Sean Busbey created HBASE-11686:
-----------------------------------

             Summary: Shell code should create a binding / irb workspace 
instead of polluting the root namespace
                 Key: HBASE-11686
                 URL: https://issues.apache.org/jira/browse/HBASE-11686
             Project: HBase
          Issue Type: Improvement
            Reporter: Sean Busbey
            Priority: Minor


Right now, the shell builds a list of commands and then injects them into the 
root exectution's context

bin/hirb.rb
{code}
# Add commands to this namespace
@shell.export_commands(self)
{code}

hbase-shell/src/main/ruby/shell.rb
{code}
    def export_commands(where)
      ::Shell.commands.keys.each do |cmd|
        # here where is the IRB namespace
        # this method just adds the call to the specified command
        # which just references back to 'this' shell object
        # a decently extensible way to add commands
        where.send :instance_eval, <<-EOF
          def #{cmd}(*args)
            ret = @shell.command('#{cmd}', *args)
            puts
            return ret
          end
        EOF
      end
    end
{code}

This is an unclean abstraction. For one, it requires that there be an instance 
variable in the main namespace called '@shell' without making that clear in the 
docs. Additionally, it complicates maintenance by breaking isolation.

We should update things so that shell can provide a binding for eval or a 
workspace for IRB execution and then use it directly when we construct our IRB 
session.



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