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Cake day: May 31st, 2020

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  • Yeah, I’m just saying that the benefit of using such a regex isn’t massive (unless you’re building a service which can’t send a mail).

    a@b is a syntactically correct e-mail address. Most combinations of letters, an @-symbol and more letters will be syntactically correct, which is what most typos will look like. The regex will only catch fringe cases, such as a user accidentally hitting the spacebar.

    And then, personally, I don’t feel like it’s worth pulling in one of those massive regexes (+ possibly a regex library) for most use-cases.



  • Well, and remember: If in doubt, send them an e-mail. You probably want to do that anyways to ensure they have access to that mailbox.

    You can try to use a regex as a basic sanity check, so they’ve not accidentally typed a completely different info into there, but the e-mail standard allows so many wild mail addresses, that your basic sanity check might as well be whether they’ve typed an @ into there.


  • I always hated the implementation for .toString() of Duration. It gives you a string like that: PT8H6M12.345S (not a hash)

    Apparently, it’s an ISO 8601 thing, but what the hell am I supposed to do with that?
    It’s not useful for outputting to end users (which is fair enough), but I don’t even want to write that into a log message.
    I got so used to this just being garbage that I would automatically call .toMillis() and write “ms” after it.

    Well, and not to gush about Rust too much, but I recently learned that its debug string representation is actually really good. As in, it’s better than my Java workaround, because it’ll even do things like printing 1000ms as 1s.
    And that’s just like, oh right, libraries can actually provide a better implementation than what I’ll slap down offhandedly.



  • Yeah, I came to Rust from Scala and Kotlin, where equality is default-implemented (for case class and data class respectively, which is basically all we ever used), so this meme surprised me a bit.

    I do actually like that you can decide a type cannot be compared, because sometimes it really just doesn’t make sense. How would you compare two HTTP clients, for example? But yeah, it certainly is a choice one can disagree with.


  • I find these videos give a very visual explanation and help to put you into the right mindset: http://intorust.com/
    (You can skip the first two videos.)

    Sort of when it clicked for me, was when I realized that your code needs to be a tree of function calls.
    I mean, that’s what all code is anyways, with a main-function at the top calling other functions which call other functions. But OOP adds a layer to that, i.e. objects, and encourages to do all function calls between objects. You don’t want to do that in Rust. You kind of have to write simpler code for it to fall into place.

    To make it a bit more concrete:
    You will have functions which hold ownership over some data, typically because they instantiated a struct. These sit at the root of a sub-tree, where you pass access to this data down into further functions by borrowing it to them.

    You don’t typically want to pass ownership all over the place, nor do you typically want to borrow (or pass references) to functions which are not part of this sub-tree.
    Of course, there’s situations where this isn’t easily possible, e.g. when having two independent threads talking to each other, and then you do need Rc or Arc, but yeah, the vast majority of programming problems can be solved with trees of function calls.