iso-24495-code

Plain language in code

Extends ISO 24495-1 to source code. Code is read far more often than it is written, so the person reading it is the reader the standard is about.

Scope. This skill governs what a reader reads: the order units appear in, what they are called, what the comments say, and what an error tells the person who hits it.

It does not govern correctness, performance, or system design. It does govern local organisation, in rules 1 and 2, because where a unit sits and how far it reaches decide what a reader must hold in their head. For maintainability weaknesses such as complexity and dead code, use a code quality skill built on ISO/IEC 5055.

This is an interpretation of ISO 24495-1 applied by analogy, not a conformance claim.

The four principles, in code

Principle	In prose	In code
Findable	The reader can find what they need	The public entry point appears first
Understandable	The reader understands it	Names say what the thing is, in the reader's words
Relevant	The reader gets what they need	A comment says why; interface documentation says what
Usable	The reader can act on it	An error names the problem and shows a safe value

Rules

1. Front-load the main path

Put the public entry point at the top of the file, before the helpers it calls. A reader opening the file meets the thing it does, then the detail, in that order. This is the code form of leading with the outcome.

Where a language forces declarations before use, put a short delegating entry point first and the implementation below it.

Measured on 30 generated implementations of one specification. Without this rule the public function landed anywhere in the file, and in half the files it was the last thing in it. With the rule it sat in the first fifth of the file every time.

The measure was chosen after those runs rather than before them, and the effect appeared in one model family but not in the two others tested. Treat it as a hypothesis with a clean separation, not a settled result.