Strings do too many things

Comments

• fubo@lemmy.world ⁨9⁩ ⁨months⁩ ago

  Any time you’re turning a string of input into something else, what you are doing is parsing.

  Even if the word “parser” never appears in your code, the act of interpreting a string as structured data is parsing, and the code that does parsing is a parser.

  Programmers write parsers quite a lot, and many of the parsers they write are ad-hoc, ill-specified, bug-ridden, and can’t tell you why your input didn’t parse right.

  Writing a parser without realizing you’re writing a parser, usually leads to writing a bad parser. Bad parsers do things like accepting malformed input that causes security holes. When bad parsers do reject malformed input, they rarely emit useful error messages about why it’s malformed. Bad parsers are often written using regex and duct tape.

  Try not to write bad parsers. If you need to parse something, consider writing a grammar and using a parser library. (If you’re very ambitious, try a parser combinator library.) But at least try to recall something about parsers you learned once way back in a CS class, before throwing regex at the problem and calling it a day.

  (And now the word “parser” no longer makes sense, because of semantic satiation.)

  source

  • ono@lemmy.ca ⁨9⁩ ⁨months⁩ ago

    By the way, please don’t write regex to try to validate email addresses. Seriously.

    Amen.

    There are libraries for that; some of them are even good.

    Spoiler alert: Few of them are good, and those that are so simple that you might as well not use a library.

    The only way to validate an email address is to send a message to it, and verify that it arrived.

    source

    • Jesus_666@feddit.de ⁨9⁩ ⁨months⁩ ago

      You can use a regex to do basic validation. That regex is .+@.+. Anything beyond that is a waste of time.

      source

      • -> View More Comments
    • fubo@lemmy.world ⁨9⁩ ⁨months⁩ ago

      The only way to correctly validate an email address is to send a message to it, and verify that it arrived.

      If you’re accepting email addresses as user input (e.g. from a web form), it might be nice to check that what’s to the right of the rightmost @ sign is a domain name with an MX or A record. That way, if a user enters a typo’d address, you have some chance of telling them that instead of handing an email to user#example.net to your MTA.

      But the validity of the local-part (left of the rightmost @) is up to the receiving server.

      source

      • -> View More Comments
  • grue@lemmy.world ⁨9⁩ ⁨months⁩ ago

    By the way, please don’t write regex to try to validate email addresses. Seriously.

