It is much easier to track what is going on within the activity. Instead of transporting additional state via ctx, you expose the outcome via an additional end event.

This is my absolute favorite feature ever and the official reason for (re-)writing Trailblazer 2.1. It makes me happy every time I use it.

So why the over-complication? What we got now is replicating a chain of && in the former version. This time, however, you will know which condition failed and what went in by using tracing. Look at the trace above - it’s impossible to not understand what was going on.

Hey, that’s is an imaginary complication of our example - please don’t do this with every condition you have in your app.

.The firstparadigm centres on institutional power: ‘Our schools, our government, our businessesand corporations are permeated with the view that neither individual nor group aretrustworthy. There must be power over, power to control. This hierarchal system isinherent in our whole culture’. The second paradigm takes the opposite view: ‘Givena suitable climate, humankind is trustworthy, creative, self-motivated, powerful andconstructive – capable of releasing undreamed-of-potentialities’

importedfrom the business and commercial world.

target driven climate which has the potential to undermine theimportance of ‘relationship

patch: -> { step Destroy.method(:tidy_storage), before: :delete_model }

URI::MailTo::EMAIL_REGEXP

Since we're not passing any inputs to ListAccounts, it makes sense to use .run! instead of .run. If it failed, that would mean we probably messed up writing the interaction.

ActiveModel provides a powerful framework for defining callbacks. ActiveInteraction hooks into that framework to allow hooking into various parts of an interaction's lifecycle.

It requires an account to update, but the other inputs are optional. If they're missing, it'll ignore those attributes. If they're present, it'll update them.

If ActiveModel deals with your nouns, then ActiveInteraction handles your verbs.

For this one we'll define a helper method to handle raising the correct errors. We have to do this because calling .run! would raise an ActiveInteraction::InvalidInteractionError instead of an ActiveRecord::RecordNotFound. That means Rails would render a 500 instead of a 404.

For branching out a separate path in an activity, use the Path() macro. It’s a convenient, simple way to declare alternative routes

step :decide_type, Output(Activity::Left, :credit_card) => Track(:with_credit_card)

# Create the track, which would automatically create an implicit End with the same id.
Track(:with_credit_card) do
    step :authorize
    step :charge
end

class Example::ValidationErrorTrack < Trailblazer::Activity::Railway
  step :validate_model, Output(:failure) => Track(:validation_error)
  step :save,           Output(:failure) => Track(:validation_error)

  # Can't use fail here or the magnetic_to won't work and  Track(:validation_error) won't work
  step :log_validation_error, magnetic_to: :validation_error,
    Output(:success) => End(:validation_error), 
    Output(:failure) => End(:validation_error) 
end

puts Trailblazer::Developer.render o
Reloading...

#<Start/:default>
 {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
#<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
 {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
 {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
#<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
 {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
 {Trailblazer::Activity::Right} => #<End/:success>
#<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
 {Trailblazer::Activity::Left} => #<End/:validation_error>
 {Trailblazer::Activity::Right} => #<End/:validation_error>
#<End/:success>

#<End/:validation_error>

#<End/:failure>

class Example::ValidationErrorTrack::VPathHelper1 < Trailblazer::Activity::Railway
   validation_error_path = Path(end_id: "End.validation_error", end_task: End(:validation_error)) do
    step :log_validation_error
  end
  step :validate_model, Output(:failure) => validation_error_path
  step :save,           Output(:failure) => validation_error_path
end

o=Example::ValidationErrorTrack::VPathHelper1; puts Trailblazer::Developer.render o
Reloading...

#<Start/:default>
 {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
#<Trailblazer::Activity::TaskBuilder::Task user_proc=validate_model>
 {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
 {Trailblazer::Activity::Right} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
#<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
 {Trailblazer::Activity::Right} => #<End/:validation_error>
#<Trailblazer::Activity::TaskBuilder::Task user_proc=save>
 {Trailblazer::Activity::Left} => #<Trailblazer::Activity::TaskBuilder::Task user_proc=log_validation_error>
 {Trailblazer::Activity::Right} => #<End/:success>
#<End/:success>

#<End/:validation_error>

#<End/:failure>

Subprocess will try to match the nested ends’ semantics to the tracks it knows. You may wire custom ends using Output.

step :direct_debit

Patching has no implicit, magical side-effects and is strongly encouraged to customize flows for a specific case in a quick and consise way.

However, it can be a PITA if you want to customize one of those deeply nested components and add or remove a certain step, for example.

While you could nest an activity into another manually, the Subprocess macro will come in handy.

