:IRB_RC], its subirb will be invoked after execution
       of  that  proc  under  giving  the context of irb as its aregument. By this mechanism each
       subirb can be configurated.


       For irb commands, both simple name and `irb_'-prefixed name are prepared.

       exit, quit, irb_exit
              Quits (sub)irb.  if you've done cb (see below), exit from the binding mode.

       conf, irb_context
              Displays current configuration. Modifing the configuration is achieved  by  sending
              message to `conf'.

              Sets display lines of backtrace as top n and tail n.  The default value is 16.

       conf.debug_level = N
              Sets debug level of irb.

       conf.ignore_eof = true/false
              Whether ^D (control-d) will be ignored or not.  If false is set, ^D means quit.

       conf.ignore_sigint= true/false
              Whether ^C (control-c) will be ignored or not.  If false is set, ^D means quit.  If
                  during input:   cancel inputing then return to top level.
                  during execute: abondon current execution.

       conf.inf_ruby_mode = true/false
              Whether inf-ruby-mode or not. The default value is false.

       conf.inspect_mode = true/false/nil
              Specifies inspect mode.  true:  display inspect false: display to_s nil:    inspect
              mode in non math mode,
                  non inspect mode in math mode.

              The level of cb.

              Whether bc mode or not.

       conf.use_loader = true/false
              Whether  irb's  own file reader method is used when load/require or not.  This mode
              is globaly affected (irb wide).

              prompt for a continuating statement (e.g, immediately after of `if')

              standard prompt

              prompt for a continuating string

              Whether ~/.irbrc is read or not.

       conf.use_prompt = true/false
              Prompting or not.

       conf.use_readline = true/false/nil
              Whether readline is used or not.  true: uses false: doen't use nil: intends to  use
              readline except for inf-reuby-mode (default)

              Whether verbose messages are display or not.

       cb, irb_change_binding [obj]
              Enter  new binding which has a distinct scope of local variables.  If obj is given,
              obj will be self.

       irb [obj]
              Invoke subirb. If obj is given, obj will be self.

       jobs, irb_jobs
              List of subirb

       fg n, irb_fg n
              Switch into specified subirb. The following is candidates of n:
                  irb number
                  irb object
                  self(obj which is specified of irb obj)

       kill n, irb_kill n
              Kill subirb. The means of n is as same as the case of irb_fg.

System variable

       _      The latest value of evaluation (it is local)

Session Example

           $ jirb1.3
           irb(main):001:0> irb                        # invoke subirb
           irb#1(main):001:0> jobs                     # list of subirbs
           #0->irb on main (#<Thread:0x400fb7e4> : stop)
           #1->irb#1 on main (#<Thread:0x40125d64> : running)
           irb#1(main):002:0> fg 0                     # switch job
           irb(main):002:0> class Foo;end
           irb(main):003:0> irb Foo                    # invoke subirb which has the
           #              context of Foo
           irb#2(Foo):001:0> def foo                   # define Foo#foo
           irb#2(Foo):002:1>   print 1
           irb#2(Foo):003:1> end
           irb#2(Foo):004:0> fg 0                      # switch job
           irb(main):004:0> jobs                       # list of job
           #0->irb on main (#<Thread:0x400fb7e4> : running)
           #1->irb#1 on main (#<Thread:0x40125d64> : stop)
           #2->irb#2 on Foo (#<Thread:0x4011d54c> : stop)
           irb(main):005:0> Foo.instance_methods       # Foo#foo is defined asurely
           irb(main):006:0> fg 2                       # switch job
           irb#2(Foo):005:0> def bar                   # define Foo#bar
           irb#2(Foo):006:1>  print "bar"
           irb#2(Foo):007:1> end
           irb#2(Foo):010:0>  Foo.instance_methods
           ["bar", "foo"]
           irb#2(Foo):011:0> fg 0
           irb(main):007:0> f =
           irb(main):008:0> irb f                      # invoke subirb which has the
           #  context of f (instance of Foo)
           irb#3(#<Foo:0x4010af3c>):001:0> jobs
           #0->irb on main (#<Thread:0x400fb7e4> : stop)
           #1->irb#1 on main (#<Thread:0x40125d64> : stop)
           #2->irb#2 on Foo (#<Thread:0x4011d54c> : stop)
           #3->irb#3 on #<Foo:0x4010af3c> (#<Thread:0x4010a1e0> : running)
           irb#3(#<Foo:0x4010af3c>):002:0> foo         # evaluate
           irb#3(#<Foo:0x4010af3c>):003:0> bar         # evaluate
           irb#3(#<Foo:0x4010af3c>):004:0> kill 1, 2, 3# kill job
           irb(main):009:0> jobs
           #0->irb on main (#<Thread:0x400fb7e4> : running)
           irb(main):010:0> exit                       # exit


       Because irb evaluates the inputs immediately after the imput is  syntactically  completed,
       irb  gives slight different result than directly use ruby. Known difference is pointed out

Declaration of the local variable

       The following causes an error in ruby:

           eval "foo = 0"
           -:2: undefined local variable or method `foo' for #<Object:0x40283118> (NameError)

       Though, the above will successfully done by irb.

           >> eval "foo = 0"
           => 0
           >> foo
           => 0

       Ruby evaluates a code after reading entire of code and determination of the scope of local
       variables. On the other hand, irb do immediately. More precisely, irb evaluate at first

           evel "foo = 0"

       then  foo is defined on this timing. It is because of this incompatibility.  If you'd like
       to detect those differences, begin...end can be used:

           >> begin
           ?>   eval "foo = 0"
           >>   foo
           >> end
           NameError: undefined local variable or method `foo' for #<Object:0x4013d0f0>
           (irb_local_binding):1:in `eval'


       Implementation of Here-document is incomplete.


       Irb can not always recognize a symbol as to be  Symbol.  Concretely,  an  expression  have
       completed, however Irb regard it as continuation line.

                                            April 2007                                 JIRB1.3(1)