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Yet another way to invoke functions in JavaScript without parentheses

blog.ikaes.de

266 points by aragonite · 113 comments

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hans_castorp

This reminds me of "Creators admit Unix, C hoax" (e.g. https://www.gnu.org/fun/jokes/unix-hoax.html)

> We stopped when we got a clean compile on the following syntax:

    for(;P("\n"),R--;P("|"))for(e=C;e--;P("_"+(*u++/8)%2))P("| "+(*u/4)%2);
nathell

I love this. This is a fun hack, but the article also hearkens back to pre-LLM days when people were still interested in _code_.

  • bunderbunder

    I wonder if there was a period in the 90s where the chess community was more interested in talking about IBM’s stock price than in actually playing chess.

  • stymaar

    I'm definitely gonna use that for April 1st though, just adding this as instruction in Claude.md

    That will also serves as a litmus test to check how many of my coworkers are reading the code they push.

  • stigok

    Programmers are still interested in code

  • kpcyrd

    It feels like it's from back when we unironically thought memorizing quirks like this makes us better programmers, or is somehow important for making computers more secure, aka middle of the 2010s tech bubble.

MattCruikshank

I want to write a super pedantic book showing every way I can think of to move data from here, to there. In the same program, or between programs.

Global variable.

Parameter to a function.

Pass a functor/lambda, get the value.

Environment variable.

Registry.

File.

Store it in a ping response.

VRAM texture that you write and then read.

Database.

REST server.

I'm pretty sure I could come up with a thousand ways.

But... why? Why do I want to write this book? Why has it been on my mind?

  • vvill

    Reminds me of Harder Drives https://tom7.org/papers/murphy2022harder.pdf

    And something my friend wrote a few years ago: https://github.com/radian628/tram

    Data storage and transmission has so much innovation going on!

  • CoastalCoder

    You might be interested in the book "Data Flow Analysis" by Khedker et al.

    It's very compiler-focused, but it's one piece of the puzzle.

  • mycall

    Never forget RFC 1149 or KERMIT!

  • arethuza

    For some reason this made me think about all of the potential complexities that can be involved in CLOS in calling a generic function and some method(s) actually being invoked...

  • fwip

    Implement your own delay-line memory with the speaker, microphone, and echo of the room.

    • MattCruikshank

      I honestly thought of typing that one out here, lol.

      You have the camera... I have the monitor... How about I flash QR codes? Oh, the camera is on top of the monitor, facing the room? Well, at night, I could FLASH the monitor full white in binary, and you can see the light on the chair and wall, right?

      I'll leave the disc head on the sector number. You read the disc head position.

      I'll exit my function on a time modulo a number to encode the remainder. You see what time you were called, and can decode the remainder.

      I'll warm the CPU to a temperature... you read the temperature...

      The list goes on and on...

      "The Exfiltration Manual"...?

amelius

I want to put the called function after the arguments:

    (((x)f)g)h
So I can see exactly the order in which things happen, from left to right. As opposed to:

    f(g(h(x)))
where I have to read backwards.
  • bunderbunder

    One of the things I love about programming in dialects of ML like ocaml and f# is the forward pipe operator:

      x
      |> f
      |> g
      |> h
    
    
    It's nice because it just puts whatever's on the left of the operator in as the last argument. So it also works for functions with an arity of more than one.

    So if it were something like

      h(z, g(y, f(x))
    
    you can write it as

      x
      |> f
      |> g y
      |> h z
    
    
    It works really nicely for data munging code:

      my_data
      |> filter (x => x > 37)
      |> select (x => x * 2)
      |> sum
    
    but unlike doing it with method calls in object oriented code, inserting a new function into the chain doesn't involve modifying a class or or mucking around with more complex language features like extension methods and traits.
    • sparkie

      There's also function composition

         (h . g . f) x
      
      Or for LtR, with Control.Category

         (f >>> g >>> h) x
      
      Could combine with the forward pipe for

         x |> (f >>> g >>> h)
    • pfdietz

      Lisp macros let you do similar things, and you don't have to change the language itself.

