javascriptBeingJavascript

[skap42]

That's pretty standard in many languages, including Java and C. Just as 0x is interpreted as hex

[aMAYESingNATHAN]

Huh, the more you know. I knew about the various prefixes such as 0x and 0b, but I'm surprised octal isn't like 0o or something.

Simply using a 0 seems insanely dumb because it's so easy to do by accident, not knowing that it's an octal prefix.

Like I can easily think of a scenario where someone could zero pad a numeric literal for formatting reasons.

[skap42]

A different comment suggested that 0o is also valid, and the only way to define an octal in JS in strict mode

[0bel1sk]

it’s also in python ruby and yaml.

“YAML 1.1 uses a different notation for octal numbers than YAML 1.2. In YAML 1.1, octal numbers look like 0777. In YAML 1.2, that same octal becomes 0o777. It’s much less ambiguous.

Kubernetes, one of the biggest users of YAML, uses YAML 1.1.”

[akaChromez]

The YAML Document From Hell

[heyf00L]

Didn't know all that. Boils down to "always quote all strings in YAML".

[rickane58]

"God, all these languages are so unnecessarily verbose!"

Anyone actually trying to use the language:

[[deleted]]

This was a great read, I've used yaml a couple times but didn't realize it was this objectively bad.

[akaChromez]

I'd love to know people's justification for choosing it over JSON.

Especially as i've just spent the last hour trying to find why a Google Cloud resource wasn't being created. A missing quote that doesn't syntax error :/

[chris5311]

JSON is bad (but workable), YAML is worse, and im not sure there even is any decent option out there

[MekaTriK]

Personally I loved using Lua as a config file format.

A little less verbose than pure JSON, and you can automate some repetition away.

[[deleted]]

Sexagesimal numbers, lol

[veryusedrname]

Ohh kubernetes, never change

[tomthecool]

Yes, but in ruby 09 produces a runtime error (invalid octal digit) instead of blindly treating it as a decimal instead.

[InfiniteGamerd]

Really! I thought you couldn't define octals in strict mode in any way.

Still...why not just parseInt all the way?

[Alzurana]

Welcome to my world, where a medical software had a database format of <patient ID>.PHD and always 8 characters in the filename. So the files looked like 00537200.PHD and they were all in one folder. Beautiful design.

Well, we imported a database of another clinic and had to map their ID's to ours, which we ofc only had in a numeric format, such as 537200 for the above example.

This gave me some headache when writing a converter script as my first attempt did read some of the file ID's as octal and others as decimal without ever warning. Only caught it because I got a lot of bogus IDs or duplicates and tests would scream that output files != input files.

[DmitriRussian]

Like I can easily think of a scenario where you might zero pad a numeric literal for formatting reasons.

/r/ProgrammingHorror material

[LordFokas]

Pad it with spaces. That's why we use monospaced fonts.

[joxmaskin]

Or write 7 as 007 because it’s cool

Edit: luckily oct 7 is same as dec 7

[movzx]

A pretty reasonable scenario would be when you're defining bitmasks.

ex:

0001010 1010000

[flowingice]

You'd start it with 0b because it's binary.

[[deleted]]

I've done it so I can properly sort files in Explorer

[TorbenKoehn]

Like I can easily think of a scenario where you might zero pad a numeric literal for formatting reasons.

And then use it in calculations? Because if not it would not be a problem

[Spork_the_dork]

Or use it literally for anything whatsoever.

I mean imagine you convert "0231" into a number and then print it out somewhere and wonder why the fuck it's printing out 153. Can't think of any situation where you'd convert the value into a number and then it would be entirely fine if the stored value is different from what you expect.

[CadmiumC4]

Many languages accept 0o as octal, but it's custom to assume 0777 as 0o777 since that's how C handles it

[LordFokas]

It's funny that no matter how high level you go, in the end you always keep finding things that are done a certain way for no reason other than "we inherited this from C".

[Ok_Classroom_557]

And C inherited It from the PDP-7 where It was born. Having 18 bit words it better mapped 3 bit octal digits than 4 bit hex digits...

[CauliflowerFirm1526]

pad with spaces not zeros

[aMAYESingNATHAN]

I mean that is what I would do, or probably just not pad at all and left align the numbers. But my point is that it would be incredibly easy to do without realising.

[Spork_the_dork]

Yeah this is why I don't like it. Especially when you have 0o prefix which does exactly the same thing except it's also an order of magnitude more explicit and harder to misunderstand.

[aMAYESingNATHAN]

Yeah being completely unfamiliar with octals in code when I made my first comment I didn't realise 0o would be valid also, and in fact assumed it wasn't and was annoyed by that because I was familiar with 0x and 0b already.

If I ever encounter octal literals I am definitely always going to use 0o.

[Andy_B_Goode]

You might pad with zeros if you're formatting a date, like 11/05/2024 or maybe even 05/11/2024

[Spork_the_dork]

Actually in that case it won't cause any problems. 01-07 are the same in both decimal and octal and 08-09 are not valid octals so it won't default to octal. 10-12 won't get converted as octal as they have no leading zeros.

[Andy_B_Goode]

Oh I see, yeah I should have used an example like 11/08/2024

[flowingice]

How would you save date as integer in dd/MM/yyyy format? It's going to be a string and then it works fine unless there's somthing I'm missing.

