https://github.com/tkshnwesper/some

`unless var.nil?` as a block
https://github.com/tkshnwesper/some

functional-programming monad

Last synced: 8 days ago
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`unless var.nil?` as a block

• Host: GitHub
• URL: https://github.com/tkshnwesper/some
• Owner: tkshnwesper
• License: mit
• Created: 2022-04-05T09:58:10.000Z (almost 3 years ago)
• Default Branch: main
• Last Pushed: 2022-04-08T16:19:55.000Z (almost 3 years ago)
• Last Synced: 2024-11-09T02:38:49.037Z (2 months ago)
• Topics: functional-programming, monad
• Language: Crystal
• Homepage:
• Size: 7.81 KB
• Stars: 1
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# some

Inspired by `Option.map` in Scala.

`unless var.nil?`, but as a block. Might save a few lines ;)

```crystal

/\d+/.match("n1.txt").fmap do |match_data|  # => (MatchData | Nil)

  match_data[0].fmap do |level_str|         # => (String | Nil)

    level_str.to_i32                        # => 1

  end

end

```

## Installation

1. Add the dependency to your `shard.yml`:

   ```yaml

   dependencies:

     some:

       github: tkshnwesper/some

   ```

2. Run `shards install`

## Usage

```crystal

require "some"

possibly_nil : String | Nil

possibly_nil = "Hello"

Some.new(possibly_nil).fmap do |definitely_not_nil|

  puts "#{definitely_not_nil}! Greetings, young 'un!" # gets executed as expected!

end

possibly_nil = nil

Some.new(possibly_nil).fmap do

  `rm -rf /` # this won't get executed

end

```

### Object extension

You may also use the lib by enabling object extensions.

```crystal

some_object_extension(:some_map) # takes an optional parameter which sets method name (default: fmap)

result = 10.some_map do |value|

  value.to_s

end

puts result # => 10

```

Using `Some.new` would fail the compilation whenever the parameter passed cannot be `nil`. For example, `Some.new("hello")` would give compilation error.

However, the object extension can be used even on those objects which do not have `Nil` in their union type. For example `"hello".fmap` would not result in a compilation error.

## 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 a new Pull Request

## Contributors

- [tkshnwesper](https://github.com/tkshnwesper) - creator and maintainer