RubyLambdas

Expose Ruby object methods as lambdas (functions).

Installation

Add this line to your application's Gemfile:

gem 'ruby-lambdas', require: 'ruby/lambdas'

And then execute:

$ bundle

Or install it yourself as:

$ gem install ruby-lambdas

Usage

Basics:

require "ruby/lambdas"

Strings::Strip.call(" hello ") # => "hello"

# Strings::Trim is an alias to the Strings::Strip function
Strings::Trim.call(" hello ") # => "hello"

# Other ways to call a lambda (function):
Strings::Trim[" hello "]
Strings::Trim.(" hello ")    # Syntactic sugar to hide “call”.
Strings::Trim.===(" hello ") # This allows a proc object to be the target of a when clause in a case statement.
Strings::Trim.yield(" hello ")

Partial application (curried functions):

require "ruby/lambdas"

# We call a function with fewer arguments than it expects and It returns a
# function that takes the remaining arguments.
# And this is called Partial Application of Functions. e.g:

Strings::GSub.call(/[aeiou]/, "hello", "*")           # => "h*ll*"
Strings::GSub.call(/[aeiou]/).call("hello", "*")      # => "h*ll*"
Strings::GSub.call(/[aeiou]/).call("hello").call("*") # => "h*ll*"

# Last example with an alternative syntax:
Strings::GSub.(/[aeiou]/).("hello").("*") # => "h*ll*"

# ---

replace_vowels = Strings::GSub.call(/[aeiou]/)

replace_vowels.call("_", "banana") # => "b_n_n_"

# ---

hide_vowels = replace_vowels.call("*")

hide_vowels.call("hello") # => "h*ll*"

Pipelines:

require "ruby/lambdas"

###########################
# RUBY_VERSION >= '2.6.0' #
###########################

value = ' I WILL be a url slug   '

value
  .then(&Strings::Strip)
  .then(&Strings::Downcase)
  .then(&Strings::GSub[' ', '-'])

# => "i-will-be-a-url-slug"

###########################
# RUBY_VERSION >= '2.5.0' #
###########################

value = ' I WILL be a url slug   '

value
  .yield_self(&Strings::Strip)
  .yield_self(&Strings::Downcase)
  .yield_self(&Strings::GSub[' ', '-'])

# => "i-will-be-a-url-slug"

Composing functions (RUBY_VERSION >= '2.6.0'):

require "ruby/lambdas"
                                # -- Alternative syntax --
Slugify =                       # Slugify =
  Strings::FromObject           #   Strings::String
    .>> Strings::Strip          #     >> Strings::Trim      \
    .>> Strings::Downcase       #     >> Strings::LowerCase \
    .>> Strings::GSub[' ', '-'] #     >> Strings::ReplaceAll[' ', '-']

# Reading the previous composition (Step by step):
#   1. Convert a given object (first input) as a String
#   2. Remove all whitespaces from both sides of a string.
#   3. Convert a string to all lower case.
#   4. Replace all occurrences of " " by "-".

#########
# Usage #
#########
Slugify.(nil)                        # => ""
Slugify.(1)                          # => "1"
Slugify.(1.0)                        # => "1.0"
Slugify.(' I WILL be a url slug   ') # => "i-will-be-a-url-slug"

Strict mode

By default, all functions believe in their given inputs data types. To change this behavior, you can enable the strict mode (data type checking) via require "ruby/lambdas/strict-mode". e.g:

p ["2", "4"].map(&Numerics + "1") # => ["12", "14"]

require "ruby/lambdas/strict-mode"

p ["2", "4"].map(&Numerics + "1") # => Numerics::TypeError ("1" must be Numeric)
p ["2", "4"].map(&Numerics + 1)   # => Numerics::TypeError ("2" must be Numeric)
p [2, "4"].map(&Numerics + 1)     # => Numerics::TypeError ("4" must be Numeric)
p [2, 4].map(&Numerics + 1)       # => [3, 5]

Do you like it?

So, look in examples folder to see more ideas and benchmarks.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/serradura/ruby-lambdas. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the RubyLambdas project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.