diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9a53497..dc1ac0c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,7 +3,43 @@
 All notable changes to this project will be documented in this file.
 This project adheres to [Semantic Versioning](http://semver.org/).
 
-**View all [Unreleased][] changes here**
+## [1.2.2][]
+#### Changed
+-   Minor improvement to logic in `AbstractInputHandler::validateInput()`. Ensures that an input with a validator, but with a default value and no user suplied input, will have the default value used.
+
+## [1.2.1][]
+#### Changed
+-   Updated `InputHandlerFactory` and `InputTypeFactory` to work with changes in `pointybeard/helpers-foundation-factory` 1.0.2
+
+## [1.2.0][]
+#### Added
+-   Added `InputTypeFilterIterator` class
+-   Added `UnrecognisedInputException` exception
+
+#### Changed
+-   `InputCollection` now implements `Iterator` and `Countable` (implementing required methods)
+-   Removed use of `$type` in `InputCollection`
+-   Added `InputCollection::getItemsExcludeByType()`
+-   `InputCollection::getItemsByType()` and `InputCollection::getItems()` now returns an `Iterator`
+-   Renamed `InputCollection::append()` to `add()` and added `$position` flag
+-   Added `POSITION_APPEND` and `POSITION_PREPEND` flags to `InputCollection`
+-   Made `getCollection()`, `getInput()`, `find()`, and `validate()` in `AbstractInputHandler` final
+-   Removed all categorisation of items by type in `AbstractInputHandler::$input`
+-   Abstracted most of `AbstractInputHandler::validate()` into it's own protected method called `validateInput()`
+-   Removed `$skipValidation` argument from `AbstractInputHandler::bind()` and relaced with `$flags`
+-   Added `FLAG_BIND_SKIP_VALIDATION`, `FLAG_VALIDATION_SKIP_REQUIRED`, `FLAG_VALIDATION_SKIP_CUSTOM`, and `FLAG_VALIDATION_SKIP_UNRECOGNISED` flags to `AbstractInputHandler`
+-   Added check in `AbstractInputHandler::validate()` to look for unrecognised options and arguments
+-   Removed `InputHandlerFactory::FLAG_SKIP_VALIDATION` from `InputHandlerFactory`
+-   Passing flags in call from `InputHandlerFactory::build()` to `AbstractInputHandler::bind()`
+-   Updated `InputHandlerInterface::bind()` and `validate()` methods to support flags
+
+## [1.1.4][]
+#### Fixed
+-   Fixed misnamed variable in `InputCollection::merge()`
+
+## [1.1.3][]
+#### Fixed
+-   Fixed logic bug that prevented `$index` and `$type` from being set in `InputCollection::append()`. This means replaceing items in an `InputCollection` now works as expected
 
 ## [1.1.2][]
 #### Added
@@ -11,22 +47,22 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 -   Added `InputTypeInterface::getDisplayName()` method to standardise how the name of an `InputTypeInterface` class wants to display it's name
 
 #### Changed
--   Updated validation logic for inputs that have a validator, no default, and are not set.
+-   Updated validation logic for inputs that have a validator, no default, and are not set
 -   Throwing `InputValidationFailedException` exception when validation fails
 -   Updated `RequiredInputMissingException` and `RequiredInputMissingValueException` exceptions to use `InputTypeInterface::getDisplayName()` when producing their message
 -   Removed unused `RequiredArgumentMissingException` exception
 
 ## [1.1.1][]
 #### Changed
--   `AbstractInputHandler::find()` returns NULL if it cannot find any input with the supplied name. It is easier to test for NULL than it is to catch an exception.
+-   `AbstractInputHandler::find()` returns NULL if it cannot find any input with the supplied name. It is easier to test for NULL than it is to catch an exception
 
 ## [1.1.0][]
 #### Added
--   Expanded input types to include `Flag`, `IncrementingFlag`, and `LongOption`.
+-   Expanded input types to include `Flag`, `IncrementingFlag`, and `LongOption`
 -   Added `InputTypeFactory` to help with loading input type classes
 
 #### Changed
--   Updated to work with more than just `Argument` and `Option` input types. Makes use of `InputTypeFactory` to allow addition of new types as needed.
+-   Updated to work with more than just `Argument` and `Option` input types. Makes use of `InputTypeFactory` to allow addition of new types as needed
 
 ## [1.0.2][]
 #### Changed
@@ -45,7 +81,11 @@ This project adheres to [Semantic Versioning](http://semver.org/).
 #### Added
 -   Initial release
 
-[Unreleased]: https://github.com/pointybeard/helpers-functions-cli/compare/1.1.2...integration
+[1.2.2]: https://github.com/pointybeard/helpers-functions-cli/compare/1.2.1...1.2.2
+[1.2.1]: https://github.com/pointybeard/helpers-functions-cli/compare/1.2.0...1.2.1
+[1.2.0]: https://github.com/pointybeard/helpers-functions-cli/compare/1.1.4...1.2.0
+[1.1.4]: https://github.com/pointybeard/helpers-functions-cli/compare/1.1.3...1.1.4
+[1.1.3]: https://github.com/pointybeard/helpers-functions-cli/compare/1.1.2...1.1.3
 [1.1.2]: https://github.com/pointybeard/helpers-functions-cli/compare/1.1.1...1.1.2
 [1.1.1]: https://github.com/pointybeard/helpers-functions-cli/compare/1.1.0...1.1.1
 [1.1.0]: https://github.com/pointybeard/helpers-functions-cli/compare/1.0.3...1.1.0
diff --git a/README.md b/README.md
index d76ca83..be26831 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # PHP Helpers: Command-line Input and Input Type Handlers
 
