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Chez Scheme is a high-performance implementation of the Scheme programming language, developed by Cadence Research Systems and later acquired by Cisco Systems. Initially released in 1984, it was one of the first commercial Scheme implementations. The language is known for its efficient compilation, advanced run-time system, and support for concurrent and parallel programming. It has been widely used in research, education, and industrial applications. Its source code was made open-source by Cisco in 2016, allowing a wider community to contribute to its development.

Ask the right questions secure the right Chez Scheme talent among an increasingly shrinking pool of talent.

First 20 minutes

General Chez Scheme app knowledge and experience

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

What are the basic data types in Chez Scheme?

The basic data types in Chez Scheme include integers, reals, characters, strings, symbols, pairs, vectors, and procedures.

How would you define a function in Chez Scheme?

In Chez Scheme, you define a function using the 'define' keyword. For example, '(define (add x y) (+ x y))' defines a function that adds two numbers.

What is the purpose of the 'lambda' keyword in Chez Scheme?

The 'lambda' keyword is used to create anonymous functions in Chez Scheme. These functions can be used as arguments to other functions or returned as results.

How would you implement recursion in Chez Scheme?

Recursion in Chez Scheme can be implemented by having a function call itself. For example, a recursive function to calculate factorial would be '(define (fact n) (if (<= n 1) 1 (* n (fact (- n 1)))))'.

What are the uses of 'car' and 'cdr' functions in Chez Scheme?

'car' and 'cdr' are used to access the elements of a pair. 'car' returns the first element and 'cdr' returns the second element.

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What you’re looking for early on

Does the candidate demonstrate a solid understanding of Chez Scheme?

Can the candidate code in Chez Scheme?

Is the candidate able to debug and solve problems in Chez Scheme?

Does the candidate have experience with version control systems?

Next 20 minutes

Specific Chez Scheme 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.

How would you create a list in Chez Scheme?

A list in Chez Scheme can be created using the 'list' function. For example, '(list 1 2 3)' creates a list of three elements.

Describe the difference between 'let' and 'let*' in Chez Scheme.

'let' and 'let*' both bind variables to values, but 'let*' binds them sequentially, allowing later bindings to refer to earlier ones. 'let' binds all variables simultaneously, so later bindings cannot refer to earlier ones.

What is tail recursion in Chez Scheme and why is it important?

Tail recursion is a form of recursion where the recursive call is the last operation in the function. It's important because it allows the Scheme interpreter to optimize the recursion, using constant stack space.

How would you implement a higher-order function in Chez Scheme?

A higher-order function in Chez Scheme can be implemented by defining a function that takes another function as an argument or returns a function as a result. For example, '(define (apply-twice f x) (f (f x)))' is a higher-order function that applies a function twice to an argument.

What are macros in Chez Scheme and how would you define one?

Macros in Chez Scheme are used to define new syntactic constructs. They are defined using the 'define-syntax' keyword. For example, '(define-syntax unless (syntax-rules () ((_ test exp) (if (not test) exp))))' defines an 'unless' macro.

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At this point, a skilled Chez Scheme engineer should demonstrate strong problem-solving abilities, proficiency in Chez Scheme 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 Chez Scheme.

What does this simple Chez Scheme code do?
(define (square x) (* x x))
This code defines a function named 'square' that takes one argument 'x' and returns the square of 'x'.
What will be the output of this Chez Scheme code?
(define (factorial n) (if (zero? n) 1 (* n (factorial (- n 1))))) (factorial 5)
This code defines a recursive function to calculate the factorial of a number. It then calls this function with the argument 5. The output will be 120, which is the factorial of 5.
What does this Chez Scheme code do?
(define (map f lst) (if (null? lst) '() (cons (f (car lst)) (map f (cdr lst)))))
This code defines a function 'map' that applies a function 'f' to each element of a list 'lst'. It returns a new list with the results.
What does this Chez Scheme code do?
(define (parallel-execute f g) (let ((t (thread (lambda () (f))))) (g) (thread-wait t)))
This code defines a function 'parallel-execute' that takes two functions 'f' and 'g' as arguments. It creates a new thread to execute function 'f' and then executes function 'g' in the main thread. It waits for the thread executing 'f' to finish before returning.

Wrap-up questions

Final candidate for Chez Scheme 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 Chez Scheme application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you handle errors in Chez Scheme?

Errors in Chez Scheme can be handled using the 'with-exception-handler' function, which installs a procedure to be called when an exception is raised.

Describe the difference between 'eq?', 'eqv?', and 'equal?' in Chez Scheme.

'eq?' tests if two objects are the same, 'eqv?' tests if two objects are equivalent in a way that respects the data type, and 'equal?' tests if two objects are structurally equivalent.

How would you implement a mutable data structure in Chez Scheme?

Mutable data structures in Chez Scheme can be implemented using 'set-car!' and 'set-cdr!' to modify pairs, or 'vector-set!' to modify vectors.

Chez Scheme application related

Product Perfect's Chez Scheme development capabilities

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

Chez Scheme Consultive assessments

Chez Scheme Application Conversion Assessment Chez Scheme Application Integration Assessment Chez Scheme Data & Database Integration Assessment

Custom Chez Scheme development projects

Custom Chez Scheme App Conversion Chez Scheme Custom App Development Process App UI Design for Chez Scheme Facelifts

Hiring guide for Chez Scheme Engineers

Chez Scheme Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

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

Chez Scheme Consultive assessments

Custom Chez Scheme development projects