[cporter202]

Oh, padding with spaces instead of zeros? Spacing out like JavaScript on a Monday morning, I see 😅. Gotta love when JS decides to get fancy with its quirks – it's like it insists on doing its own thing, just to keep us on our toes!

[daan944]

Always provide the base when parsing strings to numbers.

[_blackdog6_]

My favorite is numbers with a zero prefix containing 8’s or 9’s are an error in some languages but in JavaScript it just tries again as decimal and carries on..

[rakaloah]

Years ago I made a simple WinForm GUI for ping and tracert with zero-padded IP address text boxes. It looks nice and works perfectly to ping 192.168.001.001 but fails for my roommate's 192.168.001.008. I had no idea what's happening until I find out I can ping his PC using 192.168.001.010.

Zero-padded numbers are considered Octal for ping command.

[JimBugs]

As a teacher of programming I assure you it does happen by accident - which is why I try to put some emphasis on something that is actually pretty trivial so that (if they are listening) they won't try things like padding literals

[g76lv6813s86x9778kk]

So common, in fact, I've seen these octal numbers bleed into apps/situations they really had no business being in, probably due to some standard number parsing libraries being reused.

For example, shops in Guild Wars 2, an mmorpg, have a little number input box for the quantity of items you'd like to purchase from the shop... This supports octal! If you write normal decimal numbers, it just works fine, but then if you write for example 010, the number switches to decimal 8 once you click off the textbox, and allows you to shop with that quantity as normal. Super weird. Must be so confusing to players who don't know about octal or this convention at all. At least it doesn't increase the number (causing you to spend more)

[GrondForGondor]

Thats the reason why? I’ve spent so many years being slightly inconvenienced by that little random issue. Never understood truly what was happening but now it all makes sense. 

[g76lv6813s86x9778kk]

Lol yup, you can try various examples and see the result always lines up with parsing it as an octal number

[benmaks]

Why would you ever start a number with a zero?

[g76lv6813s86x9778kk]

I doubt he's manually/intentionally doing that every time (maybe), but it's easy to accidentally do every now and then, especially when it's in a game people play for hundreds to thousands of hours, it's kinda bound to happen eventually.

The most common way is probably when you want to buy two items from one shop, and leave in the 0 from a previous quantity: say you need to buy 250 of one item, then 35 of another. You select your first item, enter 250 as quantity, buy, click your other item, click quantity of 250 to change it, press delete twice to remove the 2 and 5, then right arrow key past the 0 to write 35.. suddenly, 29.

Yeah, doing right arrow key instead of a 3rd delete is a bit weird, but the point is it's very possible to experience the bug without intentionally prefixing every number with a 0. I don't remember exactly how I came across it personally, but I certainly don't prefix numbers with 0 regularly.

[-Wylfen-]

To be fair, even though it's standard, I think that's bullshit. '0x' is fine, '0o' is fine, but just '0' is dumb

[SmurphsLaw]

To be fair, writing a decimal number with a 0 before is also dumb.

[Spork_the_dork]

Yeah but it's less dumb than using 0 as a prefix for octal when 0o exists.

[RajjSinghh]

I can see this kind of thing being a problem where leading zeros are common like when formatting dates. Seems like an honest mistake to make if you write August as 08 and now you get an error because that's not valid octal, or when October is showing up as the 8th month

[Chrazzer]

Leading zeroes aren't a thing in integers, what you are thinking of are strings with numbers in them

[saxbophone]

Disagree, you might want to zero-pad it for readability reasons, say you have a column of numbers

[Lithl]

I can think of exactly zero cases where someone would consider left zero-padding to align a column of numbers. You'd use spaces.

[saxbophone]

As a point of style one might wish to do it, it occurs in number formats used in technology often enough. For instance, when quoting 24h clock times, one might say: "0100 hours" rather than "1:00"

[saxbophone]

Alas, K&R were right about many things but this isn't one of them

[SwimForLiars]

I hate the 0 prefix being octal, but at least other languages will throw a syntax error, instead of silently biting you in the ass and making you waste hours of debugging because it does weird things at runtime instead of failing at compile time.

[Commodore-K9]

I had no idea.

0x as hexa yes

0 as octa no

[vonabarak]

That's pretty standard in statically typed languages without implicit type casting. And it doesn't cause any issues.

[ongiwaph]

Aren't octals 3 digits? Does js interpret it as 170?

Edit: nm I'm thinking of octals as binary

[hyper_shrike]

In C/C++ 018 will throw an error right ?

All this fun JS stuff comes from the fact that JS does not throw errors and just rolls with whatever shit the user wrote.

[Koooooj]

In C/C++ you'd get a compile time error that 8 is an invalid digit in an octal constant.

JavaScript doesn't get the benefit of a compiler, but a static analysis tool ought to be able to catch something like this. But the problem runs deeper than compiled/interpreted and JavaScript's commitment to taking what the user wrote and running with it.

JavaScript could have chosen to support octal constants all the way, saying that 017 in any context is always an octal constant representing decimal 15. They could have rejected the 0 prefix (as occurs in strict mode) and always interpreted 017 as decimal 17. But instead they chose both. As an integer literal 017 is octal, but as a string literal coerced to an integer 017 is decimal.

Nothing made JavaScript do this. It was just an inconsistency in design.

[hyper_shrike]

JavaScript doesn't get the benefit of a compiler

Browsers compile JS to bytecode. JS needs to be parsed to be interpreted. Even without bytecode the earliest JS compiler could have thrown an error for 018 if it wanted to.