--   Version: v1.1.2
--   Date: May 25 2019
+-   Version: v1.2.2
+-   Date: Aug 06 2019
 -   [Release notes](https://github.com/pointybeard/helpers-cli-input/blob/master/CHANGELOG.md)
 -   [GitHub repository](https://github.com/pointybeard/helpers-cli-input)
 
@@ -9,7 +9,7 @@ Collection of classes for handling argv (and other) input when calling command-l
 
 ## Installation
 
-This library is installed via [Composer](http://getcomposer.org/). To install, use `composer require pointybeard/helpers-cli-input` or add `"pointybeard/helpers-cli-input": "~1.1"` to your `composer.json` file.
+This library is installed via [Composer](http://getcomposer.org/). To install, use `composer require pointybeard/helpers-cli-input` or add `"pointybeard/helpers-cli-input": "~1.2.0"` to your `composer.json` file.
 
 And run composer to update your dependencies:
 
@@ -26,7 +26,7 @@ To include all the [PHP Helpers](https://github.com/pointybeard/helpers) package
 
 Include this library in your PHP files with `use pointybeard\Helpers\Cli`. See example code in `example/example.php`. The example code can be run with the following command:
 
-    php -f example/example.php -- -vvvs -d example/example.json import
+    php -f example/example.php -- -vvv -d example/example.json import
 
 ## Support
 
diff --git a/composer.json b/composer.json
index b7cf29b..8eea99b 100644
--- a/composer.json
+++ b/composer.json
@@ -1,6 +1,5 @@
 {
     "name": "pointybeard/helpers-cli-input",
-    "version": "1.1.2",
     "description": "Collection of classes for handling argv (and other) input when calling command-line scripts. Helps with parsing, collecting and validating arguments, options, and flags.",
     "homepage": "https://github.com/pointybeard/helpers-cli-input",
     "license": "MIT",
@@ -14,14 +13,8 @@
     ],
     "require": {
         "php": ">=7.2",
-        "pointybeard/helpers-foundation-factory": "~1",
-        "pointybeard/helpers-functions-flags": "~1"
-    },
-    "require-dev": {
-        "phpunit/phpunit": "^8",
-        "pointybeard/helpers-functions-strings": "^1",
-        "pointybeard/helpers-cli-colour": "^1",
-        "pointybeard/helpers-functions-cli": "^1"
+        "pointybeard/helpers-foundation-factory": "~1.0",
+        "pointybeard/helpers-functions-flags": "~1.0"
     },
     "support": {
         "issues": "https://github.com/pointybeard/helpers-cli-input/issues",
diff --git a/example/example.php b/example/example.php
index 6f2ac71..1695bf1 100644
--- a/example/example.php
+++ b/example/example.php
@@ -4,18 +4,17 @@ declare(strict_types=1);
 include __DIR__.'/../vendor/autoload.php';
 
 use pointybeard\Helpers\Cli\Input;
-use pointybeard\Helpers\Cli\Colour\Colour;
 use pointybeard\Helpers\Functions\Cli;
 
 // Define what we are expecting to get from the command line
 $collection = (new Input\InputCollection())
-    ->append(
+    ->add(
         Input\InputTypeFactory::build('Argument')
             ->name('action')
             ->flags(Input\AbstractInputType::FLAG_REQUIRED)
             ->description('The name of the action to perform')
     )
-    ->append(
+    ->add(
         Input\InputTypeFactory::build('IncrementingFlag')
             ->name('v')
             ->flags(Input\AbstractInputType::FLAG_OPTIONAL | Input\AbstractInputType::FLAG_TYPE_INCREMENTING)
@@ -23,11 +22,11 @@ $collection = (new Input\InputCollection())
             ->validator(new Input\Validator(
                 function (Input\AbstractInputType $input, Input\AbstractInputHandler $context) {
                     // Make sure verbosity level never goes above 3
-                    return min(3, (int)$context->find('v'));
+                    return min(3, (int) $context->find('v'));
                 }
             ))
     )
-    ->append(
+    ->add(
         Input\InputTypeFactory::build('LongOption')
             ->name('data')
             ->short('d')
@@ -57,51 +56,19 @@ $collection = (new Input\InputCollection())
 
 // Get the supplied input. Passing the collection will make the handler bind values
 // and validate the input according to our collection
-try{
+try {
     $argv = Input\InputHandlerFactory::build('Argv', $collection);
-} catch(\Exception $ex) {
-    echo "Error when attempting to bind values to collection. Returned: " . $ex->getMessage() . PHP_EOL;
+} catch (\Exception $ex) {
+    echo 'Error when attempting to bind values to collection. Returned: '.$ex->getMessage().PHP_EOL;
     exit;
 }
 
