Tocacar

$gen = (function() {
    yield 1;
    yield 2;
    // 3 is only returned after the generator has finished
    return 3;

})();

foreach ($gen as $val) {
    echo $val, PHP_EOL;

Tocacar

function printer() {
    echo "I'm printer!". PHP_EOL;

    while (true) {
        $string = yield;
        echo $string . PHP_EOL;
    }
}

$printer = printer();

Tocacar

function  counter($num) {
    for ($i = 1; $i < $num; $i++) {
        yield $i;
    }
}

foreach (counter(PHP_INT_MAX) as $count) {
    echo "Yield: " . $count . PHP_EOL;
}

Tocacar

function gen_one_to_three() {
    for ( $i = 1; $i <= 3; $i++ ) {
        yield $i;
        yield 'abc';
    }
}

$generator = gen_one_to_three();

foreach ( $generator as $value ) {

Tocacar

Class Person < ActiveRecord::ApplicationRecord
  validates :name, presence: true
  validates :date_of_birth, presence: true, if: create_stage > 1
  validates :ni_number, presence: true, if: create_stage > 2
end

Tocacar

class PersonValidator < ActiveModel::Validator
  def validate(record)
    @record = record
    __send__("validate_stage_#{@record.create_stage}")
  end

  private
  def validate_stage_1
    validate_present(:name)
  end

Tocacar

class Person < ApplicationRecord
  validates_with PersonValidator
end

Tocacar

Class Person < ActiveRecord::ApplicationRecord
  validates :name, presence: true
  validates :date_of_birth, presence: true, if: create_stage > 1
  Validates :ni_number, presence: true, if: create_stage > 2
end

Tocacar

Class Person < ActiveRecord::ApplicationRecord
  validates :name, date_of_birth, ni_number, presence: true
end

Tocacar

context 'stage 2' do
  let(:person)    { Person.new(create_stage: 2) }

  context 'both name and date of birth supplied' do
    it 'is valid' do
      person.name = 'John Smith'
      person.date_of_birth = Date.new(1990, 5, 12)
      expect(person).to be_valid
    end
  end