Hiring guide for Modula-2 Engineers

Modula-2 Developer Hiring Guide

Modula-2 is a general-purpose, high-level programming language developed in the late 1970s by Niklaus Wirth, a Swiss computer scientist. It was designed as a successor to Pascal, with the aim of making it possible to write complex systems and operating systems in a more modular and therefore manageable way. Modula-2 introduced the concept of modules, which allow programmers to encapsulate data and functions into separate units that can be compiled separately. This feature greatly improves code organization and reusability. The language supports both structured and object-oriented programming paradigms, offering features like strong type checking, concurrency (multi-threading), hardware access, exception handling, and generic programming. Despite its powerful features, Modula-2 is known for its simplicity and ease of learning. While not as popular as languages like C or Java today, Modula-2 has been influential in the design of later languages such as Ada, Oberon, Go and Swift. It is still used in some niches like education or embedded systems development where its simplicity and efficiency are appreciated.

Ask the right questions secure the right Modula-2 talent among an increasingly shrinking pool of talent.

First 20 minutes

General Modula-2 app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Modula-2 application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you declare a constant in Modula-2?
In Modula-2, a constant is declared using the CONST keyword followed by the constant name, the '=' operator, and the constant value. For instance, 'CONST pi = 3.14159;'.
What are the basic data types in Modula-2?
The basic data types in Modula-2 are INTEGER, REAL (for floating point numbers), BOOLEAN (for truth values), CHAR (for characters), and CARDINAL (for non-negative integers).
Describe the difference between the WHILE and REPEAT statements in Modula-2.
The WHILE statement in Modula-2 is a pre-test loop, meaning it checks the condition before executing the loop body. If the condition is false at the start, the loop body may not execute at all. On the other hand, the REPEAT statement is a post-test loop, meaning it executes the loop body first and then checks the condition. So, the loop body will always execute at least once.
How would you implement procedure overloading in Modula-2?
Procedure overloading is not directly supported in Modula-2. However, you can achieve a similar effect by passing different types of parameters or varying the number of parameters.
What are the visibility rules in Modula-2?
In Modula-2, the visibility of an entity is determined by where it is declared. If it's declared within a procedure, it's visible only within that procedure. If it's declared within a module but outside any procedure, it's visible to all procedures within the module. If it's declared in the interface section of a module, it's visible to other modules that import that module.
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What you’re looking for early on

Does the candidate demonstrate a solid understanding of Modula-2?
Has the candidate provided examples of past projects using Modula-2?
Is the candidate able to solve problems and debug in Modula-2?
Is the candidate familiar with the latest trends and updates in the Modula-2 language?

Next 20 minutes

Specific Modula-2 development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

Describe the difference between the ARRAY and RECORD data types in Modula-2.
An ARRAY in Modula-2 is a collection of elements of the same type, indexed by integers. A RECORD, on the other hand, is a collection of elements possibly of different types, identified by field names.
How would you handle exceptions in Modula-2?
Modula-2 provides a mechanism for exception handling with the use of the TRY...EXCEPT construct. The code that may raise an exception is put in the TRY block, and the code to handle the exception is put in the EXCEPT block.
What are the rules for identifier names in Modula-2?
In Modula-2, identifier names must begin with a letter and can be followed by any combination of letters, digits, and underscores. They are case sensitive.
Describe the difference between a procedure and a function in Modula-2.
In Modula-2, a procedure is a group of statements that performs a task and does not return a value. A function, on the other hand, is a group of statements that performs a task and does return a value.
How would you implement recursion in Modula-2?
Recursion in Modula-2 can be implemented by having a procedure or function call itself. Care must be taken to ensure that the recursion has a base case to prevent infinite recursion.
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The ideal back-end app developer

What you’re looking to see on the Modula-2 engineer at this point.

At this point, a skilled Modula-2 engineer should demonstrate strong problem-solving abilities, proficiency in Modula-2 programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Modula-2.

What does this simple Modula-2 code do?
MODULE HelloWorld;
  WriteString('Hello, World!');
END HelloWorld.
This code snippet outputs the string 'Hello, World!' to the console.
What does this Modula-2 syntax represent?
MODULE Factorial;
  n, fact: INTEGER;
  n := 5;
  fact := 1;
  WHILE n > 0 DO
    fact := fact * n;
  WriteInt(fact, 0);
END Factorial.
This code calculates the factorial of 5, which is 120. The result is then printed to the console.
What does this Modula-2 code do with the array?
MODULE ArraySum;
  arr: ARRAY [1..5] OF INTEGER;
  sum, i: INTEGER;
  FOR i := 1 TO 5 DO
    arr[i] := i;
  sum := 0;
  FOR i := 1 TO 5 DO
    sum := sum + arr[i];
  WriteInt(sum, 0);
END ArraySum.
This code initializes an array with 5 elements, each element being its index. It then sums up all elements of the array and prints the sum, which is 15, to the console.
What does this Modula-2 code do in regards to threading?
MODULE ThreadExample;
  t: Thread;
  WriteString('Hello from MyThread!');
END MyThread;
  t := CreateThread(MyThread);
END ThreadExample.
This code creates a new thread 't' that executes the procedure 'MyThread'. 'MyThread' simply outputs a string to the console. The main thread then waits for 't' to finish execution before it can continue.

Wrap-up questions

Final candidate for Modula-2 Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Modula-2 application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

What are the rules for string manipulation in Modula-2?
In Modula-2, strings are arrays of characters. They can be manipulated using standard array operations, as well as a few built-in procedures like LENGTH (to get the length of a string) and CONCAT (to concatenate two strings).
Describe the difference between strong and weak typing in Modula-2.
Modula-2 is a strongly typed language, meaning that the type of a variable is checked at compile time. This is in contrast to weak typing, where types may be implicitly converted or interpreted differently depending on the context.
How would you implement polymorphism in Modula-2?
Polymorphism is not directly supported in Modula-2. However, you can achieve a similar effect with the use of variant records, pointers, and procedure variables.

Modula-2 application related

Product Perfect's Modula-2 development capabilities

Beyond hiring for your Modula-2 engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Modula-2 projects, and can engage in multiple capacities.