-// Display the manual in green text
-echo Cli\manpage(
-    basename(__FILE__),
-    '1.0.2',
-    'An example script for the PHP Helpers: Command-line Input and Input Type Handlers composer library (pointybeard/helpers-cli-input).',
-    $collection,
-    Colour::FG_GREEN,
-    Colour::FG_WHITE,
-    [
-        'Examples' => 'php -f example/example.php -- -vvv -d example/example.json import'
-    ]
-).PHP_EOL.PHP_EOL;
-
-// example.php 1.0.2, An example script for the PHP Helpers: Command-line Input
-// and Input Type Handlers composer library (pointybeard/helpers-cli-input).
-// Usage: example.php [OPTIONS]... ACTION...
-//
-// Arguments:
-// ACTION              The name of the action to perform
-//
-// Options:
-// -v                            verbosity level. -v (errors only), -vv
-//                               (warnings and errors), -vvv (everything).
-// -d, --data=VALUE              Path to the input JSON data
-//
-// Examples:
-// php -f example/example.php -- -vvvs -d example/example.json import
-
-
 var_dump($argv->find('action'));
 // string(6) "import"
 
 var_dump($argv->find('v'));
 //int(3)
 
-var_dump($argv->find('s'));
-//bool(true)
-
 var_dump($argv->find('data'));
 // class stdClass#11 (1) {
 //   public $fruit =>
diff --git a/src/Input/AbstractInputHandler.php b/src/Input/AbstractInputHandler.php
index cb1a799..e0c5e13 100644
--- a/src/Input/AbstractInputHandler.php
+++ b/src/Input/AbstractInputHandler.php
@@ -5,15 +5,40 @@ declare(strict_types=1);
 namespace pointybeard\Helpers\Cli\Input;
 
 use pointybeard\Helpers\Functions\Flags;
+use pointybeard\Helpers\Functions\Debug;
 
 abstract class AbstractInputHandler implements Interfaces\InputHandlerInterface
 {
+    /**
+     * Will skip all validation when bind() is executed. Ignores all other flags
+     * @var integer
+     */
+    const FLAG_BIND_SKIP_VALIDATION = 0x0001;
+
+    /**
+     * Will skip the required input and required values check
+     * @var integer
+     */
+    const FLAG_VALIDATION_SKIP_REQUIRED = 0x0002;
+
+    /**
+     * Will skip running custom validators
+     * @var integer
+     */
+    const FLAG_VALIDATION_SKIP_CUSTOM = 0x0004;
+
+    /**
+     * Will skip checking if an input is in the collection
+     * @var integer
+     */
+    const FLAG_VALIDATION_SKIP_UNRECOGNISED = 0x0008;
+
     protected $input = [];
     protected $collection = null;
 
     abstract protected function parse(): bool;
 
-    public function bind(InputCollection $inputCollection, bool $skipValidation = false): bool
+    final public function bind(InputCollection $inputCollection, ?int $flags = null): bool
     {
         // Do the binding stuff here
         $this->input = [];
@@ -21,8 +46,8 @@ abstract class AbstractInputHandler implements Interfaces\InputHandlerInterface
 
         $this->parse();
 
-        if (true !== $skipValidation) {
-            $this->validate();
+        if (!Flags\is_flag_set($flags, self::FLAG_BIND_SKIP_VALIDATION)) {
+            $this->validate($flags);
         }
 
         return true;
@@ -39,71 +64,86 @@ abstract class AbstractInputHandler implements Interfaces\InputHandlerInterface
         }
     }
 
-    public function validate(): void
-    {
-        foreach ($this->collection->getItems() as $type => $items) {
-            foreach($items as $input) {
-                self::checkRequiredAndRequiredValue($input, $this->input);
+    protected function validateInput(AbstractInputType $input, ?int $flags) {
+        if(!Flags\is_flag_set($flags, self::FLAG_VALIDATION_SKIP_REQUIRED)) {
+            self::checkRequiredAndRequiredValue($input, $this->input);
+        }
+        // There is a default value and input has not been set. Assign the
+        // default value to the result.
+        if (
+            null !== $input->default() &&
+            null === $this->find($input->name())
+        ) {
+            $result = $input->default();
 
-                // There is a default value, input has not been set, and there
-                // is no validator
-                if(
-                    null !== $input->default() &&
-                    null === $this->find($input->name()) &&
-                    null === $input->validator()
-                ) {
-                    $result = $input->default();
+        // Input has been set AND it has a validator. Run the validator over the
+        // input. Note, this will be skipped if FLAG_VALIDATION_SKIP_CUSTOM is
+        // set
+        } elseif (null !== $this->find($input->name()) && null !== $input->validator() && !Flags\is_flag_set($flags, self::FLAG_VALIDATION_SKIP_CUSTOM)) {
+            $validator = $input->validator();
 
