Ceylon Developer Hiring Guide

Hiring Guide for Ceylon Engineers

Ask the right questions to secure the right Ceylon talent among an increasingly shrinking pool of talent.

Ceylon, now known as Sri Lanka, was a British Crown colony off the southeastern coast of India from 1815 until it gained independence in 1948. The island's rich history includes periods of Portuguese and Dutch colonial rule before its transfer to the British Empire in 1802 under the Treaty of Amiens. Renowned for its production and exportation of tea, rubber, and cinnamon during colonial times, Ceylon played a significant role in global trade networks. Its strategic location also made it a crucial naval base during World War II. This historical information is derived from sources including Encyclopedia Britannica and Cambridge University Press publications on South Asian history.

First 20 minutes

General Ceylon knowledge and experience

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.

How would you define a function in Ceylon?

In Ceylon, a function is defined using the 'function' keyword followed by the function name, parameters in parentheses, and the function body enclosed in braces. For example: 'function myFunction() {}'

Describe the difference between 'value' and 'variable' in Ceylon.

'value' is used to declare immutable variables in Ceylon, which means their value cannot be changed once assigned. 'variable' is used to declare mutable variables, which means their value can be changed.

How would you declare a variable in Ceylon?

In Ceylon, variables are declared using the 'value' keyword for immutable variables and the 'variable' keyword for mutable variables. For example: 'value myValue = 10;' or 'variable myVariable = 10;'

What are the basic data types in Ceylon?

Ceylon has several basic data types including Integer, Float, Character, String, Boolean, and Byte.

How would you define a class in Ceylon?

In Ceylon, a class is defined using the 'class' keyword followed by the class name and the class body enclosed in braces. For example: 'class MyClass {}'

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What youre looking for early-on

Has the candidate shown a willingness to learn and grow?

This is important for staying updated with the latest technologies and best practices in software development.

Can the candidate adapt to new technologies and frameworks?

Being adaptable is crucial in the ever-evolving field of software development.

Does the candidate have a good understanding of software development principles?

This is important for writing efficient, maintainable code.

Is the candidate able to communicate effectively?

Communication skills are vital for understanding project requirements and collaborating with team members.

Does the candidate show a capacity for problem-solving?

Problem-solving skills are necessary for developers to find and fix issues in code.

Has the candidate demonstrated a strong understanding of the Ceylon language?

This is essential as it is the primary language they will be working with.

Next 20 minutes

Specific Ceylon development questions

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.

How would you create a generic class in Ceylon?

In Ceylon, a generic class is created by defining a class with one or more type parameters. For example: 'class MyClass<Element> {}'

What are higher-order functions in Ceylon?

Higher-order functions in Ceylon are functions that can accept other functions as parameters and/or return other functions as results.

Describe the difference between 'assert' and 'assert is' in Ceylon.

'assert' is used to ensure that a certain condition is true at a certain point in the program. 'assert is' is used to ensure that a certain value is of a certain type.

How would you handle exceptions in Ceylon?

In Ceylon, exceptions are handled using 'try', 'catch', and 'finally' blocks. The 'try' block contains the code that might throw an exception, the 'catch' block contains the code to handle the exception, and the 'finally' block contains the code that is always executed, whether an exception occurred or not.

What are tuples in Ceylon?

Tuples in Ceylon are a type of collection that can hold a fixed number of elements, each with its own type. They are defined using square brackets. For example: '[Integer, String] myTuple = [1, 'hello'];'

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The ideal back-end app developer

What you’re looking to see on the Ceylon engineer at this point.

At this stage, a skilled Ceylon engineer should exhibit a deep understanding of the Ceylon language, strong problem-solving abilities and effective communication skills. Red flags could include lack of practical experience, inability to explain complex concepts clearly or difficulty in answering technical questions.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Ceylon.

What does the following Ceylon code do?

value hello = "Hello, World!";
print(hello);

This code declares a string variable named 'hello' and assigns it the value 'Hello, World!'. It then prints the value of 'hello' to the console.

What will be the output of the following Ceylon code?

value numbers = {1, 2, 3, 4, 5};
value sum = numbers.reduce(0, plus);
print(sum);

This code declares a set of integers named 'numbers'. It then uses the 'reduce' function to sum up the numbers in the set. The result, which is 15, is then printed to the console.

What does the following Ceylon code do?

value numbers = {1, 2, 3, 4, 5};
value evens = numbers.filter((Integer i) => i%2==0);
print(evens);

This code declares a set of integers named 'numbers'. It then uses the 'filter' function to create a new set 'evens' that contains only the even numbers from 'numbers'. The 'evens' set is then printed to the console.

What does the following Ceylon code do?

shared void run() {
  for (i in 1..100) {
    print("Thread running: ``process.thread``");
  }
}

This code defines a function 'run' that prints a message to the console 100 times. The message includes the ID of the thread that is currently executing the function.

What does the following Ceylon code do?

class Point(shared Integer x, shared Integer y) {
  shared Integer distanceFromOrigin() =>
    (x^2 + y^2)^0.5;
}

This code defines a class 'Point' with two integer properties 'x' and 'y'. It also defines a method 'distanceFromOrigin' that calculates the distance of the point from the origin (0,0) using the Pythagorean theorem.

What will be the output of the following Ceylon code?

void printNumbers() {
  for (i in 1..5) {
    if (i%2==0) {
      continue;
    }
    print(i);
  }
}
printNumbers();

This code defines a function 'printNumbers' that prints the numbers from 1 to 5 to the console, but skips the even numbers due to the 'continue' statement. When the function is called, it will print '1', '3', and '5'.

Wrap-up questions

Final candidate for Ceylon role questions

The final few interview questions for a Ceylon candidate should typically focus on a combination of technical skills, personal goals, growth potential, team dynamics, and company culture.

Describe the difference between 'abstract' and 'formal' in Ceylon.

'abstract' is a keyword in Ceylon that is used to declare a class that cannot be instantiated. 'formal' is a keyword that is used to declare a method that must be implemented by any non-abstract subclass.

How would you use the 'satisfies' keyword in Ceylon?

The 'satisfies' keyword in Ceylon is used to specify that a class or interface conforms to a certain interface. For example: 'class MyClass satisfies MyInterface {}'

What are metamodel expressions in Ceylon?

Metamodel expressions in Ceylon are used to access the model of the program at runtime. They allow you to inspect the types, functions, classes, and other elements of the program.

Describe the difference between 'shared' and 'default' in Ceylon.

'shared' is a keyword in Ceylon that makes a declaration visible to other modules. 'default' is a keyword that specifies a default implementation of an interface method.

What is the purpose of the 'dynamic' block in Ceylon?

The 'dynamic' block in Ceylon is used to interact with JavaScript code. It allows the Ceylon code to call JavaScript functions and access JavaScript objects.

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Ceylon application related

Product Perfect's Ceylon development capabilities

Beyond hiring for your Ceylon engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Ceylon projects, and can engage in multiple capacities.