Hiring guide for Qi (programming language) Engineers

Qi (programming language) Developer Hiring Guide

Qi is a functional programming language that was designed to provide a platform for both practical and theoretical computation. It was developed by Mark Tarver, who introduced it in 2005. Qi is built on Lisp, one of the oldest high-level programming languages still in widespread use today. The language supports first-class functions, lexical closures, list comprehensions and pattern matching. It also has a type system which includes parametric polymorphism and optional static typing. The type inference mechanism of Qi allows programmers to write code without having to explicitly declare types for every variable or function parameter. One unique feature of Qi is its support for theorem proving and formal verification techniques within the language itself. This makes it particularly suitable for applications where correctness is critical. Qi runs on several platforms including Windows, Linux, and Mac OS X as it's implemented as an extension to Common Lisp. However, development of Qi has been discontinued since 2010 when Shen programming language was introduced as its successor by the same author.

Ask the right questions secure the right Qi (programming language) talent among an increasingly shrinking pool of talent.

First 20 minutes

General Qi (programming language) app knowledge and experience

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

How would you define Qi?
Qi is a functional programming language that is mainly used for symbolic computation. It is statically typed and incorporates pattern matching and predicate dispatch features.
What are the main features of Qi?
Qi has several features including static typing, pattern matching, predicate dispatch, and a module system. It also supports first-class functions and macros.
How would you declare a variable in Qi?
In Qi, you can declare a variable using the 'define' keyword. For example, '(define x 10)' declares a variable x and assigns it the value 10.
What are the data types supported by Qi?
Qi supports several data types including integers, floats, strings, lists, and functions.
Describe the difference between 'define' and 'let' in Qi.
'define' is used to declare a global variable, while 'let' is used to declare a local variable. The scope of a variable declared with 'let' is limited to the block in which it is declared.
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What you’re looking for early on

Does the candidate have a solid understanding of Qi programming language?
Can the candidate solve complex problems using Qi?
Is the candidate familiar with the best practices in Qi programming?
How well does the candidate understand data structures and algorithms?

Next 20 minutes

Specific Qi (programming language) 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 define a function in Qi?
In Qi, a function is defined using the 'define' keyword followed by the function name, parameters, and body. For example, '(define (add x y) (+ x y))' defines a function 'add' that takes two parameters 'x' and 'y' and returns their sum.
What is pattern matching in Qi?
Pattern matching in Qi is a feature that allows a function to have multiple definitions based on the pattern of the arguments. The correct definition is chosen based on the pattern that the arguments match.
How would you implement recursion in Qi?
Recursion in Qi can be implemented by having a function call itself. For example, the factorial function can be implemented as '(define (factorial n) (if (<= n 1) 1 (* n (factorial (- n 1)))))'.
What is predicate dispatch in Qi?
Predicate dispatch in Qi is a feature that allows a function to have multiple definitions based on the truth value of a predicate. The correct definition is chosen based on the predicate that returns true for the given arguments.
How would you handle exceptions in Qi?
Exceptions in Qi can be handled using the 'catch' function. The 'catch' function takes two arguments: a function that may throw an exception, and a function that handles the exception.
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The ideal back-end app developer

What you’re looking to see on the Qi (programming language) engineer at this point.

At this point, a skilled Qi (programming language) engineer should demonstrate strong problem-solving abilities, proficiency in Qi (programming language) 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 Qi (programming language).

What does this simple Qi code do?
(define (hello-world) (println "Hello, World!"))
This code defines a function `hello-world` that prints the message `Hello, World!` when called.
What will be the output of this Qi code?
(define (square x) (* x x)) (square 5)
This code defines a function `square` that takes a number and returns its square. It then calls this function with the argument `5`. The output will be `25`.
What does this Qi code do with a list?
(define (sum-list xs) (fold + 0 xs)) (sum-list (list 1 2 3 4 5))
This code defines a function `sum-list` that takes a list and returns the sum of its elements using the `fold` function. It then calls this function with a list of numbers from 1 to 5. The output will be `15`.
What does this Qi code do regarding threading?
(define (thread-sum xs) (parallel-map + xs)) (thread-sum (list 1 2 3 4 5))
This code defines a function `thread-sum` that takes a list and returns a new list with each element increased by 1 using the `parallel-map` function in a concurrent way. It then calls this function with a list of numbers from 1 to 5. The output will be a list of numbers from 2 to 6.

Wrap-up questions

Final candidate for Qi (programming language) 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 Qi (programming language) application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

What are macros in Qi and how would you define one?
Macros in Qi are functions that are evaluated at compile time. A macro is defined using the 'defmacro' keyword. For example, '(defmacro (square x) `(* ,x ,x))' defines a macro 'square' that squares its argument.
How would you implement a higher-order function in Qi?
A higher-order function in Qi can be implemented by defining a function that takes a function as an argument or returns a function. For example, '(define (apply-twice f x) (f (f x)))' defines a higher-order function 'apply-twice' that applies a function 'f' twice to an argument 'x'.
Describe the difference between eager and lazy evaluation in Qi.
In eager evaluation, which is the default in Qi, expressions are evaluated as soon as they are bound to a variable. In lazy evaluation, expressions are not evaluated until their values are needed. Lazy evaluation can be enabled in Qi using the 'lazy' keyword.

Qi (programming language) application related

Product Perfect's Qi (programming language) development capabilities

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

Qi (programming language) Consultive assessments

Custom Qi (programming language) development projects

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