Product Perfect

Scheme is a high-level, functional programming language that belongs to the Lisp family of languages. It was developed in the 1970s at the Massachusetts Institute of Technology (MIT) and is known for its simplicity, efficiency, and flexibility. Scheme supports first-class procedures, lexical scoping, and continuations. It also allows for a high degree of interactivity and is often used in teaching computer science concepts due to its minimalist design. Scheme is widely used in research, education, and industrial applications. It has a standard specification called RnRS and has various implementations including Racket, Chicken Scheme, and Guile.

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

First 20 minutes

General Scheme app knowledge and experience

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

How would you define a variable in Scheme?

To define a variable in Scheme, you would use the 'define' keyword followed by the variable name and its value. For example: (define x 10).

What are the primitive data types in Scheme?

The primitive data types in Scheme are integers, real numbers, characters, strings, and booleans.

How would you create a list in Scheme?

You create a list in Scheme using the 'list' function. For example: (list 1 2 3) would create a list with elements 1, 2, and 3.

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

'let' and 'let*' are used to bind variables. The difference is that 'let*' binds variables sequentially, allowing subsequent bindings to refer to previously bound variables. 'let' does not allow this.

How would you implement recursion in Scheme?

Recursion in Scheme is implemented by defining a function that calls itself. For example, a recursive function to calculate factorial would call itself with a smaller argument until it reaches the base case.

The hiring guide has been successfully sent to your email address.

Oops! Something went wrong while submitting the form.

What you’re looking for early on

Does the candidate have a strong understanding of the Scheme programming language?

Has the candidate demonstrated problem-solving skills?

Can the candidate work well in a team?

Does the candidate show a willingness to learn and adapt?

Next 20 minutes

Specific 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.

What are some features of functional programming in Scheme?

Some features of functional programming in Scheme include first-class functions, higher-order functions, and recursion. Scheme also supports immutability and expressiveness through its simple syntax.

How would you create a higher-order function in Scheme?

A higher-order function in Scheme is created by defining a function that takes another function as an argument or returns a function. For example, the 'map' function is a higher-order function that applies a given function to each element of a list.

Describe the difference between 'cons', 'car', and 'cdr' in Scheme.

'cons' is a function that takes two arguments and returns a pair. 'car' returns the first element of a pair or list, and 'cdr' returns the rest of the elements in a pair or list.

How would you use the 'apply' function in Scheme?

The 'apply' function in Scheme is used to apply a function to a list of arguments. For example, (apply + (list 1 2 3)) would return the sum of 1, 2, and 3.

What are continuations in Scheme and how are they used?

Continuations in Scheme represent the rest of a computation from a certain point. They can be used for advanced control structures, such as implementing loops or handling exceptions.

The hiring guide has been successfully sent to your email address.

Oops! Something went wrong while submitting the form.

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

What does this simple 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 the following Scheme code?
(define (factorial n) (if (<= n 1) 1 (* n (factorial (- n 1))))) (factorial 5)
The output of this code will be '120'. The code defines a recursive function to calculate the factorial of a number. It then calls this function with the argument '5'.
What does the following 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 the following Scheme code do?
(define (parallel-execute f g) (thread (lambda () (f))) (thread (lambda () (g))))
This code defines a function 'parallel-execute' that takes two functions 'f' and 'g' as arguments. It creates two separate threads to execute these functions concurrently.

Wrap-up questions

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

How would you implement error handling in Scheme?

Error handling in Scheme can be implemented using the 'with-exception-handler' function. This function takes two arguments: the handler function and the body of code where exceptions might occur.

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

These are all comparison functions in Scheme. 'eq?' tests if two objects are the same, 'eqv?' tests if two objects are equivalent, and 'equal?' tests if two objects are structurally equivalent.

How would you implement a macro in Scheme?

Macros in Scheme can be implemented using the 'define-syntax' keyword. A macro is a way to define new syntax or new constructs in the language.

Scheme application related

Product Perfect's Scheme development capabilities

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

Scheme Consultive assessments

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

Custom Scheme development projects

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

Hiring guide for Scheme Engineers

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 Scheme engineer at this point.

Scheme Consultive assessments

Custom Scheme development projects