Returns the current version of IRB, including release version and last updated date.
# File lib/irb.rb, line 357
def IRB.version
if v = @CONF[:VERSION] then return v end
require "irb/version"
rv = @RELEASE_VERSION.sub(/\.0/, "")
@CONF[:VERSION] = format("irb %s(%s)", rv, @LAST_UPDATE_DATE)
end