The macro automatically wires all of Validate’s ends to the known counter-part tracks.

Since notify sits on the “failure” track and hence is “magnetic to” :failure, find_provider will be connected to it.

This connects the failure output to the previous task, which might create an infinity loop and waste your computing time - it is solely here for demonstrational purposes.

how to track on-call coverage

Personally, I'm starting to think that the feature where it automatically adds xray.js to the document is more trouble than it's worth. I propose that we remove that automatic feature and just make it part of the install instructions that you need to add this line to your template/layout: <%= javascript_include_tag 'xray', nonce: true if Rails.env.development? %>

Now that I've thought more about it, I honestly think the auto-adding the script feature is overrated, over-complicated, and error-prone (#98, #100), and I propose we just remove it (#110).

now that I've thought more about it, I think the auto-adding the script feature is overrated, over-complicated, and error-prone (#100), and ought to just be removed (#110).

now that I realize how easy it is to just manually include this in my app: <%= javascript_include_tag 'xray', nonce: true if Rails.env.development? %> I regret even wasting my time getting it to automatically look for and add a nonce to the auto-injected xray.js script

Sass variables, like all Sass identifiers, treat hyphens and underscores as identical. This means that $font-size and $font_size both refer to the same variable. This is a historical holdover from the very early days of Sass, when it only allowed underscores in identifier names. Once Sass added support for hyphens to match CSS’s syntax, the two were made equivalent to make migration easier.

As a workaround, I guess I'll have to disable my strict CSP in development, but I'd prefer to keep it strict in development as well so that I ran into any CSP issues sooner...

Keeping bootstrap-sass in sync with upstream changes from Bootstrap used to be an error prone and time consuming manual process. With Bootstrap 3 we have introduced a converter that automates this.

It's recommended to configure this library by setting environment variables.

Keep in mind that third party code with references to other files also processed by the asset Pipeline (images, stylesheets, etc.), will need to be rewritten to use helpers like asset_path.

Here's the last issue where source maps were discussed before the beta release.

How do you know if source maps are working correctly? Try adding a syntax error to one of your assets and use the console to debug. Does it show the correct file and source location? Or does it reference the top level application.js file?

Your Rails app Gemfile may have a line requiring sass-rails 5.0: gem 'sass-rails', '~> 5.0' # or gem 'sass-rails', '~> 5' These will prevent upgrade to sprockets 4, if you'd like to upgrade to sprockets 4 change to: gem 'sass-rails', '>= 5'

That’s it. If you have a previous “precompile” array, in your app config, it will continue to work. For continuity sake I recommend moving over those declarations to your manifest.js file so that it will be consistent.

That’s pretty gnarly. While the name of the constant LOOSE_APP_ASSETS gives me some idea of what it does, it still takes a second to wrap your mind around. If you were trying to figure out what assets are being precompiled and you did a puts config.assets.precompile that lambda object would be utterly baffling.

Yes, we could and should use Reform or Dry-validation here.

provide interfaces so you don’t have to think about them

found that using only the Pascal-provided control structures, the correct solution was given by only 20% of the subjects, while no subject wrote incorrect code for this problem if allowed to write a return from the middle of a loop.

computers theoretically need only one machine instruction (subtract one number from another and branch if the result is negative)

Now you can easily spot them! The rule is: if you see a Result it means that this function can throw an exception. And you even know its type in advance.

we also wrap them in Failure to solve the second problem: spotting potential exceptions is hard

Not all cases can be covered and easily restored. And sometimes when we will reuse this function for different use-cases we will find out that it requires different restore logic.

But why do we return 0? Why not 1? Why not None? And while None in most cases is as bad (or even worse) than the exceptions, turns out we should heavily rely on business logic and use-cases of this function.

Almost everything in python can fail with different types of exceptions: division, function calls, int, str, generators, iterables in for loops, attribute access, key access, even raise something() itself may fail. I am not even covering IO operations here. And checked exceptions won’t be supported in the nearest future.

You still need to have a solid experience to spot these potential problems in a perfectly readable and typed code.

print will never be actually executed. Because 1 / 0 is an impossible operation and ZeroDivisionError will be raised.

So, the sad conclusion is: all problems must be resolved individually depending on a specific usage context. There’s no silver bullet to resolve all ZeroDivisionErrors once and for all. And again, I am not even covering complex IO flows with retry policies and expotential timeouts.

despite initially appearing to be an appropriate and effective response to a problem, has more bad consequences than good ones

I'm not a fan of listing exceptions functions can throw, especially here in Python, where it's easier to ask forgiveness than permission.

certainly I wouldn't want it to start telling me that I'm not catching these!