    Speaking of things you can’t parse with regex…

    You can’t parse [X]HTML with regex. Because HTML can’t be parsed by regex. Regex is not a tool that can be used to correctly parse HTML. As I have answered in HTML-and-regex questions here so many times before, the use of regex will not allow you to consume HTML. Regular expressions are a tool that is insufficiently sophisticated to understand the constructs employed by HTML. HTML is not a regular language and hence cannot be parsed by regular expressions. Regex queries are not equipped to break down HTML into its meaningful parts. so many times but it is not getting to me. Even enhanced irregular regular expressions as used by Perl are not up to the task of parsing HTML. You will never make me crack. HTML is a language of sufficient complexity that it cannot be parsed by regular expressions. Even Jon Skeet cannot parse HTML using regular expressions. Every time you attempt to parse HTML with regular expressions, the unholy child weeps the blood of virgins, and Russian hackers pwn your webapp. Parsing HTML with regex summons tainted souls into the realm of the living. HTML and regex go together like love, marriage, and ritual infanticide. The <center> cannot hold it is too late. The force of regex and HTML together in the same conceptual space will destroy your mind like so much watery putty. If you parse HTML with regex you are giving in to Them and their blasphemous ways which doom us all to inhuman toil for the One whose Name cannot be expressed in the Basic Multilingual Plane, he comes. HTML-plus-regexp will liquify the n​erves of the sentient whilst you observe, your psyche withering in the onslaught of horror. Rege̿̔̉x-based HTML parsers are the cancer that is killing StackOverflow it is too late it is too late we cannot be saved the transgression of a chi͡ld ensures regex will consume all living tissue (except for HTML which it cannot, as previously prophesied) dear lord help us how can anyone survive this scourge using regex to parse HTML has doomed humanity to an eternity of dread torture and security holes using regex as a tool to process HTML establishes a breach between this world and the dread realm of c͒ͪo͛ͫrrupt entities (like SGML entities, but more corrupt) a mere glimpse of the world of reg​ex parsers for HTML will ins​tantly transport a programmer’s consciousness into a world of ceaseless screaming, he comes, the pestilent slithy regex-infection wil​l devour your HT​ML parser, application and existence for all time like Visual Basic only worse he comes he comes do not fi​ght he com̡e̶s, ̕h̵i​s un̨ho͞ly radiańcé destro҉ying all enli̍̈́̂̈́ghtenment, HTML tags lea͠ki̧n͘g fr̶ǫm ̡yo​͟ur eye͢s̸ ̛l̕ik͏e liq​uid pain, the song of re̸gular exp​ression parsing will exti​nguish the voices of mor​tal man from the sp​here I can see it can you see ̲͚̖͔̙î̩́t̲͎̩̱͔́̋̀ it is beautiful t​he final snuffing of the lie​s of Man ALL IS LOŚ͖̩͇̗̪̏̈́T ALL I​S LOST the pon̷y he comes he c̶̮omes he comes the ich​or permeates all MY FACE MY FACE ᵒh god no NO NOO̼O​O NΘ stop the an​*̶͑̾̾​̅ͫ͏̙̤g͇̫͛͆̾ͫ̑͆l͖͉̗̩̳̟̍ͫͥͨe̠̅s ͎a̧͈͖r̽̾̈́͒͑e n​ot rè̑ͧ̌aͨl̘̝̙̃ͤ͂̾̆ ZA̡͊͠͝LGΌ ISͮ̂҉̯͈͕̹̘̱ TO͇̹̺ͅƝ̴ȳ̳ TH̘Ë͖́̉ ͠P̯͍̭O̚​N̐Y̡ H̸̡̪̯ͨ͊̽̅̾̎Ȩ̬̩̾͛ͪ̈́̀́͘ ̶̧̨̱̹̭̯ͧ̾ͬC̷̙̲̝͖ͭ̏ͥͮ͟Oͮ͏̮̪̝͍M̲̖͊̒ͪͩͬ̚̚͜Ȇ̴̟̟͙̞ͩ͌͝S̨̥̫͎̭ͯ̿̔̀ͅ

    Have you tried using an XML parser instead?</center>

    source

    • derpgon@programming.dev ⁨9⁩ ⁨months⁩ ago

      The best validation for a valid email address is always sending a verification mail. I’ve rejected countless MRs that contained ad-hoc regex email validation copied from the internet. I’d allow a check for it to contain an @.

      source

      • -> View More Comments
    • MinekPo1@lemmygrad.ml ⁨9⁩ ⁨months⁩ ago

      Honestly I feel like PHP regex may be able to parse html but not entirely sure

      source
  • abhibeckert@lemmy.world ⁨9⁩ ⁨months⁩ ago

    Programmers write parsers quite a lot

    Speak for yourself. I’ve done it exactly once. It didn’t work, and never shipped.

    source

    • oscar@programming.dev ⁨9⁩ ⁨months⁩ ago

      So you have never iterated over command line arguments and tried to identify options? Or taken a string input field?

      source
• darkmatternoodlecow@programming.dev ⁨9⁩ ⁨months⁩ ago

  Yeah! And integers do way too many things as well. Counters, indexes, number of orange slices in an orange, there’s just no end to the wacky things people try to make integers do, and it’s impossible to keep track of it all when looking at code. And floats? Don’t get me started on floats. Angles, probabilities, weights, heights, degrees of separation from Kevin Bacon … I’m getting dizzy just listing all these different things that floats do.

