Ruby vs D

Ruby is one of the most popular languages for developing web sites. As a result, there's an abundant amount of documentation, sample code, and libraries available for learning the language and getting your project up and running. The most popular features are just 'gem install' away. Additionally, it is easier to find Ruby jobs because of this.

Ruby has a very clean syntax that makes code easier to both read and write than more traditional Object Oriented languages, such as Java. For beginning programmers, this means the focus is on the meaning of the program, where it should be, rather than trying to figure out the meaning of obscure characters.

presidents = ["Ford", "Carter", "Reagan", "Bush1", "Clinton", "Bush2"]
for ss in 0...presidents.length
    print ss, ": ", presidents[presidents.length - ss - 1], "\n";
end

Ruby has a large ecosystem of tools and libraries for just about every use. Such as ORMs (Active Record, DatabMapper), Web Application Frameworks(Rails, Sinatra, Volt), Virtualization Orchestration(docker-api, drelict), CLI tools(Thor, Commando), GUI Frameworks(Shoes, FXRuby) and the list goes on. If you can think of it, there is probably a gem for that ( and if not you can create your own and share with the community).

The Ruby language is equipped with the necessary features to learn the essence of algorithms.

In online playground environments like ideone.com, measures have been taken to prevent beginners from going astray by restricting the use of external libraries such as Python's NumPy and SymPy.
Even in such constrained Ruby execution environments, the required features for learning algorithms are fully available.

Many of the algorithms that should be learned are documented in the book "Hello Ruby: Adventures in Coding." For example, the cake serving problem in the book leads to topological sorting, which is a graph theory concept useful in project management for creating Gantt charts.

To evaluate the effectiveness of algorithms with a level of complexity comparable to topological sorting,
it is necessary to be able to solve mathematical computation problems up to the high school level easily.
As shown in the table below, using only Ruby's standard library, it is possible to solve high school-level math problems effortlessly.
However, other programming languages may not be able to perform such computations in online playground environments.

To experience the superior performance of algorithms, it is important to challenge oneself by reimplementing good algorithms. Ruby's standard library includes implementations of excellent algorithms. For instance, the algorithm for solving linear equations, which has been widely known since the era of Fortran, is used within the code of SolvingLinearEquations through the "/" operator. Reimplementing code from Ruby's standard library serves as an excellent learning resource with high reusability and efficiency.

The SolvingLinearEquations function mentioned above demonstrates the benefits of duck typing and forced type conversion between objects of different types in arithmetic operations. While Rust also has features like duck typing, the implementation of "forced type conversion" is still far from being realized.

# Title: "(1) Cake Serving Procedure Problem"
require 'tsort'

class Hash
  include TSort
  alias tsort_each_node each_key
  def tsort_each_child(node, &block)
    fetch(node).each(&block)
  end
end

puts 'Tasks'
task_names = {
  'A' => 'Arrange the plates.',
  'B' => 'Set the spoons.',
  'C' => 'Place the birthday cake on the table.',
  'D' => 'Spread the tablecloth.'
}
p task_names

puts 'Preceding Tasks'
preceding_tasks = {
  'A' => ['D'],
  'B' => ['C', 'A'],
  'C' => ['A', 'D'],
  'D' => []
}

steps = preceding_tasks.strongly_connected_components
puts 'The appropriate steps are as follows:'
steps.each do |task_candidates|
  p task_candidates.map { |task| [task, task_names[task]] }
end

p "#(2) Equation Solving Rule"
def SolvingLinearEquations(y, a, b)
   x = (y - b) / a
end

p "(2-1) Real Solution", SolvingLinearEquations(1.0, 5, 0.5)
# => 0.1

p "(2-2) Fraction Solution", SolvingLinearEquations(Rational(1, 1), Rational(5, 1), Rational(1, 2))
# =>  (1/10)

p "(2-3) Imaginary Solution", SolvingLinearEquations(1 + 1i, 5, 1.0 / (2 + 2i))
# => (0.15+0.25i)