-                // Input has been set and it has a validator
-                } elseif(null !== $this->find($input->name()) && null !== $input->validator()) {
-                    $validator = $input->validator();
-
-                    if ($validator instanceof \Closure) {
-                        $validator = new Validator($validator);
-                    } elseif (!($validator instanceof Validator)) {
-                        throw new \Exception("Validator for '{$input->name()}' must be NULL or an instance of either Closure or Input\Validator.");
-                    }
-
-                    try {
-                        $result = $validator->validate($input, $this);
-                    } catch(\Exception $ex) {
-                        throw new Exceptions\InputValidationFailedException($input, 0, $ex);
-                    }
-
-                // No default, no validator, but may or may not have been set
-                } else {
-                    $result = $this->find($input->name());
-                }
-
-                $this->input[$input->name()] = $result;
+            if ($validator instanceof \Closure) {
+                $validator = new Validator($validator);
+            } elseif (!($validator instanceof Validator)) {
+                throw new \Exception("Validator for '{$input->name()}' must be NULL or an instance of either Closure or Input\Validator.");
             }
+
+            try {
+                $result = $validator->validate($input, $this);
+            } catch (\Exception $ex) {
+                throw new Exceptions\InputValidationFailedException($input, 0, $ex);
+            }
+
+        // No default, but may or may not have been set so assign whatever value
+        // it might have to the result
+        } else {
+            $result = $this->find($input->name());
+        }
+
+        return $result;
+    }
+
+    protected function isInputRecognised(string $name): bool {
+        return null === $this->collection->find($name) ? false : true;
+    }
+
+    final public function validate(?int $flags = null): void
+    {
+        if(!Flags\is_flag_set($flags, self::FLAG_VALIDATION_SKIP_UNRECOGNISED)) {
+            foreach($this->input as $name => $value) {
+                if(false == static::isInputRecognised((string)$name)) {
+                    throw new Exceptions\UnrecognisedInputException("'{$name}' is not recognised");
+                }
+            }
+        }
+
+        foreach ($this->collection->getItems() as $input) {
+            $this->input[$input->name()] = static::validateInput($input, $flags);
         }
     }
 
-    public function find(string $name)
+    final public function find(string $name)
     {
-        if(isset($this->input[$name])) {
+        if (isset($this->input[$name])) {
             return $this->input[$name];
         }
 
         // Check the collection to see if anything responds to $name
-        foreach($this->collection->getItems() as $type => $items) {
-            foreach($items as $ii) {
-                if($ii->respondsTo($name) && isset($this->input[$ii->name()])) {
-                    return $this->input[$ii->name()];
-                }
+        foreach ($this->collection->getItems() as $item) {
+            if ($item->respondsTo($name) && isset($this->input[$item->name()])) {
+                return $this->input[$item->name()];
             }
         }
 
         return null;
     }
 
-    public function getInput(): array
+    final public function getInput(): array
     {
         return $this->input;
     }
 
-    public function getCollection(): ?InputCollection
+    final public function getCollection(): ?InputCollection
     {
         return $this->collection;
     }
diff --git a/src/Input/AbstractInputType.php b/src/Input/AbstractInputType.php
index be3999c..0d5f1af 100644
--- a/src/Input/AbstractInputType.php
+++ b/src/Input/AbstractInputType.php
@@ -25,7 +25,7 @@ abstract class AbstractInputType implements Interfaces\InputTypeInterface
         $this->default = $default;
     }
 
-    public function __call($name, array $args=[])
+    public function __call($name, array $args = [])
     {
         if (empty($args)) {
             return $this->$name;
@@ -43,7 +43,7 @@ abstract class AbstractInputType implements Interfaces\InputTypeInterface
 
     public function respondsTo(string $name): bool
     {
-        return ($name == $this->name);
+        return $name == $this->name;
     }
 
     public function getType(): string
diff --git a/src/Input/Exceptions/InputValidationFailedException.php b/src/Input/Exceptions/InputValidationFailedException.php
index fe3fe81..6c3414c 100644
--- a/src/Input/Exceptions/InputValidationFailedException.php
+++ b/src/Input/Exceptions/InputValidationFailedException.php
@@ -3,12 +3,13 @@
 declare(strict_types=1);
 
 namespace pointybeard\Helpers\Cli\Input\Exceptions;
+
 use pointybeard\Helpers\Cli\Input\AbstractInputType;
 
 class InputValidationFailedException extends \Exception
 {
     public function __construct(AbstractInputType $input, $code = 0, \Exception $previous = null)
     {
-        return parent::__construct(sprintf("Validation failed for %s. Returned: %s", $input->getDisplayName(), $previous->getMessage()), $code, $previous);
+        return parent::__construct(sprintf('Validation failed for %s. Returned: %s', $input->getDisplayName(), $previous->getMessage()), $code, $previous);
     }
 }
diff --git a/src/Input/Exceptions/RequiredInputMissingValueException.php b/src/Input/Exceptions/RequiredInputMissingValueException.php
index 03f97a8..62be79b 100644
--- a/src/Input/Exceptions/RequiredInputMissingValueException.php
+++ b/src/Input/Exceptions/RequiredInputMissingValueException.php
@@ -18,7 +18,6 @@ class RequiredInputMissingValueException extends \Exception
             'a value is required for %s',
             $input->getDisplayName()
         ), $code, $previous);
-
     }
 
