# NinjaDiffer

_NinjaDiffer was forked from [Differ](https://github.com/pvande/differ), by Pieter Vande Bruggen.
This gem shares logical and grammatical namespace with Differ. You will see the
names used interchangeably for a time. This is a full replacement for Differ,
running both gems together is not recommended._

> As streams of text swirled before the young man's eyes, his mind swam with thoughts of many things. They would have to wait, however, as he focussed his full concentration on the shifting patterns ahead of him. A glint of light reflecting off a piece of buried code caught his eye and any hope he had was lost. For the very moment he glanced aside, the landscape became Different.
> The young man gave a small sigh and trudged onward in solemn resignation, fated to wander the desolate codebanks in perpetuity.

NinjaDiffer is a flexible, pure-Ruby diff library, suitable for use in both command
line scripts and web applications.  The flexibility comes from the fact that
diffs can be built at completely arbitrary levels of granularity (some common
ones are built-in), and can be output in a variety of formats.

## Installation

Add this to your gemfile if you use bundler

```ruby
gem 'ninja-differ'
```

and bundle to install

```bash
bundle install
```

or install it manually

```bash
sudo gem install differ
```

## How do I use this thing?

There are a number of ways to use Differ, depending on your situation and needs. Lets examplify:

```ruby
require 'differ'

@original = "Epic lolcat fail!"
@current  = "Epic wolfman fail!"
```

There are a number of built-in diff_by_* methods to choose from for standard use:

```ruby
Differ.diff_by_line(@current, @original)
# => {"Epic lolcat fail!" >> "Epic wolfman fail!"}

Differ.diff_by_word(@current, @original)
# => Epic {"lolcat" >> "wolfman"} fail!

Differ.diff_by_char(@current, @original)
# => Epic {+"wo"}l{-"olcat "}f{+"m"}a{+"n fa"}il!
```

### Ok, but that doesn't quite cover my case, I have to split by "whatever".

No problem, you can call diff directly and supply your own boundary string:

```ruby
Differ.diff(@current, @original) # Implicitly by line by default
# => {"Epic lolcat fail!" >> "Epic wolfman fail!"}

Differ.diff(@current, @original, 'i')
# => Epi{"c lolcat fa" >> "c wolfman fa"}il
```

### Yeah, thats nice. But a simple string might not always cut it...

Well, you can supply a regex instead of your string if you have to:

```ruby
Differ.diff(@original, @current, /[a-z]i/)
# => E{"c wolfman f" >> "c lolcat f"}l!
```

Include a capture group if you want to keep the separator:

```ruby
Differ.diff(@original, @current, /([a-z]i)/)
# => Epi{"c wolfman f" >> "c lolcat f"}ail!
```

### Ok, ok, but I don't like having to write "Differ" everywhere.

If you would like something a little more inline you can `require 'differ/string'` to get some added inline string magic:

```ruby
@current.diff(@original) # Implicitly by line by default
# => {"Epic lolcat fail!" >> "Epic wolfman fail!"}
```

Or a lot more inline:

```ruby
@current - @original # Implicitly by line by default
# => {"Epic lolcat fail!" >> "Epic wolfman fail!"}

Differ.separator = ' ' # Custom string
@current - @original
# => Epic {"lolcat" >> "wolfman"} fail!

Differ.separator = /[a-z]i/ # Custom regex without capture group
@original - @current
# => E{"c wolfman f" >> "c lolcat f"}l!

Differ.separator = /([a-z]i)/ # Custom regex with capture group
@original - @current
# => Epi{"c wolfman f" >> "c lolcat f"}ail!
```

So we've pretty much got you covered.

## What about output formatting?

Need a different output format?  We've got a few of those too:

```ruby
Differ.format = :ascii  # Default
Differ.format = :color
Differ.format = :html
Differ.format = :patch

Differ.format = MyCustomFormatModule
```

The formatter must respond to the call method that takes an instant of the Change class as an argument and returns a string.

### But I don't want to change the system-wide default for only a single diff output!

Yeah, we either:

```ruby
diff = @current - @original
diff.format_as(:color)
```

Or with your own formatter:

```ruby
diff = @current - @original
diff.format_as(->(c){c.to_s})
```

> Know always right from wrong, and let others see your good works.