puts "Hello, World!".webp){kind=logo}
Ask the right questions to secure the right Crystal talent among an increasingly shrinking pool of talent.
The Crystal programming language, first introduced in 2014 by Ary Borenszweig, Juan Wajnerman and a team of contributors, is a statically-typed, compiled language with syntax similar to Ruby. It is designed to provide the expressiveness of scripting languages with the efficiency and performance of compiled languages. Crystal's unique feature is its powerful type inference which allows developers to write code without specifying types explicitly. The language supports concurrent and parallel execution using fibers for lightweight concurrency while maintaining simplicity in syntax. As an open-source project, it has been developed collaboratively on GitHub by numerous contributors worldwide.
The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.
Crystal uses a concurrency model called CSP (Communicating Sequential Processes). It uses 'fibers' which are lightweight threads, to achieve concurrency.
In Crystal, nil values are handled using the '?' operator. This operator allows a variable to be of a certain type or nil.
While Crystal and Ruby have similar syntax, Crystal is statically typed and compiled, which makes it faster. Ruby, on the other hand, is dynamically typed and interpreted.
Crystal language has several key features including static type checking, C bindings, concurrency model, powerful macro system, and it's compiled.
Crystal is a statically typed, compiled, general-purpose programming language that has syntax similar to Ruby. It's designed to be easy to read and fast to execute.
Software development often involves teamwork. A candidate who can work well in a team will likely be more productive and contribute more to the project.
Good problem-solving skills are vital for any developer. It shows that they can think logically and come up with efficient solutions to coding problems.
This is important because it shows that the candidate has a broad understanding of programming languages and can leverage the strengths of Crystal while avoiding its limitations.
Being able to debug and optimize code is a critical skill for any developer. It shows that they understand the language in depth and can ensure that the code runs smoothly.
Experience with using Crystal in real-world applications or projects is a strong indicator of the candidate's ability to apply their skills in a practical context.
The candidate should be able to demonstrate a deep understanding of Crystal's syntax and its unique features. This is essential for writing efficient and effective code.
The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.
Inheritance in Crystal is implemented using the '<' operator. The child class inherits all the methods and properties of the parent class, and can also override them.
'==' is used for equality comparison while '===' is used for case equality, or to check if an object belongs to a certain type or range.
In Crystal, exceptions are handled using the 'begin', 'rescue', 'ensure', and 'end' keywords. You can define custom exceptions by creating a class that inherits from the 'Exception' class.
Macros in Crystal are powerful tools that allow you to avoid boilerplate code. They are executed at compile time and can generate methods, types, and perform other transformations on the code.
In Crystal, a class is defined using the 'class' keyword followed by the class name. The properties and methods are then defined within the class.
At this stage, a skilled Crystal engineer should demonstrate proficiency in the Crystal language, excellent problem-solving abilities, and deep understanding of web development principles. Red flags could include lack of knowledge in Ruby (since Crystal is heavily influenced by it) or inability to explain complex concepts clearly.
puts "Hello, World!"x = 10
y = 20
z = (x == y) ? "Equal" : "Not Equal"
puts znumbers = [1, 2, 3, 4, 5]
numbers.map! { |num| num * 2 }
puts numbersspawn do
puts "Hello from a thread"
end
puts "Hello from the main thread"class Person
def initialize(@name : String)
end
def greet
puts "Hello, #{@name}"
end
end
john = Person.new("John")
john.greetdef fibonacci(n : Int32)
return n if n <= 1
fibonacci(n - 1) + fibonacci(n - 2)
end
puts fibonacci(6)The final few interview questions for a Crystal candidate should typically focus on a combination of technical skills, personal goals, growth potential, team dynamics, and company culture.
Crystal is a compiled language, so it's generally faster than interpreted languages. However, performance can be affected by factors such as algorithmic complexity, memory usage, and I/O operations.
Dependencies in a Crystal project are managed using a 'shard.yml' file. This file lists the project dependencies and their versions. The 'shards' command is then used to install the dependencies.
'include' is used to add instance methods to a class, while 'extend' is used to add class methods.
In Crystal, a multidimensional array can be created by nesting arrays within an array. Each nested array can be of any length, allowing for non-rectangular arrays.
Crystal supports several data types including Integers, Floats, Booleans, Strings, Arrays, Hashes, Tuples, Ranges, and more.
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