p "(2-4) Complex & Fraction Solution", SolvingLinearEquations(Rational(1 + 1i, 1), Rational(5, 1), Rational(1, 2 + 2i))
# => ((3/20)+(1/4)*i)

p "(2-5) Matrix Solution with Large Integers", 
   SolvingLinearEquations(Matrix[[Rational(1234567890123456789890, 1), Rational(0, 1)]],
                                                Matrix[[Rational(1234567890123456789890, 1), Rational(1234567890123456789890 * 2, 1)],
                                                             [Rational(1234567890123456789890, 1), Rational(1234567890123456789890 * 3, 1)]],
                                                Matrix[[Rational(1234567890, 1), Rational(123456789, 1)]] )
# => Matrix[[(3703703670366790122789/1234567890123456789890), (-2469135780244567900789/1234567890123456789890)]]

p "(2-7) Matrix Solution with Large Integers, Complex Numbers, and Fractions", 
     SolvingLinearEquations(Matrix[[Rational(1234567890123456789890, 1i), Rational(0, 1)]],
                                                 Matrix[[Rational(1234567890123456789890, 1), Rational(1234567890123456789890 * 2, 1i)],
                                                               [Rational(1234567890123456789890, 1), Rational(1234567890123456789890 * 3, 1i)]],
                                                Matrix[[1234567890, 0 + 1i]] )
# => Matrix[[((-3703703671/1234567890123456789890)-(3/1)*i), ((2469135781/1234567890123456789890)+(2/1)*i)]]

Lays out an easy to follow and opinionated MVC pattern that teaches best practices through necessity.

It's the fore-runner and trend setter for TDD.

Object oriented programming is one of the most important concepts in programming.

Meta-programming provides efficiency and freedom.

No indentation increase development efficiency.

With few exceptions, D will either compile C code to work exactly as when compiled as C, or it won't compile - it won't quietly change the semantics of C code and give unexpected results. This means that D contains an improved C, as it fails compilation where type safety is missing in C.

This allows learning the same machine operations available in C and other low-level languages.

When you're just starting out, dealing with manual memory management and its bugs is a huge pain! D is garbage collected by default, which removes a huge class of things that could go wrong. And later on, if you decide you don't want or need the GC, you can turn it off.

D is usually up to 10 times faster than C++. Having a language that compiles this fast means that you are free to write highly optimized code because of the relatively low cost of experimentation.

D provides unittest blocks to insert code that verifies functions preform their expected behavior and document edge cases. Since these are enabled with a compiler switch, there is no need to teach new programmers how to install new libraries and import modules, instead training on test driven design can start from the very first function.

D provides a structure that builds on C's arrays called slices. A slice is a segment of an array that tracks the pointer and the length of the segment.

Slices are extremely powerful because they combine the protection of knowing the length of the data with the garbage collector that manages the memory backing that data, thus avoiding most memory corruption issues.

For a new user adding types can feel tedious, and takes focus off the meaning of the code, but they are also important for checking logic. D provides static types, and a good system to infer types, so types are checked when calling functions, but do not need to be specified everywhere, making it feel more dynamic.

The compiler can check that functions don't have side effects, extremely important for functional programming in concurrent scenarios, and can check immutability.

Therefore, the compiler will prove that your programs are functionally pure and respect immutable data, if you want it to.

Because all types can be treated as objects, all files can call functions in the same manner -- even stdin and stdout. stdout.writeln(); stdin.readln(); file.writeln(); file.readln();

D practically has the same memory structure as C and C++; all D does it build a structure around that. The entire C standard library is accessible at no cost (syntactic or speed) and it's being worked on allowing the same for the C++ standard library.

Supports first-class functionality for both concurrency and parallelism, offered as part of the standard library.

if (exists(file)) {} may be written as if (file.exists) {}.

writeln(file); may be written as file.writeln();

isDivisibleBy(10, 2); may be written as 10.isDivisibleBy(2);

writeln(isEven(add(5, 5))); may be written as 5.add(5).isEven().writeln();