Hiring guide for REXX Engineers

REXX Developer Hiring Guide

REXX (Restructured Extended Executor) is an interpreted programming language developed by IBM. It was designed to be a scripting language with easy readability and usability, making it ideal for both beginners and experienced programmers. REXX supports different data types including strings, numbers, and words, which makes it versatile for various applications. It is often used in command macros for IBM mainframe operating systems but can also be found in other computing environments. The language offers robust error handling capabilities and built-in debugging features as well.

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

First 20 minutes

General REXX app knowledge and experience

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

How would you define REXX?
REXX is a high-level programming language that was designed to be both easy to learn and easy to read. It is an interpreted language, which means that it can be run directly from the source code, without the need for compilation.
What are the key features of REXX?
REXX has several key features, including its simplicity and ease of use, its ability to be used for both scripting and general-purpose programming, and its extensive support for string handling and data parsing.
Describe the difference between REXX and other scripting languages.
REXX is different from other scripting languages in several ways. It is more human-readable than most, it has a very simple syntax, and it is designed to be easy to learn and use. Additionally, REXX has extensive support for string handling and data parsing, which are not as robust in many other scripting languages.
How would you use REXX to automate a task?
To automate a task with REXX, you would write a script that outlines the steps of the task, then run the script. The script could include commands to interact with the operating system, manipulate data, or interact with other programs.
What are the data types supported by REXX?
REXX primarily deals with strings. It does not have specific data types like integer, float, or boolean. All data are treated as strings and can be manipulated as such.
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What you’re looking for early on

Does the candidate have a solid understanding of REXX language?
Has the candidate demonstrated problem-solving abilities?
Did the candidate mention any experience with IBM mainframe systems?
Has the candidate shown good communication skills during the interview?

Next 20 minutes

Specific REXX 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 a REXX function and a REXX subroutine.
A REXX function is a reusable piece of code that performs a specific task and returns a value. A REXX subroutine, on the other hand, is a reusable piece of code that performs a specific task but does not return a value.
How would you handle errors in a REXX program?
REXX provides several ways to handle errors. One way is to use the SIGNAL ON ERROR command to direct the program to a specific label if an error occurs. Another way is to use the condition() function to check for specific error conditions and handle them accordingly.
What are the different ways to run a REXX script?
There are several ways to run a REXX script. You can run it directly from the command line, you can call it from another REXX script, or you can set it up to run automatically at a specific time or when a specific event occurs.
Describe the difference between the INTERPRET and EVALUATE statements in REXX.
The INTERPRET statement in REXX allows you to execute a string as a REXX statement, while the EVALUATE statement allows you to evaluate a string as an expression and return the result.
How would you use the PARSE instruction in REXX?
The PARSE instruction in REXX is used to split a string into separate pieces based on a specified pattern. You can use it to extract specific pieces of information from a string, or to split a string into an array of substrings.
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The ideal back-end app developer

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

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

What does the following REXX code do?
say 'Hello, World!'
The code prints the string 'Hello, World!' to the standard output.
What will be the output of the following REXX code?
x = 5
y = 10
say x + y
The code will output the sum of the variables x and y, which is 15.
What does the following REXX code do?
do i = 1 to 5
say 'Number:' i
The code prints the numbers from 1 to 5, each prefixed by the string 'Number:'.
What does the following REXX code do?
call on halt
say 'Program started'
say 'Program ended'
The code sets up a condition trap for the halt condition. When the exit instruction is executed, the program ends without printing 'Program ended'.

Wrap-up questions

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

What are the different types of variables in REXX?
REXX has two types of variables: simple variables and compound variables. Simple variables hold a single value, while compound variables can hold multiple values in a structured format.
Describe the difference between the DO WHILE and DO UNTIL loops in REXX.
The DO WHILE loop in REXX continues to execute as long as the specified condition is true, while the DO UNTIL loop continues to execute until the specified condition becomes true.
How would you use the SAY instruction in REXX?
The SAY instruction in REXX is used to output a string to the console. You can use it to display messages, output the values of variables, or print the results of calculations.

REXX application related

Product Perfect's REXX development capabilities

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