Class: IRB::Inspector

Inherits:
Object show all
Defined in:
lib/irb/inspector.rb

Overview

An irb inspector

In order to create your own custom inspector there are two things you should be aware of:

Inspector uses #inspect_value, or inspect_proc, for output of return values.

This also allows for an optional #init+, or init_proc, which is called when the inspector is activated.

Knowing this, you can create a rudimentary inspector as follows:

irb(main):001:0> ins = IRB::Inspector.new(proc{ |v| "omg! #{v}" })
irb(main):001:0> IRB.CurrentContext.inspect_mode = ins # => omg! #<IRB::Inspector:0x007f46f7ba7d28>
irb(main):001:0> "what?" #=> omg! what?

Constant Summary collapse

KERNEL_INSPECT = 
Object.instance_method(:inspect)
INSPECTORS =

Default inspectors available to irb, this includes:

:pp

Using Kernel#pretty_inspect

:yaml

Using YAML.dump

:marshal

Using Marshal.dump

{}

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(inspect_proc, init_proc = nil) ⇒ Inspector

Creates a new inspector object, using the given inspect_proc when output return values in irb.



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# File 'lib/irb/inspector.rb', line 83

def initialize(inspect_proc, init_proc = nil)
  @init = init_proc
  @inspect = inspect_proc
end

Class Method Details

.def_inspector(key, arg = nil, &block) ⇒ Object

Example

Inspector.def_inspector(key, init_p=nil){|v| v.inspect}
Inspector.def_inspector([key1,..], init_p=nil){|v| v.inspect}
Inspector.def_inspector(key, inspector)
Inspector.def_inspector([key1,...], inspector)



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# File 'lib/irb/inspector.rb', line 58

def self.def_inspector(key, arg=nil, &block)
  if block_given?
    inspector = IRB::Inspector(block, arg)
  else
    inspector = arg
  end

  case key
  when Array
    for k in key
      def_inspector(k, inspector)
    end
  when Symbol
    INSPECTORS[key] = inspector
    INSPECTORS[key.to_s] = inspector
  when String
    INSPECTORS[key] = inspector
    INSPECTORS[key.intern] = inspector
  else
    INSPECTORS[key] = inspector
  end
end

.keys_with_inspector(inspector) ⇒ Object

Determines the inspector to use where inspector is one of the keys passed during inspector definition.



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# File 'lib/irb/inspector.rb', line 48

def self.keys_with_inspector(inspector)
  INSPECTORS.select{|k,v| v == inspector}.collect{|k, v| k}
end

Instance Method Details

#init ⇒ Object

Proc to call when the inspector is activated, good for requiring dependent libraries.



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# File 'lib/irb/inspector.rb', line 90

def init
  @init.call if @init
end

#inspect_value(v) ⇒ Object

Proc to call when the input is evaluated and output in irb.



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# File 'lib/irb/inspector.rb', line 95

def inspect_value(v)
  @inspect.call(v)
rescue => e
  puts "An error occurred when inspecting the object: #{e.inspect}"

  begin
    puts "Result of Kernel#inspect: #{KERNEL_INSPECT.bind_call(v)}"
    ''
  rescue => e
    puts "An error occurred when running Kernel#inspect: #{e.inspect}"
    puts e.backtrace.join("\n")
    ''
  end
end