Hiring guide for ELisp# Engineers

ELisp# Developer Hiring Guide

ELisp#, also known as Emacs Lisp, is a contemporary and sophisticated dialect of the Lisp programming language. It is predominantly utilized for extending the functionality of the GNU Emacs text editor, which is renowned for its customizability and extensibility. The inception of ELisp# can be traced back to the 1980s, a testament to its robustness and adaptability. Incorporating the latest advancements in programming paradigms, ELisp# has evolved into a modernized language that supports a wide array of features such as dynamic scoping and lexical binding. These characteristics allow for an enhanced level of flexibility in variable declarations and usage, thereby facilitating more efficient coding practices. ELisp# distinguishes itself through its seamless integration with the Emacs environment. This integration enables real-time execution of code within the editor, providing developers with immediate feedback and significantly reducing debugging time. Moreover, it allows for direct

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

First 20 minutes

General ELisp# app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in ELisp# 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 ELisp#?
The basic data types in ELisp# include integers, floats, strings, lists, vectors, symbols, hash-tables, and functions.
How would you define a variable in ELisp#?
You can define a variable using the `setq` or `defvar` command. For example, `(setq x 10)` or `(defvar x 10)`.
How would you define a function in ELisp#?
You can define a function using the `defun` command. For example, `(defun my-function (x) (+ x x))`.
What is the purpose of the `car` and `cdr` functions in ELisp#?
`car` and `cdr` are used for accessing the elements of a list. `car` returns the first element of a list, and `cdr` returns the rest of the list.
What is the purpose of the `cons` function in ELisp#?
`cons` is used to construct a new list by prepending an element to an existing list. For example, `(cons 1 '(2 3))` returns `(1 2 3)`.
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What you’re looking for early on

Does the candidate have a strong understanding of ELisp#?
How well does the candidate understand and apply object-oriented programming principles?
Can the candidate solve complex problems using ELisp#?
Does the candidate have experience with version control systems like Git?

Next 20 minutes

Specific ELisp# 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 the control flow structures in ELisp#?
Control flow structures in ELisp# include `if`, `cond`, `when`, `unless`, `while`, `dolist`, and `dotimes`.
How would you handle errors in ELisp#?
Errors can be handled using the `condition-case` construct, which allows you to catch and handle exceptions.
What is the difference between `eq`, `eql`, `equal`, and `equalp` in ELisp#?
`eq` tests for identity, `eql` tests for equality of value and type, `equal` tests for structural equality, and `equalp` tests for equality ignoring type differences.
How would you write a recursive function in ELisp#?
A recursive function can be written using `defun` and calling the function within its own body. For example, a function to compute the factorial of a number could be written as `(defun factorial (n) (if (<= n 1) 1 (* n (factorial (- n 1)))))`.
How would you use a lambda function in ELisp#?
A lambda function can be defined using the `lambda` keyword. For example, `(lambda (x) (* x x))` defines a function that squares its argument.
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The ideal back-end app developer

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

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

What does this simple ELisp# code do?
(defun hello-world () (print "Hello, World!")) (hello-world)
This code defines a function named 'hello-world' that prints the string 'Hello, World!' when called. The function is then called, so 'Hello, World!' will be printed.
What will be the output of this ELisp# code?
(let ((x 10) (y 20)) (+ x y))
This code declares two variables 'x' and 'y' with values 10 and 20 respectively, and then adds them. The output will be 30.
What does this ELisp# code do with the list?
(setq my-list '(1 2 3 4 5)) (mapcar (lambda (x) (* x x)) my-list)
This code first sets a variable 'my-list' to a list of numbers from 1 to 5. Then it uses 'mapcar' to apply a lambda function to each element of the list. The lambda function squares each element. The result will be a new list '(1 4 9 16 25)'.
What does this ELisp# code do related to threading?
(make-thread (lambda () (sleep-for 5) (print "Hello, World!")))
This code creates a new thread that sleeps for 5 seconds and then prints 'Hello, World!'. The 'make-thread' function is used to create a new thread in ELisp#.

Wrap-up questions

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

What are macros in ELisp# and how would you define one?
Macros in ELisp# are a way to define reusable code snippets. They are defined using the `defmacro` command. For example, `(defmacro inc (var) `(setq ,var (+ ,var 1)))` defines a macro that increments a variable.
How would you use the `mapcar` function in ELisp#?
`mapcar` applies a function to each element of a list and returns a list of the results. For example, `(mapcar 'square '(1 2 3 4))` returns `(1 4 9 16)`.
Describe the difference between lexical and dynamic scoping in ELisp#.
In lexical scoping, variables are resolved in the context where they were defined. In dynamic scoping, variables are resolved in the context where they are used.

ELisp# application related

Product Perfect's ELisp# development capabilities

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