It's common enough that it's supported like a comment by numerous syntax highlighting schemes, and has the added benefits of guaranteeing that the code won't be compiled as well as encapsulating any pre-existing block comments. Conversely, if (false) is total garbage.
A simple if (false) will get optimized out by any modern C or C++ compiler with optimizations on, but the problem is that the compiler will still parse and spend time on what's inside the if-block and it has to be legal code, whereas with the #if 0 trick the whole thing gets yeeted away by the preprocessor before even the compiler gets to look at it regardless of whether that block contains errors or not, it's literally just a string manipulation.
I think you missed the whole point of my comment 😂. Regardless, the time spent compiling a small snippet of code is completely negligible. In the end, both #if 0 and if (false) have their complimentary uses.
Yeah, but I still think if (false) is silly because it adds an artificial constraint which is to make sure the disabled parts always compile even when you're not using them. The equivalent of that would be having to check that all the revisions of a single source file compile against your current codebase.
If(false) works in interpreted languages, the other one doesn't. It's stupid either way, that's what version control is for, but if we are doing the stupidness anyway, you can't use preprocessor flags in many languages because shit doesn't get compiled.
I was going through some js code a few months ago and every function in a module had return; as its first line. And that module was imported into 4 or 5 scripts.
I don't see the need for an if block or renaming the function and leaving it there. It is extra unnecessary work for the compiler. Comments are probably the best way. Might also copy the current file, put the original in some folder like "old", and delete the old code inside the new copy.
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Very disappointing not to see an #if 0 (my personal go-to for decades) in this meme. 😞
Damn, you beat me to it.
It's common enough that it's supported like a comment by numerous syntax highlighting schemes, and has the added benefits of guaranteeing that the code won't be compiled as well as encapsulating any pre-existing block comments. Conversely, if (false) is total garbage.
If (false) is good because it is compiled so it doesn't get stale.
A simple
if (false)will get optimized out by any modern C or C++ compiler with optimizations on, but the problem is that the compiler will still parse and spend time on what's inside the if-block and it has to be legal code, whereas with the#if 0trick the whole thing gets yeeted away by the preprocessor before even the compiler gets to look at it regardless of whether that block contains errors or not, it's literally just a string manipulation.I think you missed the whole point of my comment 😂. Regardless, the time spent compiling a small snippet of code is completely negligible. In the end, both
#if 0andif (false)have their complimentary uses.Yeah, but I still think
if (false)is silly because it adds an artificial constraint which is to make sure the disabled parts always compile even when you're not using them. The equivalent of that would be having to check that all the revisions of a single source file compile against your current codebase.If(false) works in interpreted languages, the other one doesn't. It's stupid either way, that's what version control is for, but if we are doing the stupidness anyway, you can't use preprocessor flags in many languages because shit doesn't get compiled.
"you're not wrong, you're just an asshole"
Fair enough, I do love being contrarian
Tell this to my -Wall -Werror
beat me to it too, it's a meme of course but the advantage compared to comments is thay you get syntax highlighting 😁
My linter always skips preprocessors not set to build, in c# at least, greys it all out unfortunately
this is what I'm doing too, so at least it's not compiled and better than a /* */ as you can keep all the code intact in your #if 0
I was going through some js code a few months ago and every function in a module had
return;as its first line. And that module was imported into 4 or 5 scripts.You folks have clearly not met first year CS students. Screenshots code
laughing in
#if 0:bonus points if you use a different variable every file so they have to go through and change every instance if they want to make changes
If you're in a language that supports it, please don't use
if (false)useif ($disallowAllUsers = false && $whateverTheRealConditionIs)Never seen this, what language or buildsystem is this?
That specific language is PHP, but the tip is applicable in any language that supports inline assignment.
The assignment syntax is too close to comparison, which is what is more typical in that position. I would recommend
if not a proper feature flag (or just remove the code).
It seems much worse to use a setter in an if statement.
Think of it as inline attribution/documentation.
I don't see the need for an if block or renaming the function and leaving it there. It is extra unnecessary work for the compiler. Comments are probably the best way. Might also copy the current file, put the original in some folder like "old", and delete the old code inside the new copy.
Comments are the worst as they are ignored by refactoring. That's the reason if (false) is actually really good for temporarily disabled code.
I never thought of that. That's quite smart!
On a modern computer dead code analysis with constant folding should be nearly unnoticeable when compiling a large project
[Ctrl-V]69jI// [Esc]gc69j
what about relying on the persistent undo history in vim?
In Python you put it in a multiline string, since it has those but not multiline comments.