      • tomsmeding

        In ML family languages you also don't have to change the language for this, as function application is naturally "argument-by-argument" (the term is "curried"): the syntax is normally f x y z but (f x y) z and (((f)) (x)) y z are just as valid, and indeed f x y will be a function taking one argument. Thus |> can just take a function of one argument and be done.

      • bunderbunder

        Maybe I've just been doing too much Racket lately and that's affecting how I view things, but it's real hard for me to not think of lisp macros as a mechanism for changing the language itself. Especially if it's something like a reader macro.

        • pfdietz

          A lot of Common Lisp is like this. They took things that were used to implement standard parts of the language, and went "you know, users might also want to have these", and exposed them as part of the standard. If I were to extend Common Lisp I'd standardize and expose more things like this.

      • FuckButtons

        You could say the same about more or less any language feature - the thing is though that having a standard feature people can agree on is better than several people’s divergent opinions on which macros are sufficiently aesthetically pleasing.

  • ktpsns

    Mathematica has a crazy amount of syntax abbreviations (https://reference.wolfram.com/language/guide/Syntax.html). Of course your whish is fulfilled there: x // f called the postfix operator.

  • danlitt

    Do you mean (((x)h)g)f ?

    since the order in which things happen is "h first, then g, then f"

  • mesrik

    So would you like to write shell commands connected with pipes like that too?

    So is this better too

      $ less | find / -type f -perm /6000 -ls
    
    than ?

      $ find / -type f -perm /6000 -ls | less
    
    Just because shell actually starts executables right to left when using pipes. Reason to this behaviour is because it can fail early if there is problem constructing pipe first and not spend lot of time something finding later that some pipe components can't start and receive data properly.

    ps. I'm fine with current notation and would not like change it.

    • unilynx

      I think he actually wants pipes. Instead of having to write:

        f3(f2(f1(some data)))
      
      it would be nice to write

        some data |> f1 |> f2 |> f3
      
      javascript has proposals for pipe operators because as soon as the simple .map /.filter/.reduce APIs don't suffice (ie. as soon as Promise.all is needed) the f3(f2(f1(data))) mess starts.
  • nine_k

    Did you even have an RPN-based calculator at school?

    As to more serious programming languages, Erlang, F#, Haskell have forms of a "pipe" operator, roughly

      [1 2 3] |> sum |> print
    
    For it to work properly, functions should be either functions of one argument, or support currying.

    But the original algebra functions, as introduced by Leibniz in 17th century, were, of course, pure functions, more like properties than procedures. So cos(x), aka cos x, is just a formalized shorthand for "cosine of x", so it preserved the order of words typical for Germanic and Romance languages. Maybe if functions were introduced by the Japanese, we would have the reverse order, kind of x の cos.

  • skocznymroczny

    Assuming you mean h)g)f, you can do it in D. D allows you to write this:

    f(g(h(x))) as x.h().g().f() or even x.h.g.f (parenthesis are optional).

  • adverbly

    That actually makes so much sense...

    When you're calling a function, you're putting some things into the function... You have to get the things first before you can put them in...

    Why didn't it evolve like that in the first place? Is it a byproduct of mathematical notation? If so, I wonder why mathematical notation evolved that way in the first place...

    • baruchel

      Forth (or Postscript by the way) works exactly like that, but writing the function first also makes sense in functional programming, specifically when you care about currying functions: writing "f(g(h(x)))" (or "f g h x" or whetever) makes more sense, since you are not supposed to put all expected arguments at once.

      • arethuza

        Do you have to write a function first before it is referenced in PostScript? (I did a lot of PostScript programming in NeWS once - but it was ~35 years ago...)

    • stronglikedan

      > Why didn't it evolve like that in the first place?

      It did, just in Arabic.

  • ashkankiani

    Stack based languages and the APL tradition all follow this pattern, which I agree can be more terse and nice too. I've also been experimenting with right-associative calls which does the same thing but in reverse. For a data pipeline you're more likely to transform from A->B, so I think the post-fix syntax makes sense.

