input becomes primary argument in #initialize.

with `_pry_` as an optional second. in the repl the second argument will
always be met but to avoid needing a pry instance around to use Pry::InputCompleter,
it uses the first argument(`input`) when implementing auto completion, and
'pry' can be used if its around/available.

lib/pry/input_completer.rb

@@ -1,7 +1,6 @@
 # taken from irb
 # Implements tab completion for Readline in Pry
 class Pry::InputCompleter
-
   NUMERIC_REGEXP            = /^(-?(0[dbo])?[0-9_]+(\.[0-9_]+)?([eE]-?[0-9]+)?)\.([^.]*)$/
   ARRAY_REGEXP              = /^([^\]]*\])\.([^.]*)$/
   SYMBOL_REGEXP             = /^(:[^:.]*)$/
@@ -42,13 +41,9 @@ class Pry::InputCompleter
 
   WORD_ESCAPE_STR = " \t\n\"\\'`><=;|&{("
 
-  def initialize(pry = nil)
-    if pry
-      @pry = pry
-      @input = pry.input
-    else
-      @input = Readline
-    end
+  def initialize(input, pry = nil)
+    @pry = pry if pry
+    @input = input
     @input.basic_word_break_characters = WORD_ESCAPE_STR if @input.respond_to?(:basic_word_break_characters=)
     @input.completion_append_character = nil if @input.respond_to?(:completion_append_character=)
   end

lib/pry/pry_instance.rb

@@ -127,7 +127,8 @@ class Pry
   def complete(input)
     return EMPTY_COMPLETIONS unless config.completer
     Pry.critical_section do
-      completer = config.completer.new(self)
+      completer = config.completer.new(input, self)
+      # todo: `input` argument isn't needed.
       completer.call input, target: current_binding, custom_completions: custom_completions.call.push(*sticky_locals.keys)
     end
   end

spec/completion_spec.rb

@@ -4,7 +4,7 @@ require "pry/input_completer"
 
 def completer_test(bind, pry=nil, assert_flag=true)
   test = proc {|symbol|
-    Pry::InputCompleter.new(pry).call(symbol[0..-2], :target => Pry.binding_for(bind)).include?(symbol).should  == assert_flag}
+    Pry::InputCompleter.new(pry || Readline, pry).call(symbol[0..-2], :target => Pry.binding_for(bind)).include?(symbol).should  == assert_flag}
   return proc {|*symbols| symbols.each(&test) }
 end
 
@@ -30,12 +30,12 @@ describe Pry::InputCompleter do
   # another jruby hack :((
   if !Pry::Helpers::BaseHelpers.jruby?
     it "should not crash if there's a Module that has a symbolic name." do
-      lambda{ Pry::InputCompleter.new.call "a.to_s.", :target => Pry.binding_for(Object.new) }.should.not.raise Exception
+      lambda{ Pry::InputCompleter.new(Readline).call "a.to_s.", :target => Pry.binding_for(Object.new) }.should.not.raise Exception
     end
   end
 
   it 'should take parenthesis and other characters into account for symbols' do
-    lambda { Pry::InputCompleter.new.call(":class)", :target => Pry.binding_for(Object.new)) }.should.not.raise(RegexpError)
+    lambda { Pry::InputCompleter.new(Readline).call(":class)", :target => Pry.binding_for(Object.new)) }.should.not.raise(RegexpError)
   end
 
   it 'should complete instance variables' do
@@ -114,7 +114,7 @@ describe Pry::InputCompleter do
     completer_test(binding).call('o.foo')
 
     # trailing slash
-    Pry::InputCompleter.new.call('Mod2/', :target => Pry.binding_for(Mod)).include?('Mod2/').should   == true
+    Pry::InputCompleter.new(Readline).call('Mod2/', :target => Pry.binding_for(Mod)).include?('Mod2/').should   == true
   end
 
   it 'should complete for arbitrary scopes' do
@@ -185,7 +185,7 @@ describe Pry::InputCompleter do
     completer_test(binding).call('o.foo')
 
     # trailing slash
-    Pry::InputCompleter.new.call('Mod2/', :target => Pry.binding_for(Mod)).include?('Mod2/').should   == true
+    Pry::InputCompleter.new(Readline).call('Mod2/', :target => Pry.binding_for(Mod)).include?('Mod2/').should   == true
   end
 
   it 'should complete for arbitrary scopes' do
@@ -209,6 +209,6 @@ describe Pry::InputCompleter do
 
   it 'should not return nil in its output' do
     pry = Pry.new
-    Pry::InputCompleter.new(pry).call("pry.", :target => binding).should.not.include nil
+    Pry::InputCompleter.new(Readline, pry).call("pry.", :target => binding).should.not.include nil
   end
 end