     public function getInput(): Input\AbstractInputType
diff --git a/src/Input/Exceptions/UnrecognisedInputException.php b/src/Input/Exceptions/UnrecognisedInputException.php
new file mode 100644
index 0000000..22258f4
--- /dev/null
+++ b/src/Input/Exceptions/UnrecognisedInputException.php
@@ -0,0 +1,9 @@
+<?php
+
+declare(strict_types=1);
+
+namespace pointybeard\Helpers\Cli\Input\Exceptions;
+
+class UnrecognisedInputException extends \Exception
+{
+}
diff --git a/src/Input/Handlers/Argv.php b/src/Input/Handlers/Argv.php
index 536284c..5b79b6c 100644
--- a/src/Input/Handlers/Argv.php
+++ b/src/Input/Handlers/Argv.php
@@ -3,9 +3,10 @@
 declare(strict_types=1);
 
 namespace pointybeard\Helpers\Cli\Input\Handlers;
-
+use pointybeard\Helpers\Cli\Input\Exceptions;
 use pointybeard\Helpers\Cli\Input;
 use pointybeard\Helpers\Functions\Flags;
+use pointybeard\Helpers\Functions\Debug;
 
 class Argv extends Input\AbstractInputHandler
 {
@@ -61,9 +62,31 @@ class Argv extends Input\AbstractInputHandler
         return $result;
     }
 
+    protected function findOptionInCollection(string $name): ?Input\AbstractInputType
+    {
+        $option = $this->collection->find($name);
+        if(!($option instanceof Input\AbstractInputType)) {
+            return null;
+        }
+
+        return $option;
+    }
+
+    protected function findArgumentInCollection(int $index, string $token): ?Input\AbstractInputType
+    {
+        $arguments = $this->collection->getItemsByType('Argument');
+        $position = 0;
+        foreach($arguments as $a) {
+            if($position == $index) {
+                return $a;
+            }
+            $position++;
+        }
+        return null;
+    }
+
     protected function parse(): bool
     {
-        // So some parsing here.
         $it = new \ArrayIterator($this->argv);
 
         $position = 0;
@@ -83,7 +106,7 @@ class Argv extends Input\AbstractInputHandler
                         $value = true;
                     }
 
-                    $o = $this->collection->find($name);
+                    $o = $this->findOptionInCollection($name);
 
                     $this->input[
                         $o instanceof Input\AbstractInputType
@@ -99,7 +122,7 @@ class Argv extends Input\AbstractInputHandler
                     // Determine if we're expecting a value.
                     // It also might have a long option equivalent, so we need
                     // to look for that too.
-                    $o = $this->collection->find($name);
+                    $o = $this->findOptionInCollection($name);
 
                     // This could also be an incrementing value
                     // and needs to be added up. E.g. e.g. -vvv or -v -v -v
@@ -142,13 +165,14 @@ class Argv extends Input\AbstractInputHandler
                     // Arguments are positional, so we need to keep a track
                     // of the index and look at the collection for an argument
                     // with the same index
-                    $a = $this->collection->getItemByIndex('Argument', $argumentCount);
+                    $a = $this->findArgumentInCollection($argumentCount, $token);
+
                     $this->input[
                         $a instanceof Input\AbstractInputType
                             ? $a->name()
                             : $argumentCount
                     ] = $token;
-                    $argumentCount++;
+                    ++$argumentCount;
                     break;
             }
             $it->next();
diff --git a/src/Input/InputCollection.php b/src/Input/InputCollection.php
index d307217..49db36f 100644
--- a/src/Input/InputCollection.php
+++ b/src/Input/InputCollection.php
@@ -4,96 +4,150 @@ declare(strict_types=1);
 
 namespace pointybeard\Helpers\Cli\Input;
 
-class InputCollection
+class InputCollection implements \Iterator, \Countable
 {
     private $items = [];
+    private $position = 0;
+
+    public const POSITION_APPEND = 0x0001;
+    public const POSITION_PREPEND = 0x0002;
 
     // Prevents the class from being instanciated
     public function __construct()
     {
+        $this->position = 0;
     }
 
-    public function append(Interfaces\InputTypeInterface $input, bool $replace = false): self
+    public function current(): mixed
     {
-        $class = new \ReflectionClass($input);
+        return $this->items[$this->position];
+    }
 
-        $index = null;
-        $type = null;
+    public function key(): scalar
+    {
+        return $this->position;
+    }
 