    But you can also define a "thread" operator easily for doing subsequent function calls. ala `threaded x { f; g; h }`

  • taolson

    In a lazy language like Haskell, the order in which things are actually evaluated is f -> g -> h -> x, because arguments to a function are only evaluated when the are needed, rather than before they are called. But even so, I still prefer writing it as x |> h |> g |> f.

  • layer8

    If `f` is an expression, that would require it to be evaluated last as well.

  • account42

    This is why some languages have the | pipe syntax for chaining operations.

  • anal_reactor

    I want to put the function below the arguments, so that the call tree actually looks like a tree

        u v x y
         f   g
           h
    
    This is h(f(u,v), g(x,y)).
    • amavect

      I've thought about this before. It gets harder when dealing with >2 inputs and names longer than 1 letter, so I organized it with lines to make it look more tree-like.

        │u│v│x│y
        ├─┴─├─┴─
        │f  │g
        ├───┴─
        │h
        └─
      
      With >2 inputs and longer names.

        │uh│v  │xizzy│yeez
        ├──┴─  ├─────┴────
        │fooey │gar
        ├──────┴───
        │hello
        └─────
      
      The associative property.

        (a+b)+c=a+(b+c)=a+b+c
      
        │a│b    │b│c
        ├─┴─    ├─┴─
        │+  │c│a│+  │a│b│c
        ├───┴─├─┴─  ├─┴─┴─
        │+    │+    │+
        ├─────┴─────┴─
        │=
        └─
      
      The quadratic formula.

        (-b±sqrt(b^2-4*a*c))/(2*a)
        
          │b│2│4│a│c
          ├─┴─├─┴─┴─
          │^  │*
          ├───┴─
        │b│-    
        ├─├─    
        │-│sqrt│2│a
        ├─┴────├─┴─
        │±     │*
        ├──────┴─
        │/
        └─
      
      Obviously, it takes way more space and time to draw. Tell me if you like it!
  • kiicia

    you can start with

        var chain = x=>f=>f?chain(f(x)):x;
        chain(x)(h)(g)(f)();
    
    if you need to partly curry to free first argument

        var _ = (f,...y)=>x=>f(x,...y);
        var sum = (x,y)=>x+y;
        chain(1)(_(sum,1))()
    
    if you want whole pipeline

        var $ = (x,...f)=>f.reduce((x,f)=>f(x),x);
        $(1,_(sum,1));
    
    which gives fun ability to extract function without input param

        var sum1 = _($,_(sum,1));
        sum1(1);
    
    ... which in turn is just having fun with point-free JS
  • raverbashing

    And that's why "purely procedural" languages don't make much sense to me

    It's more natural to write

        x.h().g().f()
  • Rohansi

    The function reference is actually evaluated first so your preferred order is actually backwards! Consider this:

      foo.bar(x)
    
    The `foo.bar` field has to be retrieved before the function can be called. It does not evaluate `x` first. That is observable with JS proxies, or you can test with code like this:

      foo()(bar())
    • LtWorf

      Executing the "." operator isn't the same as executing the function.

      • Rohansi

        JS and many other languages have getters so that's not always true.

        But my point is that the reference to the function you are calling is actually its own term that needs to be considered in the order of evaluation.

        You can also use the IIFE (immediately invoked function expression) pattern that is/was common in JS as an example:

          (function() {
            // ...
          })();
        
        You can use any valid expression in place of a function name, including anything that causes observable side effects.
        • LtWorf

          A "getter" executed on the "." operator isn't the same as executing the function it returns anyway.

CrendKing

Not gonna work on Firefox, since according to the doc, Error.prepareStackTrace is an optional API and only implemented by V8.

