# Comment

Comment is part of computer code that doesn't affect how the code is interpreted by the computer and is intended to hold information for humans (even though comments can sometimes contain additional information for computers such as metadata and autodocumentation information). There are comments in basically all [programming languages](programming_language.md), they usually start with `//`, `#`, `/*` and similar symbols.

**You should comment you source code.** General tips on commenting:

- ALWAYS put a **global file comment** at the top of a file to make it [self-contained](self_contained.md). It should include:
  - **Description of what the file actually does.** This is extremely important for [readability](readability.md), documentation and quick orientation. If a new programmer comes looking for a specific part of the code, he may waste hours on searching the wrong files just because the idiotic author couldn't be bothered to include fucking three sentences at the start of the file. [Modern](modern.md) program just don't fucking do this anymore, this is just [shit](shit.md).
  - [License](license.md)/[waiver](waiver.md), either full text or link. Even if your repo contains a global license (which it should), it's good for the file to carry the license because the file may just be copy pasted on its own into some other project and then it will appear as having no license.
  - **Name/nick of the author(s)** and roughly the date of creation (year is enough). This firstly helps legally assess [copyright](copyright.md) (who and for how long holds the copyright) and secondly helps others contact the author in case of encountering something weird in the code.
- Comment specific blocks of code with **keywords** -- this will help searching the code with tools like [grep](grep.md). E.g. in game's code add comment `// player: shoot, fire` to the part of code that handles player's shooting so that someone searching for any one of these two words will be directed here.
- All functions (maybe with exceptions of trivial one-liners) should come with a comment documenting:
  - **Behavior** of the function, what it does and also how it does that (Is the function slow? Is it safe? Does it perform checks of arguments? Does it have [side effects](side_effect.md)? ...).
  - **Meaning of all arguments** and if needed their possible values.
  - **Return value meaning**.
- You may decide to use comment format of some [autodoc](autodoc.md) system such as [doxygen](doxygen.md) -- it costs nothing and helps firstly unify the style of your comments and secondly, obviously, generate automatic documentation of your code, as well as possibly automatically process it in other ways.
- TODO: moar