-        if (!$replace && null !== $this->find($input->name(), null, null, $index, $type)) {
-            throw new \Exception("{$class->getShortName()} '{$input->name()}' already exists in this collection");
+    public function next(): void
+    {
+        ++$this->position;
+    }
+
+    public function rewind(): void
+    {
+        $this->position = 0;
+    }
+
+    public function valid(): bool
+    {
+        return isset($this->items[$this->position]);
+    }
+
+    public function count() : int {
+        return count($this->items);
+    }
+
+    public function exists(string $name, &$index=null): bool {
+        return (null !== $this->find($name, null, null, $index));
+    }
+
+    public function remove(string $name): self {
+        if(!$this->exists($name, $index)) {
+            throw new \Exception("Input '{$name}' does not exist in this collection");
+        }
+        unset($this->items[$index]);
+        return $this;
+    }
+
+    public function add(Interfaces\InputTypeInterface $input, bool $replace = false, int $position=self::POSITION_APPEND): self
+    {
+        if($this->exists($input->name(), $index) && !$replace) {
+            throw new \Exception(
+                (new \ReflectionClass($input))->getShortName()." '{$input->name()}' already exists in this collection"
+            );
         }
 
         if (true == $replace && null !== $index) {
-            $this->items[$class->getShortName()][$index] = $argument;
+            $this->items[$index] = $input;
         } else {
-            $this->items[$class->getShortName()][] = $input;
+            if($position == self::POSITION_PREPEND) {
+                array_unshift($this->items, $input);
+            } else {
+                array_push($this->items, $input);
+            }
         }
 
         return $this;
     }
 
-    public function find(string $name, array $restrictToType=null, array $excludeType=null, &$type = null, &$index = null): ?AbstractInputType
+    public function find(string $name, array $restrictToType = null, array $excludeType = null, &$index = null): ?AbstractInputType
     {
-        foreach($this->items as $type => $items) {
-
+        foreach ($this->items as $index => $input) {
             // Check if we're restricting to or excluding specific types
-            if(null !== $restrictToType && !in_array($type, $restrictToType)) {
+            if (null !== $restrictToType && !in_array($input->getType(), $restrictToType)) {
                 continue;
-
-            } elseif(null !== $excludeType && in_array($type, $excludeType)) {
+            } elseif (null !== $excludeType && in_array($input->getType(), $excludeType)) {
                 continue;
             }
 
-            foreach($items as $index => $item) {
-                if($item->respondsTo($name)) {
-                    return $item;
-                }
+            if ($input->respondsTo($name)) {
+                return $input;
             }
+
         }
-        $type = null;
         $index = null;
         return null;
     }
 
-    public function getTypes(): array {
-        return array_keys($this->items);
+    public function getTypes(): array
+    {
+        $types = [];
+        foreach($this->items as $input) {
+            $types[] = $input->getType();
+        }
+        return array_unique($types);
     }
 
-    public function getItems(): array {
-        return $this->items;
+    public function getItems(): \Iterator
+    {
+        return (new \ArrayObject($this->items))->getIterator();
     }
 
-    public function getItemsByType(string $type): array {
-        return $this->items[$type] ?? [];
+    public function getItemsByType(string $type): \Iterator
+    {
+        return new InputTypeFilterIterator(
+            $this->getItems(),
+            [$type],
+            InputTypeFilterIterator::FILTER_INCLUDE
+        );
     }
 
-    public function getItemByIndex(string $type, int $index): ?AbstractInputType {
-        return $this->items[$type][$index] ?? null;
+    public function getItemsExcludeByType(string $type): \Iterator
+    {
+        return new InputTypeFilterIterator(
+            $this->getItems(),
+            [$type],
+            InputTypeFilterIterator::FILTER_EXCLUDE
+        );
+    }
+
+    public function getItemByIndex(int $index): ?AbstractInputType
+    {
+        return $this->items[$index] ?? null;
     }
 
     public static function merge(self ...$collections): self
     {
-        $items = [];
 
+        $iterator = new \AppendIterator;
         foreach ($collections as $c) {
-            foreach($c->items() as $type => $items) {
-                foreach($items as $item) {
-                    $items[] = $item;
-                }
-            }
+            $iterator->append($c->getItems());
         }
 
         $mergedCollection = new self();
-
-        foreach ($items as $input) {
-            try {
-                $mergedCollection->append($input, true);
-            } catch (\Exception $ex) {
-                // Already exists, so skip it.
-            }
+        foreach ($iterator as $input) {
+            $mergedCollection->add($input, true);
         }
-
         return $mergedCollection;
     }
 }
diff --git a/src/Input/InputHandlerFactory.php b/src/Input/InputHandlerFactory.php
index a899812..2ae425c 100644
--- a/src/Input/InputHandlerFactory.php
+++ b/src/Input/InputHandlerFactory.php
@@ -9,32 +9,37 @@ use pointybeard\Helpers\Foundation\Factory;
 
 final class InputHandlerFactory extends Factory\AbstractFactory
 {
-    const FLAG_SKIP_VALIDATION = 0x0001;
-
-    public static function getTemplateNamespace(): string
+    public function getTemplateNamespace(): string
     {
         return __NAMESPACE__.'\\Handlers\\%s';
     }
 
-    public static function getExpectedClassType(): ?string
+    public function getExpectedClassType(): ?string
     {
         return __NAMESPACE__.'\\Interfaces\\InputHandlerInterface';
     }
 
