you can use the wtf? command to display a few lines of the backtrace for the most recent exception

The absence of a method name here is per design: this object does only one thing, and hence what it does is reflected in the class name.

There’s no additional logic from Trailblazer happening here. The function returns a well-defined hash which is passed as an argument to step.

It will return the result as a Dry::Monads::Result object which can be either successful or failure.

# Yes, you can use lambdas as steps, too! step ->(ctx, params:, **) { params.is_a?(Hash) }

Keyword arguments allow to define particular parameters as required. Should the parameter be missing, they also provide a way to set a default value. This is all done with pure Ruby.

(match = html.match(/<meta name="csp-nonce" content="([^"]*)"/)) && match[1] html[/<meta name="csp-nonce" content="([^"]*)"/, 1]

Please note that the actual task doesn’t have to be a proc! Use a class, constant, object, as long as it exposes a #call method it will flow.

You may use keyword arguments in your filters for type safety and better readable code.

a task in an activity can be any callable Ruby object

Your actual logic happens in tasks, the labeled boxes. A task may be any callable Ruby object, an instance method or even another activity.

Trailblazer is an architectural pattern that comes with Ruby libraries to implement that pattern.

include Dry::Monads::Do.for(:call)

bind applies unwrapped Success value to the block, which should return a Result object. No-op on Failure

Operations define the flow of their logic using the DSL and implement the particular steps with pure Ruby.

Yes, Trailblazer is adding new abstractions and concepts and they are different to the 90s-Ruby, but now, at the latest, it becomes obvious how this improves the developing process. We’re no longer talking in two-dimensional method stack traces or byebug hoops, the language and conception is changing to the actual higher level code flow, to activities sitting in activities structured into smaller step units.

There are times where it is useful to know whether a value was passed to run or the result of a filter default. In particular, it is useful when nil is an acceptable value.

main > h = {key_with_nil_value: nil}
=> {:key_with_nil_value=>nil}

main > h[:key_with_nil_value]
=> nil

main > h[:missing_key]  # this would be undefined in JavaScript (a useful distinction) rather than null, but in Ruby it's indistinguishable from the case where a nil value was actually explicitly _supplied_ by the caller/user
=> nil

# so we have to check for "missingness" ("undefinedness"?) differently in Ruby

main > h.key?(:key_with_nil_value)
=> true

main > h.key?(:missing_key)
=> false

The problem is that you what you want is actually not de-structuring at all. You’re trying to go from 'arg1', { hash2: 'bar', hash3: 'baz' }, { hash1: 'foo' } (remember that 'arg1', foo: 'bar' is just shorthand for 'arg1', { foo: 'bar' }) to 'arg1', { hash1: 'foo', hash2: 'bar', hash3: 'baz' } which is, by definition, merging (note how the surrounding structure—the hash—is still there). Whereas de-structuring goes from 'arg1', [1, 2, 3] to 'arg1', 1, 2, 3

{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}

You can rescue at the method level, but more likely you’d want to rescue at the statement level.

(Yay for the hashrocket resurgence!)

we’re going to look how improved pattern matching and rightward assignment make it possible to “destructure” hashes and arrays in Ruby 3—much like how you’d accomplish it in, say, JavaScript

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

you can do pairs.each_with_object({}) do |(multiparameter_name, value), attributes|

values_with_empty_parameters.each_value.all?(&:nil?) This comment has been minimized. Show comment Hide comment Copy link Quote reply egilburg on Apr 9, 2015 Contributor you can do values_with_empty_parameters.values.none? [nil, nil].none? => true Pick your reaction egilburg on Apr 9, 2015 Contributor you can do values_with_empty_parameters.values.none? [nil, nil].none? => true

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.

Some languages like Smalltalk and Ruby only allow access via object methods

DSLs can be problematic for the user since the user has to manage state (e.g. am I supposed to call valid? first or update_attributes?). This is exactly why the #validate is the only method to change state in Reform.

I like your API here much better than reform's API.

reform conflates these two responsibilities into a single validate method

Compared to existing Ruby desktop frameworks, such as Shoes, Bowline's strengths are its adherence to MVC and use of HTML/JavaScript.

Set your models free from the accepts_nested_attributes_for helper. Active 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.

This allows you to execute multiple scripts in parallel.

GIL free JavaScript execution The Ruby Global interpreter lock is released when scripts are executing

Premailer is written in Ruby

Terminal Apps The Easy Way

json.(

You can use the match method with the :via option to match multiple verbs at once:

Dart Sass has replaced Ruby Sass as the canonical implementation of the Sass language.

optcarrot, is a headless NES emulator that the Ruby core team are using as a CPU-intensive optimization target.

StackProf.start(mode: :cpu) StackProf.stop StackProf.results('/tmp/some.file')

However, if perform was creating threads and you ended up with closures inside perform, then you could end up with several threads referencing the same local variables captured through the closures. So you do have to be careful about scope issues when you create threads but you don't have to worry about it when dealing with simple methods that only work with local variables

The local variables, such as your hash, are local to the particular invocation of the surrounding method. If two threads end up calling perform at the same time, then each call will get its own execution context and those won't overlap unless there are shared resources involved: instance variables (@hash), class variables (@@hash), globals ($hash), ... can cause concurrency problems. There's nothing to worry about thread-wise with something simple like your perform.

