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

Frege is a non-strict, strongly-typed, functional programming language that is a Haskell for the Java Virtual Machine (JVM). Named after Gottlob Frege, a significant figure in the field of logic and mathematics, this language was developed to bring purely functional programing to the JVM. It closely follows the Haskell2010 standard and even shares its syntax and semantics. The Frege compiler translates Frege programs into Java, allowing seamless integration with any existing Java libraries. This unique feature makes it an attractive choice for developers seeking to leverage the robustness of JVM while enjoying the benefits of functional programming.

First 20 minutes

General Frege 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.

What are Algebraic Data Types in Frege?

Algebraic Data Types (ADTs) in Frege are a way of creating new data types. They can be either product types (data types with multiple parts) or sum types (data types that can be one of many possible variants).

How would you define a function in Frege?

In Frege, you define a function using the 'fun' keyword followed by the function name, parameters, and the equals sign, and then you write the function body. The return type of the function is inferred by the compiler.

Describe the difference between Lazy and Strict evaluation in Frege.

Lazy evaluation means that expressions are not evaluated until their results are needed. Strict evaluation means that expressions are evaluated as soon as they are bound to a variable. Frege uses strict evaluation by default but can also support lazy evaluation when needed.

What are the basic data types in Frege?

Frege has several basic data types including Int, Double, Char, and Bool, among others. It also supports complex data types like lists, tuples, and user-defined types.

How would you describe Frege's type inference?

Frege's type inference is strongly static, similar to Haskell. It uses the Hindley-Milner type system to infer the types of expressions without explicit type annotations.

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What youre looking for early-on

Does the candidate have a good understanding of how to test and debug Frege code?

Testing and debugging are important parts of the development process, so the candidate should be proficient in these areas to ensure the delivery of high-quality code.

Has the candidate shown the ability to write clean and maintainable code?

This is important as it ensures the code is easy to understand, modify, and debug by other team members.

Does the candidate have experience with functional programming paradigms?

Frege is a functional programming language, so experience with functional programming paradigms is a strong indicator of the candidate's potential proficiency with Frege.

Can the candidate effectively work with Frege's type system?

Understanding and effectively using Frege's type system is critical as it helps ensure data consistency and reliability.

Has the candidate demonstrated problem-solving abilities?

Problem-solving skills are crucial in any programming role, as they will need to troubleshoot and solve issues that arise during coding.

Does the candidate possess a sound understanding of Frege's syntax and semantics?

This is essential because Frege is a functional programming language and understanding its syntax and semantics is key to writing efficient and error-free code.

Next 20 minutes

Specific Frege 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.

What are Monads in Frege, and how would you use them?

Monads in Frege are a way of handling side effects in a functional programming language. They encapsulate computations with side effects in a way that allows them to be composed and sequenced in a pure, functional manner.

How would you use pattern matching in Frege?

Pattern matching in Frege is used to check the structure of data and extract values from it. It's done using the 'case' keyword, followed by the expression to match, and a series of patterns and corresponding results.

Describe the difference between 'let' and 'where' in Frege.

'Let' and 'where' are both used to define local bindings in Frege, but they differ in their scope. 'Let' bindings are expressions that can be used anywhere, while 'where' bindings are only visible to the function they are defined in.

What are type classes in Frege, and how would you use them?

Type classes in Frege provide a way to define behavior that can be shared across multiple types. You can define a type class with the 'class' keyword, and then define functions that work on any type that is an instance of that class.

How would you handle exceptions in Frege?

Frege has a 'try' expression for handling exceptions. It allows you to catch and handle exceptions in a controlled manner.

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A skilled Frege engineer should demonstrate a strong understanding of functional programming, problem-solving skills, and experience with Haskell or similar questions. Red flags include lack of detail in responses, inability to explain complex concepts simply, or unfamiliarity with Frege's unique features.

