Procedures

This topic is meant to document procedures in Pile

Overview

In the Pile programming language, a procedure is a reusable block of code designed to perform specific tasks. Unlike traditional functions in other languages, procedures in Pile:

  • Do not have named arguments: Data is passed and manipulated solely via the stack.
  • Do not return values: The stack holds all the intermediate and final results of the operations performed.
  • Procedures are a key part of writing modular and maintainable code in Pile, allowing you to define, organize, and reuse blocks of code.

Defining a Procedure

To define a procedure in Pile, use the proc keyword followed by the name of the procedure and the end keyword to mark the end of the procedure.

Syntax:

proc <NAME>
  <CODE>
end

Code examples

Here's an example demonstrating a simple procedure to add two numbers:

proc add_three_numbers
  + +
end

5 5 5 add_three_numbers println
# Output: 15

Here's another example showing how procedures can interact with the stack for more complex operations:

proc square
  dup *
end

8 square println
# Output: 64

This procedure is meant to check if a given number is even or odd:

proc even_odd
  2 swap % 0 = if
    "Even" println
  else
    "Odd" println
  end
end

4 even_odd # Output: Even
7 even_odd # Output: Odd

Notice how the parameters (values on the stack) are manipulated within the procedure and the results remain on the stack after execution.

Back to top