Enforces better architecture

The author will offer presentation/game sessions on Tabletopia, in French and English. In addition, the game will be freely available for players on Tabletopia as soon as the written rules are available.

This tedium would be unacceptable in an action game, but Windbound is a survival game. In survival games, death is supposed to mean something. Loss of progress represents the stakes; repetition is the barrier of entry.

Do notation provides an alternative to bind, which also flattens the code.

However, you don’t need to have an extensive knowledge of monads to use ROP in your code.

For historical reasons, this map is instead called fmap in Haskell.

In other words, once you've used Maybe you cannot hit nil with a missing method. This is remarkable because even &. doesn't save you from omitting || "No state" at the end of the computation. Basically, that's what they call "Type Safety".

It's hard to say why people think so because you certainly don't need to know category theory for using them, just like you don't need it for, say, using functions.

As you can see, we end up with a lot of boilerplate if-statements. The code is more verbose. And it’s difficult to follow the main logic.

Don’t worry if you get confused at first. Everyone does. I’ve listed some other references at the end that may help. But don’t give up.

So if you don't yet understand functors or applicative functors, check out part 1 and part 2 of this series!

This is a useful approach to error handling, but please don’t take it to extremes! See my post on “Against Railway-Oriented Programming”.

Feel free to pick and choose what you need for your applications.

Software architecture is about making fundamental structural choices that are costly to change once implemented.

They do not maintain a to-do list (mentally or physically).

If you ask my former students, they will tell you that as a teacher, my goal is to do nothing. I dream of the day when I can sit at my desk, feet propped up, reading a book, while the classroom bursts with activity and learning around me.

In the short term you may have the stamina to get up earlier, stay later, and out-work the demands you face. But the inverse equation of shrinking resources and increasing demands will eventually catch up to you, and at that point how you involve others sets the ceiling of your leadership impact.

The legendary cfp-app will become a Rails-to-TRB refactoring tutorial.

And yes, at TRB GmbH, we do pay people to work on OSS

The new 2.1 version comes with a few necessary but reasonable changes in method signatures. As painful as that might sound to your Rails-spoiled ears, we preferred to fix design mistakes now before dragging them on forever.

The new call API is much more consistent and takes away another thing we kept explaining to new users - an indicator for a flawed API.

It’s so simple that I sometimes wonder why it took years to develop it!

note that TRB source code modifications are not proprietary

The bare bones operation without any Trailblazery is implemented in the trailblazer-operation gem and can be used without our stack.

While Trailblazer offers you abstraction layers for all aspects of Ruby On Rails, it does not missionize you. Wherever you want, you may fall back to the "Rails Way" with fat models, monolithic controllers, global helpers, etc. This is not a bad thing, but allows you to step-wise introduce Trailblazer's encapsulation in your app without having to rewrite it.

Only use what you like.

you can pick which layers you want. Trailblazer doesn't impose technical implementations

# catch multi-char special key sequences read -sN1 -t 0.0001 k1 read -sN1 -t 0.0001 k2 read -sN1 -t 0.0001 k3 key+=${k1}${k2}${k3}

Beware, though: What you are about to see is not particularly elegant. In fact, the TTY subsystem — while quite functional from a user's point of view — is a twisty little mess of special cases. To understand how this came to be, we have to go back in time.

However, banning him opens a very dangerous precedent, making the US more like a dictatorship... more like China. Also it's not effective. Those who were silenced will only have more motivation, and the risk of terrorism is greatly increased. The people must decide what is true. Not big companies. Individuals must be able to express their beliefs. Bot accounts must be banned, but real individuals must not. If you think a group of people is a bunch of idiots who believe fake news, then, tough, that's democracy for you. Maybe it means that your government is not investing enough in education and welfare to properly educate and give hope to those people.

I oppose the banning of Donald Trump and his non-violent believers/content from social media platforms such as Facebook Twitter, YouTube and Amazon. I feel (irrationally?) Trump is arrogant and disgusting as a person. I like some of his anti-CCP policies, but not sure I'd vote for him. The "USA First" stance is particularly damaging as it scares USA allies away. I don't think there's enough evidence for the electoral fraud allegations, but I haven't researched the court cases extensively. However, banning him opens a very dangerous precedent, making the US more like a dictatorship... more like China. Also it's not effective. Those who were silenced will only have more motivation, and the risk of terrorism is greatly increased. The people must decide what is true. Not big companies. Individuals must be able to express their beliefs. Bot accounts must be banned, but real individuals must not. If you think a group of people is a bunch of idiots who believe fake news, then, tough, that's democracy for you. Maybe it means that your government is not investing enough in education and welfare to properly educate and give hope to those people. I'm against violence.

