When my coworker doesn't want to believe his code is inconsistent, yet he changes the syntax for commenting 3 times over 10 lines.

Programming standards and code reviews should sort this out. Inconsistent comments probably aren't that big a deal in the grand scheme of things but if they can't do that constantly what else are they up to.

Wait what?

Which language would support ALL of the following comment syntax? O__0

// ...
/* ... */
# ...

Code looks like PHP or something. Which I had no idea also supported #-comments

@theImposter it is true. But you can find this kind of problems absolutely everywhere, not only in comments. Everyday is a new adventure, discovering new ways and mostly badly written things.
At least, it works...

@corscheid PHP indeed.

at least he comments

@corscheid in PHP, // and # denote one-line comments

/*
...
*/ is supposed to be used for block comments and (in theory) using it for line comments wastes CPU time because it takes slightly longer to parse.

@hrombach true, I knew about block comments with /**/, I was saying I had no idea that

# this can be 1-line comment in PHP
// This is how I thought it must be

@corscheid C++ has the same three types and I think many other languages inherited them too.

I always associated comment syntax like this:

// AND /**/
for languages like C, C++, Java, PHP..

#
For languages like Perl, Python, Bash..

Despite the fact that # is technically acceptable for comments in PHP, I still don't feel right using it. // Works just as well and seems more stylistically preferred/'correct'

@corscheid I agree actually, I don't use # comments in PHP code either. And whenever I get a PR that has # comments I usually change them to // before I merge. 😆

@hrombach Pretty sure PHP is the wrong language if you have to care about how fast the comments are being parsed

@Kimmax firstly: not so true anymore since PHP 7
Secondly: that's why I added "in theory"

@lucasgrelaud It is consistent with the code for example, in spanish:

if ( persona.Nombre.esValido ) {
guardar(persona);
}

It is inconsistent, besides a non-spanish speaker wouldn't understand it.

@lucasgrelaud exactly my point