Product Perfect

**CLU** is a general-purpose programming language designed by **Barbara Liskov** and **Alan Snyder** at **MIT** in the early 1970s. It was one of the first languages to support object-oriented programming, and its design influenced many later languages, including **C++, Java**, and **Python**. CLU was originally implemented on the **PDP-10** computer, and later ported to other platforms. It is no longer in active development, but there are still a number of CLU implementations available online. **Sources:** * [CLU Language Reference Manual](https://pdos.csail.mit.edu/archive/rhapsody/manuals/clurav2.pdf) * [CLU at Wikipedia](https://en.wikipedia.org/wiki/CLU_(programming_language))

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

First 20 minutes

General CLU app knowledge and experience

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

How would you define a CLU data type?

In CLU, a data type is defined using a cluster, which includes the type representation and a set of operations.

What are the fundamental data types in CLU?

The fundamental data types in CLU are integer, real, boolean, character, and string.

Describe the difference between a procedure and a coroutine in CLU.

A procedure is a sequence of instructions that perform a specific task and then return to the caller. A coroutine, on the other hand, can suspend its execution and transfer control to other coroutines and resume from where it left off.

How would you create an exception in CLU?

In CLU, you can create an exception using the signal operation. For example, signal failure('message') would create an exception with a failure tag and a message.

What is a cluster in CLU and what is its purpose?

A cluster in CLU is a module that encapsulates a data type and its operations. The purpose of a cluster is to provide data abstraction.

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What you’re looking for early on

Does the candidate exhibit a strong understanding of the CLU programming language?

Can the candidate demonstrate problem-solving skills?

Has the candidate worked on any projects using CLU before?

Does the candidate seem to work well under pressure?

Next 20 minutes

Specific CLU 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 handle an exception in CLU?

In CLU, exceptions are handled using the except clause in the procedure definition. For example, except failure(s: string) would handle a failure exception and bind the message to the variable s.

What are the iteration constructs available in CLU?

CLU provides three iteration constructs: for, while, and until. The for construct is used for definite iteration, while the while and until constructs are used for indefinite iteration.

Describe the difference between a yield and a return statement in CLU.

A yield statement is used in a coroutine to provide a result and suspend execution, while a return statement is used in a procedure to provide a result and terminate execution.

How would you create a generic data type in CLU?

In CLU, you can create a generic data type using the own statement in a cluster. For example, own count: int would create a generic integer data type named count.

What is the purpose of a separator in CLU?

A separator in CLU is used to separate the arguments in a procedure call or a cluster invocation. It is denoted by the dollar symbol ($).

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

What does this simple CLU code do?
proc print_hello_world =
    begin
        print("Hello, World!")
    end print_hello_world
This code defines a procedure named 'print_hello_world' that prints out the string 'Hello, World!' when called.
What does this CLU code do with the 'signal' keyword?
proc divide(x: int, y: int) returns (int, int)
    signals (zero_division)
    where
        y = 0, signal zero_division
    end
    return(x/y, x mod y)
end divide
This code defines a procedure named 'divide' that takes two integers as arguments. If the second argument is zero, it signals a 'zero_division' error. Otherwise, it returns the quotient and remainder of the division.
What does this CLU code do with the 'array' data structure?
arr = array.new(10)
for i: int in int$from_to(1, 10) do
    array.put(arr, i, i*i)
end
This code creates a new array of size 10 and populates it with the squares of the numbers from 1 to 10. The index of each element in the array is its square root.
What does this CLU code do with the 'thread' keyword?
thread
    for i: int in int$from_to(1, 10) do
        print(i)
    end
end
This code creates a new thread that prints the numbers from 1 to 10. The 'thread' keyword in CLU is used to create concurrent processes.

Wrap-up questions

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

Describe the difference between a cluster and a coroutine in CLU.

A cluster in CLU is a module that encapsulates a data type and its operations, while a coroutine is a control structure that allows multiple entry points for suspending and resuming execution.

How would you implement polymorphism in CLU?

In CLU, polymorphism can be implemented using variant records and the typecase statement, which allows different behaviors depending on the type of the data.

What are the mechanisms for concurrency in CLU?

CLU provides two mechanisms for concurrency: coroutines and processes. Coroutines allow cooperative multitasking, while processes allow preemptive multitasking.

CLU application related

Product Perfect's CLU development capabilities

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

CLU Consultive assessments

CLU Application Conversion Assessment CLU Application Integration Assessment CLU Data & Database Integration Assessment

Custom CLU development projects

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

Hiring guide for CLU Engineers

CLU Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

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

CLU Consultive assessments

Custom CLU development projects