-    public static function build(string $name, InputCollection $collection = null, int $flags = null): Interfaces\InputHandlerInterface
+    public static function build(string $name, ...$arguments): object
     {
+
+        // Since passing flags is optional, we can use array_pad
+        // to ensure there are always at least 2 elements in $arguments
+        [$collection, $flags] = array_pad($arguments, 2, null);
+
+        $factory = new self;
+
         try {
-            $handler = self::instanciate(
-                self::generateTargetClassName($name)
+            $handler = $factory->instanciate(
+                $factory->generateTargetClassName($name)
             );
         } catch (\Exception $ex) {
             throw new Exceptions\UnableToLoadInputHandlerException($name, 0, $ex);
         }
 
-        if ($collection instanceof InputCollection) {
+        if (null !== $collection) {
             $handler->bind(
                 $collection,
-                Flags\is_flag_set($flags, self::FLAG_SKIP_VALIDATION)
+                $flags
             );
         }
 
diff --git a/src/Input/InputTypeFactory.php b/src/Input/InputTypeFactory.php
index 6d942dc..82b1115 100644
--- a/src/Input/InputTypeFactory.php
+++ b/src/Input/InputTypeFactory.php
@@ -4,19 +4,16 @@ declare(strict_types=1);
 
 namespace pointybeard\Helpers\Cli\Input;
 
-use pointybeard\Helpers\Functions\Flags;
 use pointybeard\Helpers\Foundation\Factory;
 
 final class InputTypeFactory extends Factory\AbstractFactory
 {
-    use Factory\Traits\hasSimpleFactoryBuildMethodTrait;
-    
-    public static function getTemplateNamespace(): string
+    public function getTemplateNamespace(): string
     {
         return __NAMESPACE__.'\\Types\\%s';
     }
 
-    public static function getExpectedClassType(): ?string
+    public function getExpectedClassType(): ?string
     {
         return __NAMESPACE__.'\\Interfaces\\InputTypeInterface';
     }
diff --git a/src/Input/InputTypeFilterIterator.php b/src/Input/InputTypeFilterIterator.php
new file mode 100644
index 0000000..e46e231
--- /dev/null
+++ b/src/Input/InputTypeFilterIterator.php
@@ -0,0 +1,39 @@
+<?php
+
+declare(strict_types=1);
+
+namespace pointybeard\Helpers\Cli\Input;
+
+class InputTypeFilterIterator extends \FilterIterator {
+
+    private $types;
+    private $mode;
+
+    public const FILTER_INCLUDE = 0x0001;
+    public const FILTER_EXCLUDE = 0x0002;
+
+    public function __construct(\Iterator $iterator, array $types=[], int $mode=self::FILTER_INCLUDE)
+    {
+        parent::__construct($iterator);
+
+        $this->types = array_map('strtolower', $types);
+        $this->mode = $mode;
+
+    }
+    public function accept()
+    {
+        $input = $this->getInnerIterator()->current();
+
+        switch($this->mode) {
+            case self::FILTER_EXCLUDE:
+                return !in_array($input->getType(), $this->types);
+                break;
+
+            case self::FILTER_INCLUDE:
+            default:
+                return in_array($input->getType(), $this->types);
+                break;
+
+        }
+    }
+}
diff --git a/src/Input/Interfaces/InputHandlerInterface.php b/src/Input/Interfaces/InputHandlerInterface.php
index 87a33ac..8345b30 100644
--- a/src/Input/Interfaces/InputHandlerInterface.php
+++ b/src/Input/Interfaces/InputHandlerInterface.php
@@ -8,9 +8,9 @@ use pointybeard\Helpers\Cli\Input;
 
 interface InputHandlerInterface
 {
-    public function bind(Input\InputCollection $inputCollection, bool $skipValidation = false): bool;
+    public function bind(Input\InputCollection $inputCollection, ?int $flags = null): bool;
 
-    public function validate(): void;
+    public function validate(?int $flags = null): void;
 
     public function find(string $name);
 
diff --git a/src/Input/Interfaces/InputTypeInterface.php b/src/Input/Interfaces/InputTypeInterface.php
index 92efb34..3a6bc13 100644
--- a/src/Input/Interfaces/InputTypeInterface.php
+++ b/src/Input/Interfaces/InputTypeInterface.php
@@ -16,7 +16,10 @@ interface InputTypeInterface
     const FLAG_TYPE_INCREMENTING = 0x0400;
 
     public function getType(): string;
+
     public function respondsTo(string $name): bool;
+
     public function __toString(): string;
+
     public function getDisplayName(): string;
 }
diff --git a/src/Input/Types/Argument.php b/src/Input/Types/Argument.php
index 21a9a5d..4550781 100644
--- a/src/Input/Types/Argument.php
+++ b/src/Input/Types/Argument.php
@@ -10,10 +10,9 @@ use pointybeard\Helpers\Functions\Cli;
 
 class Argument extends Input\AbstractInputType
 {
-
-    public function __construct(string $name = null, int $flags = null, string $description = null, object $validator = null, $default=null)
+    public function __construct(string $name = null, int $flags = null, string $description = null, object $validator = null, $default = null)
     {
-        if(null === $validator) {
+        if (null === $validator) {
             $validator = function (Input\AbstractInputType $input, Input\AbstractInputHandler $context) {
                 // This dummy validator is necessary otherwise the argument
                 // value is ALWAYS set to default (most often NULL) regardless
@@ -25,7 +24,8 @@ class Argument extends Input\AbstractInputType
         parent::__construct($name, $flags, $description, $validator, $default);
     }
 
