added input_stack support to Pry

input_stack allows Pry instances to seemlessly continue reading input from other input objects on the stack when the current object generates EOF
Useful when you need to temporarily divert reading to another object and then switch back to another object

lib/pry/config.rb

@@ -37,6 +37,13 @@ class Pry
     #     :after_session => proc { puts "goodbye" }
     attr_accessor :hooks
 
+    # Get/Set the stack of input objects that a Pry instance switches
+    # to when its current input object encounters EOF.
+    # @return [Array] The array of input objects.
+    # @example
+    #   Pry.config.input_stack = [StringIO.new("puts 'hello world'\nexit")]
+    attr_accessor :input_stack
+
     # Get the array of Procs to be used for the prompts by default by
     # all Pry instances.
     # @return [Array<Proc>] The array of Procs to be used for the

lib/pry/pry_class.rb

@@ -51,7 +51,7 @@ class Pry
     def_delegators :@plugin_manager, :plugins, :load_plugins, :locate_plugins
 
     delegate_accessors :@config, :input, :output, :commands, :prompt, :print, :exception_handler,
-      :hooks, :color, :pager, :editor, :memory_size
+      :hooks, :color, :pager, :editor, :memory_size, :input_stack
   end
 
   # Load the rc files given in the `Pry::RC_FILES` array.
@@ -95,12 +95,11 @@ class Pry
     new(options).repl(target)
   end
 
-  # A version of `Pry.view` that clips the output to `max_length` chars.
+  # An inspector that clips the output to `max_length` chars.
   # In case of > `max_length` chars the `#<Object...> notation is used.
   # @param obj The object to view.
   # @param max_length The maximum number of chars before clipping occurs.
   # @return [String] The string representation of `obj`.
-  #
   def self.view_clip(obj, max_length = 60)
     if obj.kind_of?(Module) && obj.name.to_s != "" && obj.name.to_s.length <= max_length
       obj.name.to_s
@@ -184,6 +183,7 @@ class Pry
     config.exception_handler = DEFAULT_EXCEPTION_HANDLER
     config.exception_window_size = 5
     config.hooks = DEFAULT_HOOKS
+    config.input_stack = []
     config.color = true
     config.pager = true
     config.editor = default_editor_for_platform

lib/pry/pry_instance.rb

@@ -8,6 +8,8 @@ class Pry
   attr_accessor :print
   attr_accessor :exception_handler
   attr_accessor :hooks
+  attr_accessor :input_stack
+
   attr_accessor :custom_completions
 
   attr_accessor :binding_stack
@@ -20,6 +22,7 @@ class Pry
   attr_reader :input_array
   attr_reader :output_array
 
+
   # Create a new `Pry` object.
   # @param [Hash] options The optional configuration parameters.
   # @option options [#readline] :input The object to use for input.
@@ -45,7 +48,7 @@ class Pry
     attributes = [
                    :input, :output, :commands, :print,
                    :exception_handler, :hooks, :custom_completions,
-                   :prompt, :memory_size
+                   :prompt, :memory_size, :input_stack
                  ]
 
     attributes.each do |attribute|
@@ -140,7 +143,7 @@ class Pry
     exec_hook :before_session, output, target, self
     initialize_special_locals(target)
 
-    @input_array << nil # add empty input so inp and out match
+    @input_array << nil # add empty input so _in_ and _out_ match
 
     Pry.active_sessions += 1
     binding_stack.push target
@@ -400,7 +403,7 @@ class Pry
         end
 
       rescue EOFError
-        self.input = Pry.input
+        self.input = input_stack.empty? ? Pry.config.input : input_stack.pop
         ""
       end
     end

test/test_input_stack.rb

@@ -0,0 +1,27 @@
+require 'helper'
+
+describe "Pry#input_stack" do
+  it 'should accept :input_stack as a config option' do
+    stack = [StringIO.new("test")]
+    Pry.new(:input_stack => stack).input_stack.should == stack
+  end
+
+  it 'should use defaults from Pry.config' do
+    Pry.config.input_stack = [StringIO.new("exit")]
+    Pry.new.input_stack.should == Pry.config.input_stack
+    Pry.config.input_stack = []
+  end
+
+  it 'should read from all input objects on stack and exit session' do
+    stack = [b = StringIO.new(":cloister\nexit\n"), c = StringIO.new(":baron\n")]
+    instance = Pry.new(:input => StringIO.new(":alex\n"),
+                       :output => str_output = StringIO.new,
+                       :input_stack => stack)
+
+    instance.repl
+    str_output.string.should =~ /:alex/
+    str_output.string.should =~ /:baron/
+    str_output.string.should =~ /:cloister/
+  end
+
+end