Proposal for new "Commenting" wiki text (was: [RFC] Deciding on style for multi-line comments)
Hi folks,
I think we kind of agreed that the wiki text about "Commenting" should change. So here is my proposal, feel free to edit, add something or just ack or complain about it.
== Commenting ==
Comments are good, but there is also a danger of over-commenting. NEVER try to explain HOW your code works in a comment: it's much better to write the code so that the _working_ is obvious, and it's a waste of time to explain badly written code.
Generally, you want your comments to tell WHAT your code does, not HOW. Also, try to avoid complex comments inside a function body: if the function is so complex that you need to separately comment parts of it, you should probably go back to chapter 6 for a while. You can make small comments to note or warn about something particularly clever (or ugly), but try to avoid excess. Instead, put the comments at the head of the function, telling people what it does, and possibly WHY it does it.
coreboot style for comments is the C89 "/* ... */" style. You may also use C99-style "// ..." comments.
The preferred style for concise multi-line comments that explain a single piece of code is:
/* This is the preferred style for shorter multi-line comments that avoids excessive blank lines. */
Note that there shouldn't be leading asterisks on new lines in the concise style.
The preferred style for long multi-line comments is:
/* * This is the preferred style for multi-line * comments in the coreboot source code. * * Description: A column of asterisks on the left side, * with beginning and ending almost-blank lines. */
Some rules of thumb to decide which style to use:
- If you are commenting a whole function (indentation level 0) or something high level (indentation level 1), use the long style.
- If you want to explain a single piece of code and your comment doesn't span multiple paragraphs, use the concise style.
- Otherwise you might want to ask yourself why what you're going to explain doesn't deserve an own function.
It's also important to comment data, whether they are basic types or derived types. To this end, use just one data declaration per line (no commas for multiple data declarations). This leaves you room for a small comment on each item, explaining its use.
In case of doubt, the author of the code shall have the last word on comment styles. He should know best which style makes his code most readable.
Nico
Hey Nico, Thanks for writing that up and not just letting this drop with no resolution and action.
To anyone just coming in on the discussion, here's what we're talking about changing: https://www.coreboot.org/Coding_Style#Commenting
I'd suggest just a couple of changes to your update:
Let's define what a "short" comment is to avoid future arguments that 10 lines is short:
/* This is the preferred style for two or three line comments that avoids excessive blank lines. */
And I'm not certain of this paragraph, and I'd recommend removing or changing it a bit.
In case of doubt, the author of the code shall have the last word on comment styles. He should know best which style makes his code most readable.
1) I think that Stefan as the project leader should have the decision about anything that is controversial enough to need a last word. 2) What if the author is female? :) Maybe use 'they' as the pronoun if this paragraph is left in. Not a big deal, but I'd like to be inclusive. 3) I think this might be just asking for arguments. I'm not talking about anyone specific, just thinking of discussions in the past. -- "As the author I LIKE ascii art in my comments and I get the final say." -- We're going to get lawyer arguments: "It says above that the c99 style is valid - why can't we just prefix the whole 16 line block with '//'"? -- "I know it says not to say 'increment i', but as the author, I think it's helpful." 4) I think this would be the only "the author has the final say" policy - what happens when someone rewrites the comment in a following patch? Who is the author?
Maybe we could change it from "has the last word" to something saying like:
If the author has reasonable arguments for breaking the recommended style guide to improve readability, others should be respectful of those differences.
I think this preserves the intent without some of the issues.
Martin
On Sun, Sep 4, 2016 at 8:42 AM, Nico Huber nico.h@gmx.de wrote:
Hi folks,
I think we kind of agreed that the wiki text about "Commenting" should change. So here is my proposal, feel free to edit, add something or just ack or complain about it.
== Commenting ==
Comments are good, but there is also a danger of over-commenting. NEVER try to explain HOW your code works in a comment: it's much better to write the code so that the _working_ is obvious, and it's a waste of time to explain badly written code.
