Concept: Functions and Code Blocks

Concept: Functions and Code Blocks#

Functions and Decorators#

In the last chapter, we saw code like this:

@world.register
def on_setup(self):
    world.fps = 1
    world.speed = 3

  • In the second line, a function is defined that performs specific instructions (we’ll discuss that more below).

  • In the first line, a decorator is used. This decorator attaches the function to the world object. Whenever the system wants to call world.on_setup, the function you defined is executed instead. This way, you can define functions that respond to various events, like key presses, actor collisions, etc.

Indentation and Code Blocks#

Lines 3 and 4 in the example above are indented. This means they belong to the function and are executed when it is called.

In Python, indentation is used to define code blocks — that is, when a conditional or function begins and ends. All lines with the same level of indentation are considered part of the same block.

Coding Standards — How Much Should You Indent?#

The Python language doesn’t enforce how many spaces to use for indentation — whether 3, 4, or 5 spaces — but all lines in a block must be indented equally.

However, Python developers have agreed on certain coding standards so that code looks consistent across projects.

  • The commonly accepted rule is to indent code using 4 spaces.

  • While you can use your own style, it is strongly recommended to follow this standard, especially when working in teams.

Python’s functions and conventions are documented in official proposals called PEPs (Python Enhancement Proposals). Style recommendations can be found in PEP 8.

Besides indentation, it covers many other topics — for example:

a = a + 3  # Recommended

instead of:

a=a+3  # Less readable

Although Python doesn’t enforce these rules, following them helps make your code easier for others to read.

Helpful Tools#

Most modern code editors support:

  • Auto-formatting (e.g., automatic indentation)

  • Linting (checking your code for style issues)

These tools help you write clean and readable code more easily.

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