[RFC] Coding guidelines - Comma on left

[drathbun]

Regarding comma left or right as mentioned here

Comma on the left allows one to comment out a line of code without rewriting it.

In general this is not the case since you can not comment out the first line. The JavaScript notation supports spare comma on the left as much as it supports spare comma on the right: Not at all.

Furthermore, current coding guidelines apply and should be followed. If you think comma on the left is a useful change, please post in the coding guidelines topic instead.

Of course you cannot comment out the first line, that's true no matter where a comma exists. But you can comment out lines within the middle of a function call or sql script if the comma is on the left.

For example a SQL statement all on one line (not standard, just for example)

Code: Select all

select a, b, c, d from table1, table2, table3 where join1 and join2 and join3

Same SQL statement formatted better, commas on the right:

Code: Select all

select a,
b,
c,
d
from table1,
table2,
table3
where join1
and join2
and join3

Where are the "and" connectors? On the left. Not like this:

Code: Select all

select a,
b,
c,
d
from table1,
table2,
table3
where join1 and
join2 and
join3

Comma on the left

Code: Select all

select a
, b
, c
, d
from table1
,table2
,table3
where join1
and join2
and join3

Now, other than the required SELECT and FROM and WHERE statements, any individual line of code can be commented / removed without editing any other line of code. If a comma or connector (like "and" as mentioned above) is on the right rather than on the left, this is not true.

I realize this is a religious war much like whether { } should be on their own line or not. But I feel that there are specific benefits to having a comma / connector left strategy that apparently were not apparent to the person who responded to my post in the other topic quoted above.

[Erik Frèrejean]

+1

I'm actually starting to utilise this style more and more on private projects. Especially in the "and" case the resulting query is a lot easier to read when just glazing over it.

[imkingdavid]

I like the AND on the left on the new line, but the comma on the left just looks ugly and is more difficult to type.

[drathbun]

...and is more difficult to type.

Really? That's your argument? , then CR is harder than CR then ,?

It's not a difficult change to get used it. I've written code like this for a long time, it's second nature at this point. But as I already said, I get that it's a style that some folks will like, some folks will not. I use the , to help with the indentation style as well.

Code: Select all

select  col1
,       col2
,       col3
from    tab1
,       tab2
,       tab3
where   join1
and     join2

[Oleg]

In my projects I now put trailing commas everywhere in javascript and have a post-processing pass to take them out before deployment.

I find leading punctuation ugly.

[callumacrae]

I also find leading punctuation extremely ugly, -1.

[drathbun]

Whatever. Ugly or "too hard to type" aren't objections that override the functional advantages in my opinion. That being said, I won't keep beating the horse. I made the suggestion, feel free to discuss or ignore.

[brunoais]

I accept the comma on the left in both js and PHP, the AND on the left, etc...
Still we need to make that in a correct way IYKWIM.
We'll need to keep that code formatted and readable.
Something like drathbun's example except you'd use caps for commands (SELECT, FROM, etc...) and functions.

Code: Select all

select  col1
,       col2
,       col3
from    tab1
,       tab2
,       tab3
where   join1
and     join2

I'll choose ±0 if you keep these conditions, -1 if you don't.

Edit:
This comma on the left, it allows you to add something and have git not say that two lines were changed, but... What happens if it's the 1st thing in the list that is removed and not the last one or one in the middle? We get to the same story, don't we? Comma on the left is better for adding, comma on the right is better for removing. It would just be better if there was a way to have the extra comma on the right without any complaints by the system....

[callumacrae]

This comma on the left, it allows you to add something and have git not say that two lines were changed, but... What happens if it's the 1st thing in the list that is removed and not the last one or one in the middle? We get to the same story, don't we? Comma on the left is better for adding, comma on the right is better for removing. It would just be better if there was a way to have the extra comma on the right without any complaints by the system....

The general idea is that you have the semi-colon on its own line:

Code: Select all

var a = 'b',
    , b = 'c'
    , c = 'd'
    , d = 'e'
    , e = 'f'
    ;

It looks horrific. -1 to sacrificing clean and pretty code for nicer diffs.

[imkingdavid]

Edit:
This comma on the left, it allows you to add something and have git not say that two lines were changed, but... What happens if it's the 1st thing in the list that is removed and not the last one or one in the middle? We get to the same story, don't we? Comma on the left is better for adding, comma on the right is better for removing. It would just be better if there was a way to have the extra comma on the right without any complaints by the system....

Exactly. Except in the case of PHP arrays, in which we can have trailing commas, we are going to have that change show up in Git in one case or another, whether we choose to have commas on the left or right.

I do not see the point in going through all the trouble to change this.