  • fg137

    > optional API and only implemented by V8

    aka "Chrome implemented this and wanted everyone else to do so as well"

pards

Off topic: This website looks like a ransom note

TheSilva

  Object.prototype.message='alert\x281337\x29';Array.prototype.toString=Error.prototype.toString;Error.prepareStackTrace = Function;const x = new Error;x.valueOf=x.stack;+x;
Well, that's a mouthful! So many years and JavaScript still can do the most amazing, weird, awesome, scary, obscure, and sexy things in the world of coding.
  • fg137

    The prototype thing is quite unique among mainstream languages. It is kind of simple in principle and works well for what it intends to do, but god it causes so much confusion and is frequently a source of CVEs. valueOf combined with implicit conversion is a nightmare for production code.

  • customguy

    Yesterday I was re-using some shaders I had written a long time ago, and here's what I used to do multiline strings before the glorious backtick arrived on the scene...

        (function () {/*
          my awesome shader code
        */}).toString().match(/[^]*\/\*([^]*)\*\/\}$/)[1]
    
    ... I can't call it sexy, but I also can't deny I felt a mixture of fear and arousal when I saw that.
    • annex-winged-cr

      TIL about [^], never seen that before. Apparently, it works like a dot but it also matches newlines.

      • chii

        I believe this is the regular syntax for a set of characters (between "[" and "]"), but the caret symbol ("^") is negation when used inside the set. Therefore, it is simply the negation of an empty set of characters.

      • gmac

        Oh, me too. I’ve previously used [\s\S] for that.

    • h43z

      Pretty interesting that you can carry comments over.

          (x=>/*this is a comment*/1) + 1
          "x=>/*this is a comment*/11"
      
      I wonder if anything cool can be done with it today. It's probably useless.
semiquaver

JavaScript is so cursed.

  • user____name

    If I were to write a book on programming in JS, it would be a black cover with the JS Holy Trinity equality diagram in red, to emphasize its Satanic nature.

    • toolslive

      Satanic? never assume malice where incompetence suffices

      • hk__2

        Don’t assume either malice or incompetence when it’s just that you don’t understand the context and the reasons things are this way.

        • marcosdumay

          The reason is that the language was designed in a week with a "product manager" pushing the developer's design into something that only has "is a programming language" in common with it during that week.

          The sooner that abomination is killed, the best.

          • NetMageSCW

            Prototype based languages existed before Javascript and even before Self. It wasn’t an adhoc or new idea.

          • diegof79

            The prototype ("Mocha") was created in a week, but the language went through multiple iterations. (See https://www.wirfs-brock.com/allen/jshopl.pdf)

            Honestly, I can point you to languages with worse design than JS.

            There was an idea (perhaps from BASIC) that "scripting" means permissive. Instead of failing fast, it was designed to fall back to something that works (e.g., '1'+1=2). That's a terrible design decision, and JS tried to reverse it in every future iteration.

            The other two big issues for me were: trying to imitate Java (with the new keyword, instanceof, and null). The prototype mechanism that JS took from Self is simpler and easier to understand if you leave out those constructs.

            The other issue was the lack of modules. That was part of the idea that JS was for short, interactive scripts on a page; the initial version didn't plan for how we use it today.

            Other than that, I prefer JS over Perl, C, C++, PHP, shell scripting, or TCL.

            Edit: Actually, '1'+1 is '11' in JS (facepalm), but '1'*2 converts to a number. That's why it was a terrible idea. But, to be fair, many "scripting" languages did that kind of type coercion. I guess that language designer hated cryptic compile errors.

sharktheone

TC39 member here; There are a lot more ways in JS to call a function without parenthesis. The first thing to come to my mind is Symbol.isConcatSpreadable or Symbol.iterator which works in multiple places

jlhawn

> without parentheses

> \x28

> \x29

does this not count as using parentheses?

  • rafram

    Not when it comes to bad input sanitizers that only look for literal "()".

airtnp

Could this be used in obfuscation? We should try to apply it and see if LLM can deobfuscate it.

aktenlage

What's the purpose of the +x at the end?

shevy-java

It is called ... Ruby.

(Though, parentheses are sometimes needed due to ambiguity. But by and large, the lispy legacy has been overcome already.)

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