some

Inspired by Option.map in Scala.

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

/\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:

   dependencies:
     some:
       github: tkshnwesper/some
   

2. Run shards install

Usage

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.

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 (https://github.com/tkshnwesper/some/fork)
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 - creator and maintainer