Meld

Simple merge backend for text with a common ancestor.

This gem aims to provide a decoupled implementation of just the merging of versions. The assumption is that the versions have a common root.

It takes three instances of textblocks, BASE, THIS and OTHER and returns a hash of conflicts or a merged result.

Examples

Lets look at some examples

Nothing changed

Given three texts, all identical in content, returns the base's content

base = this = other = %Q{
  Lorem ipsum
}

Meld.new( base: base, this: this, other: other)

# -> { result: "Lorem ipsum" }

THIS or OTHER added to

Given three texts, where THIS or OTHER has additional content over the other two, return the text with additional content

base = other = %Q{
  Lorem ipsum
}

this_added = other + " dolor sit amet"

Meld.new( base: base, this: this_added, other: other)

# -> { result: "Lorem ipsum dolor sit amet" }

THIS and OTHER added to

Given three texts, where THIS and OTHER has additional content over base, return a new text with the additional content merged

base = %Q[
  .red {
    color: #f00;
  }
]

this = %Q[
  .red {
    color: #f00;
  }

  .blue {
    color: #00f;
  }
]

this = %Q[
  .red {
    color: #f00;
  }

  .green {
    color: #0f0;
  }
]

Meld.new( base: base, this: this, other: other)

# -> { result: ".red {\n  color: #f00;\n}\n\n.blue {\n  color: #00f;\n}\n\n.green {\n  color: #0f0;\n}" }

Conflicting changes

Given three text, where THIS and OTHER has both changed base in different ways, return a hash of all the conflicts and an empty result

base = %Q[
  .red {
    color: #f00;
  }
]

this = %Q[
  .red {
    color: #00f;
  }
]

this = %Q[
  .red {
    color: #0f0;
  }
]

Meld.new( base: base, this: this, other: other)

# -> { conflict: {this: {start: [2,10], end: [2,13]}, other: {start: [2,10], end: [2,12]}}, result: "" }

Installation

Add this line to your application's Gemfile:

gem 'meld'

And then execute:

$ bundle

Or install it yourself as:

$ gem install meld

Usage

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request