AWS can even terminate or suspend its agreement with a customer immediately under certain circumstances as it did in 2010 with Wikileaks, pointing to violations of AWS’ terms of service.

The swiftness with which Amazon acted shouldn’t come as a shock. Companies have been disclosing details about their deals with Amazon that warn of these kinds of sudden discontinuations for years.

The incident demonstrates a type of power that Amazon wields almost uniquely because so many companies rely on it to deliver computing and data storage.

i dont know why everyone wants to **** on everything that is not a "AAA" game, its not in its perfect state, but far from deserve a 3, i will give it a 9 so it counters the "just hate

Personal todo lists don’t depend on others using the same system (no network effects)

{a: 1, b: 2, c: 3, d: 4} => {a:, b:, **rest} # a == 1, b == 2, rest == {:c=>3, :d=>4}

{a, b, ...rest} = {a: 1, b: 2, c: 3, d: 4}

Nevermind, I use now reform-rails

@adisos if reform-rails will not match, I suggest to use: https://github.com/orgsync/active_interaction I've switched to it after reform-rails as it was not fully detached from the activerecord, code is a bit hacky and complex to modify, and in overall reform not so flexible as active_interaction. It has multiple params as well: https://github.com/orgsync/active_interaction/blob/master/spec/active_interaction/modules/input_processor_spec.rb#L41

Any idea @AaronLasseigne if this is mergeable?

This is a breaking change so it'll have to go into a major release. I was working on a v4 release but it's too much. I think I'm going to pair it back and we can add this to the new v4. When I have that ready, I'll rebase the merge onto that branch.

No one has requested it before so it's certainly not something we're planning to add.

To give a little more context, structures like this often come up in my work when dealing with NoSQL datastores, especially ones that rely heavily on JSON, like Firebase, where a records unique ID isn't part of the record itself, just a key that points to it. I think most Ruby/Rails projects tend towards use cases where these sort of datastores aren't appropriate/necessary, so it makes sense that this wouldn't come up as quickly as other structures.

Thanks, I'll continue leaning on the array workaround for my use case then.

I don't think seeing it in Rails PRs naturally means we should do it blankly. Put it another way, what's the justification in those PRs for doing it?

The main realization came when I figured out that the main_model was just another association. This means we can move a lot of logic to just that class and reason about it a lot better.

So how are we going to create a model that doesn’t have a database table behind it? There are several potential solutions including various plugins but we’re going to use the method described in an entry on the Code Tunes blog. This shows a techinque that involves overriding a couple of methods in an ActiveRecord model and then manually defining the columns in the model file rather than in the database table. In our Recommendation model we’ll add in the two overridden methods and then use the column class method to define the columns in a similar way to how they’re defined in a migration file.

Examples of different ways of defining forms

Bureaucrat doesn't define save

The assert method is used by all the other assertions. It pushes the second parameter to the list of errors if the first parameter evaluates to false or nil.

For the usage in society, see Second-class citizen.

Set your models free from the accepts_nested_attributes_for helper. Action Form provides an object-oriented approach to represent your forms by building a form object, rather than relying on Active Record internals for doing this.

Take 3, Previously attempted in 2012 (#8189) and 2015 (#19709). This new version uses ActiveModel Attributes API.

We are still open to the idea but the implementation should leverage the attributes API introduced in Rails 5.2 in Active Model.

Fork rails, add github.com/georgebrock/rails as a remote, merge this branch into rails/4.0.2 (the tag), and then use your fork of Rails: gem 'rails', github: 'yourusername/rails'

If you take it to it's logical conclusion you'd only accept the correct types for boolean, integer, decimal, etc. columns, which is obviously crazy.

More often than not, the expression ‘taken to its logical conclusion’ serves to point up the absurdity of a piece of reasoning we come across.

I need a holiday to get over a holiday

I wish there were no Mondays

The golden standard I suppose is set by the rhyme: There is a hole in my bucket, dear Liza, dear Liza. Of course, fixing it requires the use of the bucket at some stage, and so the loop closes.

In object-oriented programming, information hiding (by way of nesting of types) reduces software development risk by shifting the code's dependency on an uncertain implementation (design decision) onto a well-defined interface. Clients of the interface perform operations purely through it so if the implementation changes, the clients do not have to change.

This article explains why you shouldn't use getters and setters (and when you can use them) and suggests a design methodology that will help you break out of the getter/setter mentality.