IRb: how to start an interactive ruby session with pre-loaded classes

As I am going through my journey by adopting the Ruby language, I spend a lot of time inside IRb. It's just fantastic! But, as I am not very aware of it's capabilities, and still a “nubby” with Ruby, I would like to know the following:

• How can I “flush” the session, without restarting IRb (or is this not possible).
• How can I configure IRb to load a bunch of source files "hello.rb" and "hello_objects.rb", i.e. at startup? I am heavily working in these and it would be nice to know a short hand to load开发者_C百科 these classes, without manually typing 'load' for each again.

I'm not sure it's possible to 'flush' a session. However, you can load your classes like this:

irb -r 'hello.rb' -r 'hello_objects.rb'

You can manage sessions in irb. Start irb and try this:

x=1
irb     # Opens a new session
puts x  # error
jobs    # lists sessions
quit    # kills current session
puts x  # 1

There is also the command "fg (number)" which switches between sessions. See: http://tagaholic.me/2009/05/11/demystifying-irb-commands.html

I believe what you're looking for is modifying your ~/.irbrc file. It was mentioned earlier, but no examples given. Here is a short example of requiring some common utilities you may want in your irb session:

# Print to yaml format with "y"
require 'yaml'
# Pretty printing
require 'pp'
# Ability to load rubygem modules
require 'rubygems'
# Tab completion
require 'irb/completion'

You can put any ruby code into your ~/.irbrc file, which will get evaluated whenever you run irb. In this case your require statements.

These are not direct answers but can apply to your desire to understand irb more.

A number of "irb" methods are available to the console object.

methods.grep(/irb/).sort
=> ["irb", "irb_bindings", "irb_cb", "irb_change_binding", "irb_change_workspace",
"irb_chws", "irb_context", "irb_current_working_binding", "irb_current_working_workspace",
"irb_cwb", "irb_cws", "irb_cwws", "irb_exit", "irb_fg", "irb_jobs", "irb_kill", "irb_load",
"irb_pop_binding", "irb_pop_workspace", "irb_popb", "irb_popws", "irb_print_working_binding",
"irb_print_working_workspace", "irb_push_binding", "irb_push_workspace", "irb_pushb",
"irb_pushws", "irb_pwb", "irb_pwws", "irb_quit", "irb_require", "irb_source", "irb_workspaces"]

Have some fun playing around with those.

Another is the "conf" object that gives feedback about your irb environment:

conf
=> conf.ap_name="irb"
conf.auto_indent_mode=false
conf.back_trace_limit=16
conf.debug_level=1
conf.echo=true
conf.ignore_eof=false
conf.ignore_sigint=true
conf.inspect_mode=nil
conf.io=#<IRB::StdioInputMethod:0x79da0>
conf.irb=#<IRB::Irb:0x7c58c>
conf.irb_name="irb"
conf.irb_path="(irb)"
conf.last_value=...
conf.line_no=6
conf.load_modules=[]
conf.prompt_c="%N(%m):%03n:%i* "
conf.prompt_i="%N(%m):%03n:%i> "
conf.prompt_mode=:DEFAULT
conf.prompt_s="%N(%m):%03n:%i%l "
conf.rc=true
conf.return_format="=> %s\n"
conf.thread=#<Thread:0x31790 run>
conf.use_readline=false
conf.verbose=nil
conf.workspace=#<IRB::WorkSpace:0x7aa84 @main=main, @binding=#<Binding:0x7a2a0>>