Ruby is the programming language used in Translation Proxy. For Sarah, Object Oriented Design “done the Ruby way” is so enjoyable and is the part of her work that she likes most.

Ruby has some really nice libraries for working with linked data. These libraries allow you to work with the data in both a graph and resource-oriented fashion, allowing a developer to use the techniques that best suit his or her use cases and skills.

Time.current returns said timestamp, and Time.now its equivalent in the system time zone.

Since Ruby 1.9.2, Time implementation uses a signed 63 bit integer, Bignum or Rational. The integer is a number of nanoseconds since the Epoch which can represent 1823-11-12 to 2116-02-20. When Bignum or Rational is used (before 1823, after 2116, under nanosecond), Time works slower as when integer is used.

There is a usability problem here, it's basically impossible to read the output of Time#inspect in such a case, even though the input was readable.

So, which is better? t.inspect # => "2007-11-01 15:25:00 8483885939586761/68719476736000000 UTC" t.inspect # => "2007-11-01 15:25:00.123456789000000004307366907596588134765625 UTC"

Introducing Module#const_source_locationUsing Method#source_location made finding the location of any method fairly easy. Unfortunately, there wasn’t an equivalent for constants. This meant that unless the constant you needed to find was defined in your codebase, finding its source location was not easy.

To stop emitting the warnings, just add RUBYOPT=-W:no-deprecated.

Enumerable#tally is added. It counts the occurrence of each element. ["a", "b", "c", "b"].tally #=> {"a"=>1, "b"=>2, "c"=>1}

Enumerator::Lazy#eager is added. It generates a non-lazy enumerator from a lazy enumerator.

A beginless range is experimentally introduced. It might not be as useful as an endless range, but would be good for DSL purposes.

It does change it, but it makes it much simpler in my opinion. It is basically "the receiver is statically the explicit literal special variable self or implicit." This gets rid of the current exception for private writer methods (self.foo = bar).

I guess much like Range literals in general, it's often needed to have parens around them.

Why don't you allow a range without end, like (1..)? There are two advantages. First, we can write ary[1..] instead of ary[1..-1]. The -1 is one of the most I dislike in Ruby. It is very magical, ugly, redundant, and disappointing. I envy Python's ary[1:]. I know that ary.drop(1) is slightly fast, but too long for such a common operation, IMO. Second, we can write (1..).each {|n| ... }.

require 'set' class Array def uniq_elements(&prc) prc ||= ->(e) { e } uniques, dups = {}, Set.new each do |e| k = prc[e] ((uniques.key?(k)) ? (dups << k; uniques.delete(k)) : uniques[k] = e) unless dups.include?(k) end uniques.values end end

An even more straightforward way is to use group_by

Set implements a collection of unordered values with no duplicates.

To me the difference between [1,1,2,2,3,3] and [1,2,3] is not []

It’s even worse that there’s no alternative method that does the unsurprising thing IMO.

Are you angry now? Because I’m angry.

You should see me doing a write up for a Ruby feature suggestion only to discover that Array#- is hijacked for non-mathematical reasons

Oh. Oh no. That's... not a thing that should be. People wonder why we can't get be more popular with science / math academics.

I don't think this is a good overload of 'subtraction'1Olivier Lacan@olivierlacan·Jan 14, 2019Yup. I don’t either.

but not as two methods called Array#- and Array#difference. As something like Array#set_difference maybe, or even Array#subtract_all, maybe.

One may expect Array#- to behave like mathematical subtraction or difference when it doesn't. One could be forgiven to expect the following behavior: [1,1,2,2,3,3,4,4] - [1,2,3,4] => [1,2,3,4]

I'll freely admit I was surprised by this behavior myself since I needed to obtain an Array with only one instance of each item in the argument array removed.

If you answer is yes, then we are doing this wrong because subset? or part_of method should be in a parent class (maybe Enumerable class ) in order for it to work for subset, array, hash and any data structure that inherit from it Enumerable.

Arrays are not sets. Trying to treat them as if they are is an error, and will create subtle problems. What should be the result of the following operations? [1, 1] | [1] [1] | [1, 1] Of course, there are more interesting examples. These two are to get you started. I don't care what the results currently are. I don't care what you think they should be. I can present extremely strong arguments for various answers. For this reason, I believe that #| is an ill-defined concept. Generalizing an ill-defined concept is a world of pain. If you insist on treating objects of one class as if they were members of a different class, there should be bumps in the road to at least warn you that maybe this is a bad idea. I'm not going to argue that we should remove or deprecate #|. I don't think of myself as a fanatic. But encouraging this sort of abuse of the type system just creates problems.

I do not understand why concat modify the array, as most of the method of the Array class has a ! method for that. Should I also introduced a concat! method?

call run[] ( or run.call/run.()

However, distributing such Ruby apps to inexperienced end users or non-Ruby-programmer end users is problematic. If users have to install Ruby first, or if they have to use RubyGems, they can easily run into problems. Even if they already have Ruby installed, they can still run into problems, e.g. by having the wrong Ruby version installed. The point is, it's a very real problem that could harm your reputation.

old_log_entries = old_log.split /(?=commit [0-9a-f]{40})/ # Lookahead assertions FTW

old_log.split /(?=commit [0-9a-f]{40})/ # Lookahead assertions FTW

Programming languages These will probably expose my ignorance pretty nicely.