-    public function getDisplayName(): string {
+    public function getDisplayName(): string
+    {
         return strtoupper($this->name());
     }
 
@@ -72,6 +72,6 @@ class Argument extends Input\AbstractInputType
             $second[$ii] = $secondaryLineLeadPadding.$second[$ii];
         }
 
-        return $first.implode($second, PHP_EOL);
+        return $first.implode(PHP_EOL, $second);
     }
 }
diff --git a/src/Input/Types/Flag.php b/src/Input/Types/Flag.php
index fba5f55..a3f2329 100644
--- a/src/Input/Types/Flag.php
+++ b/src/Input/Types/Flag.php
@@ -5,16 +5,13 @@ declare(strict_types=1);
 namespace pointybeard\Helpers\Cli\Input\Types;
 
 use pointybeard\Helpers\Functions\Flags;
-use pointybeard\Helpers\Functions\Strings;
-use pointybeard\Helpers\Functions\Cli;
-use pointybeard\Helpers\Cli\Input;
 
 class Flag extends Option
 {
     public function __construct(string $name = null, int $flags = null, string $description = null, object $validator = null, $default = false)
     {
-        if(Flags\is_flag_set($flags, self::FLAG_VALUE_REQUIRED) || Flags\is_flag_set($flags, self::FLAG_VALUE_OPTIONAL)) {
-            throw new \Exception("The flags FLAG_VALUE_REQUIRED and FLAG_VALUE_OPTIONAL cannot be used on an input of type Flag");
+        if (Flags\is_flag_set($flags, self::FLAG_VALUE_REQUIRED) || Flags\is_flag_set($flags, self::FLAG_VALUE_OPTIONAL)) {
+            throw new \Exception('The flags FLAG_VALUE_REQUIRED and FLAG_VALUE_OPTIONAL cannot be used on an input of type Flag');
         }
         parent::__construct($name, null, $flags, $description, $validator, $default);
     }
diff --git a/src/Input/Types/IncrementingFlag.php b/src/Input/Types/IncrementingFlag.php
index 33df708..8d850a1 100644
--- a/src/Input/Types/IncrementingFlag.php
+++ b/src/Input/Types/IncrementingFlag.php
@@ -5,15 +5,12 @@ declare(strict_types=1);
 namespace pointybeard\Helpers\Cli\Input\Types;
 
 use pointybeard\Helpers\Functions\Flags;
-use pointybeard\Helpers\Functions\Strings;
-use pointybeard\Helpers\Functions\Cli;
-use pointybeard\Helpers\Cli\Input;
 
 class IncrementingFlag extends Flag
 {
     public function __construct(string $name = null, int $flags = null, string $description = null, object $validator = null, $default = 0)
     {
-        if(Flags\is_flag_set($flags, self::FLAG_TYPE_INCREMENTING)) {
+        if (Flags\is_flag_set($flags, self::FLAG_TYPE_INCREMENTING)) {
             $flags = $flags | self::FLAG_TYPE_INCREMENTING;
         }
         parent::__construct($name, null, $flags, $description, $validator, $default);
diff --git a/src/Input/Types/LongOption.php b/src/Input/Types/LongOption.php
index 7d9af5b..17d73de 100644
--- a/src/Input/Types/LongOption.php
+++ b/src/Input/Types/LongOption.php
@@ -21,18 +21,18 @@ class LongOption extends Input\AbstractInputType
 
     public function respondsTo(string $name): bool
     {
-        return ($name == $this->name || $name == $this->short);
+        return $name == $this->name || $name == $this->short;
     }
 
-    public function getDisplayName(): string {
-
+    public function getDisplayName(): string
+    {
         $short =
             null !== $this->short()
             ? '-'.$this->short().', '
             : null
         ;
 
-        return sprintf("%s--%s", $short, $this->name());
+        return sprintf('%s--%s', $short, $this->name());
     }
 
     public function __toString(): string
@@ -84,6 +84,6 @@ class LongOption extends Input\AbstractInputType
             $second[$ii] = $secondaryLineLeadPadding.$second[$ii];
         }
 
-        return $first.implode($second, PHP_EOL);
+        return $first.implode(PHP_EOL, $second);
     }
 }
diff --git a/src/Input/Types/Option.php b/src/Input/Types/Option.php
index 2a193e3..ab081ab 100644
--- a/src/Input/Types/Option.php
+++ b/src/Input/Types/Option.php
@@ -4,14 +4,14 @@ declare(strict_types=1);
 
 namespace pointybeard\Helpers\Cli\Input\Types;
 
-use pointybeard\Helpers\Functions\Flags;
 use pointybeard\Helpers\Functions\Strings;
 use pointybeard\Helpers\Functions\Cli;
 use pointybeard\Helpers\Cli\Input;
 
 class Option extends Input\AbstractInputType
 {
-    public function getDisplayName(): string {
+    public function getDisplayName(): string
+    {
         return '-'.$this->name();
     }