Digging deeper

Code questions

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

What does the following simple Frege code do?main _ = println 'Hello, World!'
This code prints the string 'Hello, World!' to the console.
What does the following Frege code do?add x y = x + y
main args = println (add 5 6)
This code defines a function 'add' that adds two numbers together. It then calls this function with the arguments 5 and 6, and prints the result to the console.
What does the following Frege code do?main args = println (map (*2) [1,2,3,4,5])
This code maps the function (*2) over the list [1,2,3,4,5], effectively doubling each element in the list. The result is printed to the console.
What does the following Frege code do?main args = do
  forkIO (println 'Hello from a thread!')
  println 'Hello from the main thread!'
This code creates a new thread that prints 'Hello from a thread!' to the console. It then prints 'Hello from the main thread!' from the main thread.
What does the following Frege code do?data Person = Person String Int
main args = let p = Person 'Alice' 25 in println p
This code defines a data type 'Person' with two fields: a String and an Int. It then creates an instance of 'Person', 'Alice' aged 25, and prints this instance to the console.
What does the following advanced Frege code do?data Tree a = Empty | Node a (Tree a) (Tree a)
main args = let t = Node 1 (Node 2 Empty Empty) (Node 3 Empty Empty) in println t
This code defines a generic binary tree data type with 'Empty' leaves and 'Node' elements. It then creates a binary tree with elements 1, 2, and 3, and prints this tree to the console.

Wrap-up questions

Final candidate for Frege role questions

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

How would you implement concurrency in Frege?

Frege has support for concurrent programming through the use of 'IO' actions and the 'forkIO' function. You can create a new thread of execution by passing an 'IO' action to 'forkIO'. This allows you to perform multiple computations concurrently.

Describe the difference between 'IO' and 'ST' monads in Frege.

'IO' and 'ST' are both monads used for handling side effects in Frege. The 'IO' monad is used for input/output operations, while the 'ST' monad is used for mutable state. The key difference is that 'IO' operations can have global side effects, while 'ST' operations are guaranteed to be local to the function they are used in.

What are Higher-Order Functions in Frege?

Higher-Order Functions in Frege are functions that can take other functions as arguments or return functions as results. They are a key feature of functional programming and are used extensively in Frege.

How would you create and use a custom type class in Frege?

You can create a custom type class in Frege using the 'class' keyword, followed by the name of the class and its type variable. You can then declare any functions that should be part of this class. To use this class, you declare a type as an instance of the class and implement the required functions.

Describe the difference between 'pure' and 'impure' functions in Frege.

Pure functions in Frege are functions that do not have any side effects. They always produce the same output for the same input. Impure functions, on the other hand, can have side effects and their output can vary for the same input.

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Frege application related

Product Perfect's Frege development capabilities

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

Frege Consultive assessments

Frege Application Conversion Assessment Frege Application Integration Assessment Frege Data & Database Integration Assessment

Custom Frege development projects

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

Frege Developer Hiring Guide

Hiring Guide for Frege Engineers

First 20 minutes

General Frege knowledge and experience

What are Algebraic Data Types in Frege?

How would you define a function in Frege?

Describe the difference between Lazy and Strict evaluation in Frege.

What are the basic data types in Frege?

How would you describe Frege's type inference?

What youre looking for early-on

Does the candidate have a good understanding of how to test and debug Frege code?

Has the candidate shown the ability to write clean and maintainable code?

Does the candidate have experience with functional programming paradigms?

Can the candidate effectively work with Frege's type system?

Has the candidate demonstrated problem-solving abilities?

Does the candidate possess a sound understanding of Frege's syntax and semantics?

Next 20 minutes

Specific Frege development questions

What are Monads in Frege, and how would you use them?

How would you use pattern matching in Frege?

Describe the difference between 'let' and 'where' in Frege.

What are type classes in Frege, and how would you use them?

How would you handle exceptions in Frege?

The ideal back-end app developer

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

What does the following simple Frege code do?

This code prints the string 'Hello, World!' to the console.

What does the following Frege code do?

This code defines a function 'add' that adds two numbers together. It then calls this function with the arguments 5 and 6, and prints the result to the console.

What does the following Frege code do?

This code maps the function (*2) over the list [1,2,3,4,5], effectively doubling each element in the list. The result is printed to the console.

What does the following Frege code do?

This code creates a new thread that prints 'Hello from a thread!' to the console. It then prints 'Hello from the main thread!' from the main thread.

What does the following Frege code do?

This code defines a data type 'Person' with two fields: a String and an Int. It then creates an instance of 'Person', 'Alice' aged 25, and prints this instance to the console.

What does the following advanced Frege code do?

This code defines a generic binary tree data type with 'Empty' leaves and 'Node' elements. It then creates a binary tree with elements 1, 2, and 3, and prints this tree to the console.

Wrap-up questions

Final candidate for Frege role questions

How would you implement concurrency in Frege?

Describe the difference between 'IO' and 'ST' monads in Frege.

What are Higher-Order Functions in Frege?

How would you create and use a custom type class in Frege?

Describe the difference between 'pure' and 'impure' functions in Frege.

Frege Consultive assessments

Custom Frege development projects