  It’s a big problem, because there isn’t an easy way to fix it in every programming language known to man, and someone needs to write more articles about this to get more hits for their sites.

  source

  • andrew@lemmy.stuart.fun ⁨9⁩ ⁨months⁩ ago

    Wait till you hear what strings are under the hood. Integers in a trench coat!

    source

    • darkmatternoodlecow@programming.dev ⁨9⁩ ⁨months⁩ ago

      And the boolean is revealed as the archvillain working behind the scenes, pulling the strings of all its minions.

      source

      • -> View More Comments
    • jaybone@lemmy.world ⁨9⁩ ⁨months⁩ ago

      It’s integers all the way down.

      source
  • tias@discuss.tchncs.de ⁨9⁩ ⁨months⁩ ago

    I think the article makes a good point, but perhaps I’m over-interpreting. It’s not that we should stop using strings. It’s that we should use the type system to separate different kinds of strings and enlist the compiler’s help to detect incorrect mingling of them. So for example a Symbol type would only permit strings that contain ASCII letters, underscore and digits, and concatenation would be limited.

    source
  • dudinax@programming.dev ⁨9⁩ ⁨months⁩ ago

    What’s the meaning of a fractional “Degree of Kevin Bacon”?

    source

    • kogasa@programming.dev ⁨9⁩ ⁨months⁩ ago

      The analytic continuation of KB(x) to the complex plane subject to a superconvexivity constraint is unique but doesn’t necessarily have a straightforward geometric interpretation

      source
  • chickenf622@sh.itjust.works ⁨9⁩ ⁨months⁩ ago

    It’s definitely a rule that can be taken so far that it is counterproductive, but I think it’s good practice to thbk about how I could use something other than a raw string ( even if it’s just a constant defined somewhere )

    source
  • corytheboyd@kbin.social ⁨9⁩ ⁨months⁩ ago

    You joke, but Rails actually does literally make Integer do too many things lol. I’d argue they’re useful things, but it does so by patching the core Ruby Integer class :p

    source
• corytheboyd@kbin.social ⁨9⁩ ⁨months⁩ ago

  Strings became ubiquitously used for a reason, they map really clearly to the way we think as humans. Most importantly, when you’re debugging, seeing string data is much friendlier than whatever data your symbols map to (usually integers, from enum structures)

  No, obviously it’s not the most efficient thing in the world, but it hardly matters, and you’re not getting anyone to stop because you’re “technically right”.

  source

  • Pipoca@lemmy.world ⁨9⁩ ⁨months⁩ ago

    Symbols display with friendly string-y names in a number of languages. Clojure, for example, has a symbol type.

    And a number of languages display friendly strings for enemy things - Scala, Haskell, and Rust spring to mind.

    The problem with strings over enums with a nice debugging display is that the string type is too wide. Strings don’t tell you what values are valid, strings don’t catch typos at compile time, and they’re murder when refactoring.

    The other problem the article mentions is strings over a proper struct/adt/class hierarchy is that strings don’t really have any structure to them. Concatenation strings is brittle compared to building up an AST then rendering it at the end.

    source
• vzq@lemmy.blahaj.zone ⁨9⁩ ⁨months⁩ ago

  As a physicist, I agree ;)

  source
• mvirts@lemmy.world ⁨9⁩ ⁨months⁩ ago

  Despite all my rage I’m still just some bytes in a page

  source
• state_electrician@discuss.tchncs.de ⁨9⁩ ⁨months⁩ ago

  Man, stop overthinking stuff.

  source
• thingsiplay@beehaw.org ⁨9⁩ ⁨months⁩ ago

  Sounds like skill issues and depends on the context. Is this article about JavaScript? I recommend trying out Rust. Strings do only too many things, if you do it. Create your own types and enums. An example missing in the article are file or url paths. Use the standard libraries and types that are given to you.

  source
• Venator@lemmy.nz ⁨9⁩ ⁨months⁩ ago

  Unless you’re using assembly, strings do everything, since the code files are also strings.

  source
• demesisx@infosec.pub ⁨9⁩ ⁨months⁩ ago

  …and that’s why I use monadic parsers at the input boundary.

  source
• Jakdracula@lemmy.world ⁨9⁩ ⁨months⁩ ago

  Is that your theory?

  source