In this section, we will write our first MUMPS program: the classic "Hello, World!" example. This simple program will help you understand the basic syntax and structure of MUMPS.

1. Basic Syntax: Understanding the basic structure of a MUMPS program.
2. Writing a Program: How to write and execute a simple MUMPS program.
3. Output: Using the WRITE command to display text.

1. Open Your MUMPS Environment: Ensure that your MUMPS environment is set up and running. You should have access to a MUMPS interpreter or an integrated development environment (IDE) that supports MUMPS.

2. Create a New Routine: In MUMPS, programs are often referred to as routines. Create a new routine file named HELLO.m.

3. Write the Code: Enter the following code into your routine file:

   HELLO ; This is a comment
   WRITE "Hello, World!", !
   QUIT
   

   Let's break down this code:

   • HELLO: This is the label for the routine. Labels in MUMPS are used to identify different parts of the code.
   • ; This is a comment: Comments in MUMPS start with a semicolon (;). They are ignored by the interpreter and are used to explain the code.
   • WRITE "Hello, World!", !: The WRITE command outputs text to the screen. The ! at the end of the line is a carriage return, which moves the cursor to the next line.
   • QUIT: This command terminates the routine.

4. Save the File: Save your routine file with the .m extension.

1. Load the Routine: In your MUMPS environment, load the routine by typing the following command:

   ZLOAD "HELLO.m"
   

2. Execute the Routine: Run the routine by typing the following command:

   DO ^HELLO
   

   You should see the output:

   Hello, World!
   

Here is a complete example of the "Hello, World!" program in MUMPS:

• Missing QUIT Statement: Ensure you include the QUIT statement to properly terminate the routine.
• Syntax Errors: Double-check your syntax, especially the use of quotes and punctuation.
• Environment Setup: Make sure your MUMPS environment is correctly set up and that you have the necessary permissions to create and execute routines.

Modify the "Hello, World!" program to display your name instead of "World".

Solution:

Extend the program to display an additional line of text, such as "Welcome to MUMPS programming!".

Solution:

In this section, you learned how to write and execute a simple "Hello, World!" program in MUMPS. You now understand the basic syntax and structure of a MUMPS routine, how to use the WRITE command for output, and how to run your program in the MUMPS environment. This foundational knowledge will be essential as you progress through more complex topics in MUMPS programming.