Hiring guide for Befunge Engineers

Befunge Developer Hiring Guide

Befunge is a stack-based, reflective, esoteric programming language developed by Chris Pressey in 1993. It is unique for its two-dimensional toroidal grid structure, which allows the control flow to move in four directions: left, right, up and down. The language was designed as a challenge to traditional compiler theory and features self-modifying code. Befunge's unusual approach has made it popular for programming contests and academic study of unconventional computing models. Its original implementation and subsequent versions are available on the author's website and GitHub repository.

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

First 20 minutes

General Befunge app knowledge and experience

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

How would you explain the concept of stack in Befunge?
In Befunge, a stack is a data structure that follows the Last-In-First-Out (LIFO) principle. It's used to store and retrieve data, where the most recently stored data is the first to be retrieved.
What are the core principles of Befunge programming language?
Befunge is a two-dimensional, stack-based, reflective esolang. It's designed to be as difficult to compile as possible. The core principles include multidimensionality, unpredictability, and interactivity.
Describe the difference between Befunge-93 and Befunge-98.
Befunge-93 is the original version with a fixed playfield size of 80x25 and only one stack. Befunge-98 is an extension with multiple stacks, self-modifying code, and a playfield of arbitrary size.
How would you handle errors in Befunge?
Handling errors in Befunge is tricky due to its esoteric nature. However, one can use the 'g' instruction to get a value from the playfield and check if it's expected before proceeding.
What are the uses of the 'p' and 'g' commands in Befunge?
'p' and 'g' commands are used for self-modifying code. 'p' puts a value onto the playfield, while 'g' gets a value from the playfield.
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What you’re looking for early on

Does the candidate have a strong understanding of Befunge?
Can the candidate demonstrate problem-solving skills?
Is the candidate able to explain their thought process clearly?
Does the candidate show an ability to learn and adapt?

Next 20 minutes

Specific Befunge 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 '@' and '#' commands in Befunge.
'@' command ends the program while '#' command is a bridge that makes the instruction pointer skip the next cell.
How would you implement a loop in Befunge?
Loops in Befunge are created using the '<', '>', '^', and 'v' commands to direct the instruction pointer, along with conditional statements like '_' and '|'.
What are the uses of '_' and '|' commands in Befunge?
'_' and '|' are conditional commands. '_' pops a value and moves right if it's zero, left otherwise. '|' pops a value and moves down if it's zero, up otherwise.
How would you debug a Befunge program?
Debugging Befunge is challenging due to its esoteric nature. However, one can use the '?' command to randomly change the direction of the instruction pointer for testing purposes.
Describe the difference between ':', ';', and '$' commands in Befunge.
':' duplicates the top stack value, ';' starts and ends a comment, and '$' pops and discards the top stack value.
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The ideal back-end app developer

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

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

What does this simple Befunge code do?
 ^  <  @
This is a simple Befunge code for a decrementing counter. It gets the value at position (0,0), subtracts 1 from it, and puts it back. If the result is not zero, it loops back and repeats the process. If the result is zero, it ends the program.
What does this Befunge code do that includes a '#' character?
 ^  <  @
This Befunge code, with the '#' character, is a simple example of a bridge. The '#' character in Befunge is a bridge, which causes the instruction pointer to skip the next cell in the current direction of the instruction pointer. In this case, it skips over the 'v' character and continues executing to the right.
What will be the output of this Befunge code that manipulates a stack?
This Befunge code pushes the numbers 1, 2, 3, 4, 5 onto the stack, then the '$' command pops and discards the top value from the stack, and finally, the '@' command ends the program. So, the final state of the stack will be [1, 2, 3, 4].
What does this Befunge code do that uses the 'p' and 'g' commands?
This Befunge code demonstrates the use of the 'p' and 'g' commands, which are used for storing and retrieving values in the playfield. The 'p' command pops y, x, and v, then changes the character at (x,y) to the character with ASCII value v. The 'g' command pops y and x, then pushes the ASCII value of the character at that position. In this case, the code stores 1 at position (0,0) and retrieves it immediately, then outputs it.

Wrap-up questions

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

How would you implement recursion in Befunge?
Recursion in Befunge can be implemented using the 'r' command, which reflects the instruction pointer, effectively creating a loop until a base case is met.
What are the uses of '!', '`', and '~' commands in Befunge?
'!' is a logical NOT, '`' is a greater-than comparison, and '~' reads a character from input.
Describe the difference between '0'-'9' and 'a'-'f' commands in Befunge.
'0'-'9' push corresponding decimal numbers onto the stack, while 'a'-'f' push hexadecimal values from 10 to 15.

Befunge application related

Product Perfect's Befunge development capabilities

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