# Do notation and matcher combined for call method not working

**URL:** <https://discourse.dry-rb.org/t/do-notation-and-matcher-combined-for-call-method-not-working/1736>\
**Category:** Support\
**Created:** [October 17, 2023, 7:24am UTC](https://discourse.dry-rb.org/t/do-notation-and-matcher-combined-for-call-method-not-working/1736 "2023-10-17T07:24:41Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![pdany1116](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.dry-rb.org/pdany1116/32/920_2.png) [@pdany1116](https://discourse.dry-rb.org/u/pdany1116)\
**Post date:** [October 17, 2023, 7:24am UTC](https://discourse.dry-rb.org/t/do-notation-and-matcher-combined-for-call-method-not-working/1736/1 "2023-10-17T07:24:41Z")

</div>

Hi there,

Dry-rb libraries beginner here, I was trying to do this:

```auto
class Create
  include Dry::Transaction::Operation
  include Dry::Monads::Do.for(:call)

  def call(params)
    result = yield some_other_call(params)

    # some logic with result
  end
end

```

But I got `no block given (yield)` error when running the tests.

This discussion [LocalJumpError: no block given (yield) in github actions](https://discourse.dry-rb.org/t/localjumperror-no-block-given-yield-in-github-actions/1316) was a hint that it might not work to have do notation for the same :call method, because Dry::Transaction::Operation defines a Matcher for the same :call method with ` include Dry::Matcher.for(:call, with: Dry::Matcher::ResultMatcher)`.

I could not find an explanation for this. Why is not possible to use both?

Gems:

- dry-monads 1.3.5
- dry-transaction 0.13.2

Thanks!

---

<div class="post-metadata">

**Author:** ![alassek](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.dry-rb.org/alassek/32/314_2.png) [@alassek](https://discourse.dry-rb.org/u/alassek)\
**Post date:** [October 17, 2023, 7:36pm UTC](https://discourse.dry-rb.org/t/do-notation-and-matcher-combined-for-call-method-not-working/1736/2 "2023-10-17T19:36:14Z")

</div>

Welcome! My first question is: why are you combining dry-monads and dry-transaction?

[dry-transaction’s future is uncertain](https://github.com/dry-rb/dry-transaction/issues/127). It was deprecated, then un-deprecated, and hasn’t really seen any activity since.

Part of the reason for this is that [dry-monads](https://dry-rb.org/gems/dry-monads/1.6/do-notation/) + [dry-auto\_inject](https://dry-rb.org/gems/dry-auto_inject/1.0/) basically provide all the things you get with dry-transaction with far greater flexibility.

If there are legacy reasons why you need dry-transaction, it will probably receive at least maintenance releases for the time being, but if you are starting fresh I would recommend just using do-notation.

That said, here’s the most basic approach to a do-notation Operation:

```ruby
#!/usr/bin/env ruby
# frozen_string_literal: true

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'
  gem 'dry-monads'
end

require 'dry/monads'

M = Dry::Monads

class Create
  include Dry::Monads[:result]
  include Dry::Monads::Do.for(:call)

  def call(params)
    result = yield some_other_call(params)

    Success(result)
  end

  private

  def some_other_call(params) = Success(params)
end

create = Create.new

case create.({ foo: "Bar" })
in M::Success(attributes)
  puts attributes.inspect
in M::Failure(err)
  raise err
end

```

---

<div class="post-metadata">

**Author:** ![pdany1116](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.dry-rb.org/pdany1116/32/920_2.png) [@pdany1116](https://discourse.dry-rb.org/u/pdany1116)\
**Post date:** [October 17, 2023, 8:17pm UTC](https://discourse.dry-rb.org/t/do-notation-and-matcher-combined-for-call-method-not-working/1736/3 "2023-10-17T20:17:47Z")

</div>

Hi, thanks for your time!

I consider the Create class an operation since I am including Dry::Transaction::Operation, which is later used in a transaction as a step.

The application we have, I would not necessarily say it is legacy. We have top-level business logic in dry-transactions, which are constructed from other transactions and operations.

I was surprised that I could not use the do notation in the same :call method and couldn’t find an explanation anywhere. I really like how transactions look and read, it’s way more natural than having do notation.

I ended up having something like this:

```auto
module Api
  class Operation
    def self.inherited(subclass)
      super
      subclass.include Dry::Transaction::Operation
    end
  end
end

class Create < Api::Operation
  include Dry::Monads::Do.for(:create)

  def call(params)
    create(params)
  end

  private

  def create(params)
    result = yield some_other_call(params)

    # some logic with result that returns Success/Failure
  end
end

```

Moved do notation for the private :create method.