Generally, you want your comments to tell WHAT your code does, not HOW. Also, try to avoid complex comments inside a function body: if the function is so complex that you need to separately comment parts of it, you should probably go back to chapter 6 for a while. You can make small comments to note or warn about something particularly clever (or ugly), but try to avoid excess. Instead, put the comments at the head of the function, telling people what it does, and possibly WHY it does it.
coreboot style for comments is the C89 "/* ... */" style. You may also use C99-style "// ..." comments.
The preferred style for concise multi-line comments that explain a single piece of code is:
/* This is the preferred style for shorter multi-line comments that avoids excessive blank lines. */Note that there shouldn't be leading asterisks on new lines in the concise style.
The preferred style for long multi-line comments is:
/* * This is the preferred style for multi-line * comments in the coreboot source code. * * Description: A column of asterisks on the left side, * with beginning and ending almost-blank lines. */Some rules of thumb to decide which style to use:
- If you are commenting a whole function (indentation level 0) or something high level (indentation level 1), use the long style.
- If you want to explain a single piece of code and your comment doesn't span multiple paragraphs, use the concise style.
- Otherwise you might want to ask yourself why what you're going to explain doesn't deserve an own function.
It's also important to comment data, whether they are basic types or derived types. To this end, use just one data declaration per line (no commas for multiple data declarations). This leaves you room for a small comment on each item, explaining its use.
In case of doubt, the author of the code shall have the last word on comment styles. He should know best which style makes his code most readable.
Nico
On Sun, Sep 4, 2016 at 7:42 AM, Nico Huber nico.h@gmx.de wrote:
Hi folks,
I think we kind of agreed that the wiki text about "Commenting" should change. So here is my proposal, feel free to edit, add something or just ack or complain about it.
== Commenting ==
Comments are good, but there is also a danger of over-commenting. NEVER try to explain HOW your code works in a comment: it's much better to write the code so that the _working_ is obvious, and it's a waste of time to explain badly written code.
Generally, you want your comments to tell WHAT your code does, not HOW. Also, try to avoid complex comments inside a function body: if the function is so complex that you need to separately comment parts of it, you should probably go back to chapter 6 for a while. You can make small comments to note or warn about something particularly clever (or ugly), but try to avoid excess. Instead, put the comments at the head of the function, telling people what it does, and possibly WHY it does it.
coreboot style for comments is the C89 "/* ... */" style. You may also use C99-style "// ..." comments.
The preferred style for concise multi-line comments that explain a single piece of code is:
/* This is the preferred style for shorter multi-line comments that avoids excessive blank lines. */
why does the concise style have to be so different from the verbose style? Lines starting with '* ' are easier identifiable as comments.
--vb
Note that there shouldn't be leading asterisks on new lines in the concise style.
The preferred style for long multi-line comments is:
/* * This is the preferred style for multi-line * comments in the coreboot source code. * * Description: A column of asterisks on the left side, * with beginning and ending almost-blank lines. */Some rules of thumb to decide which style to use:
- If you are commenting a whole function (indentation level 0) or something high level (indentation level 1), use the long style.
- If you want to explain a single piece of code and your comment doesn't span multiple paragraphs, use the concise style.
- Otherwise you might want to ask yourself why what you're going to explain doesn't deserve an own function.
It's also important to comment data, whether they are basic types or derived types. To this end, use just one data declaration per line (no commas for multiple data declarations). This leaves you room for a small comment on each item, explaining its use.
In case of doubt, the author of the code shall have the last word on comment styles. He should know best which style makes his code most readable.
Nico
Dear Nico,
Thank you for sending the proposal around.
What ever is decided on, please make sure it can be automatically checked by the commit hooks, and that the scripts are updated in the repository at the same time the guidelines are changed.
Thanks,
Paul
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Martin Roth -
Nico Huber -
Paul Menzel -
Vadim Bendebury