Ruby vs CoffeeScript

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 CoffeeScript, there's never really a question of what is going on. If you're worried that something went wrong in the compilation process, the output is very human readable and mostly 1 to 1 with the CoffeeScript code, making debugging easier as the code that is being executed by the interpreter can be double checked.

CoffeeScript is the most popular of the compile to Javascript languages, so long term support is much less of a worry than with others.

It also means there are many plugins and tools for integrating it into many different build systems, giving it it nearly universal support.

Javascript is a very verbose language so CoffeeScript's goal is to lighten it to make it less tedious.

Various design choices are built around making CoffeeScript more terse with things like optional parenthesis in function calls, cleaner function declarations, no curly braces, and significant white space. Because Javascript can get pretty deeply nested at times, having a lightweight syntax helps with readability.

The result is a language with a minimalistic syntax with lots of syntax sugar.

The golden rule of CoffeeScript is: "It's just JavaScript". The code compiles one-to-one into the equivalent JS, and there is no interpretation at runtime. You can use any existing JavaScript library seamlessly from CoffeeScript (and vice-versa). The compiled output is readable and pretty-printed, passes through JavaScript Lint without warnings, will work in every JavaScript runtime, and tends to run as fast or faster than the equivalent handwritten JavaScript.

CoffeeScript adds syntax that is not only more terse than javascript, smoothing over the rough edges, but also enforces a more human readable syntax to the point where a non-programmer can understand some logic.

Many programmers that are not use to coffeescripts syntax will find it foreign if they don't read the single page API, but generally it is quick to understand and although self documenting code is a myth coffeescript is definitely very close.

if hungry then eat food for food in fridge when food isnt poison and it isnt bedtime

Seems a lot more concise and comprehensible to many programmers and most others than the alternative syntax:

var food, i, len;

if (hungry) {
  for (i = 0, len = fridge.length; i < len; i++) {
    food = fridge[i];
    if (food !== poison && it !== bedtime) {
      eat(food);
    }
  }
}

Passing functions as callbacks is central to how Javascript is written, but the default syntax for functions is very verbose and hard to read. Various CoffeeScript syntax decisions help with ease of writing and reading functions.

The most obvious change is that the function keyword is changed from function to ->. Writing out the word function is very clunky especially when you need to use multiple nested functions.

One of the more opinionated choices of CoffeeScript is the use of significant whitespace, and optional parens around function arguments. While this can be used poorly, it can also be used to great effect with nested functions. For example, a function that takes an object that defines anonymous functions will end in a mess of parens and curly braces:

asyncAction({
  success: function(data){ /* handle data */ },
  error: function(error){ /* handle errors */ }
});

In CoffeeScript you could rewrite this as:

asyncAction
  success: (data) -> /* handle data */
  fail: (error) -> /* handle errors */

Other helpful features are automatic returning of the last statement to make short anonymous functions easier so (a, b) -> a+b would replace function (a, b) { return a+b; }, as well as binding functions to the current context object with =>.

Because Javascript functions can take variable amounts of parameters, it is helpful to be able to use splats to extract an array of arguments in a function.

For example, if you have a function like: (a, b, rest...) ->any amount of parameters sent to the function after a, b will be stored in an array in the variable rest. You can also put splats at the start or middle of the arguments list, such as (a, middle..., b) ->.

When calling a function you can use a splat to apply an array as arguments as well.

Even for loops and if statements. For example, to get mapped array, you don't have to use any Array methods, just the language features:
food = ( stuff for stuff in fridge when stuff.isEatable() )

CoffeeScript was created by a Ruby programmer and a number of syntax features are modelled on Ruby equivalents, so will be familiar to Ruby programmers. For example, implicit returns, i.e. the last variable of each function is implicitly returned, so "return" keyword need not be present.

Skip the documentation build, just write documentation with literate CoffeeScript.

CoffeeScript has a literate mode which let's you use markdown (used by almost everything, such as reddit, github, stack exchange, etc) with code indented how you would normally in markdown and simply enables you to run the code.

This enables you to quickly write FORMATTED, custom documentation that's easily displayed with no build step for the documentation.

With source maps, you can get the proper location of where an error occurred directly in precompiled code, making it easier to debug without the tedious step of translating the compiled code back to the original code in your head.

Having indention-based code blocks is particularly helpful in JavaScript because of its functional callback based nature. In JavaScript you find yourself writing functions within object and passing functions to functions. You can find statements ending with a confusing melange of braces like )}})}). With significant whitespace, most of the needs for braces go away.

Easy to read and easy to work with structures like list.