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Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

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Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#11

Post by leononame »

gmassman wrote: post #5
dudul wrote: post #3

Earlier quoted context omitted.

> I'm sick of having to type everything twice, like e.g. `%{foobar: foobar}` I'm actually very confused by this use case. How often do you have to do that? Fill a map with kv tuples where keys and values have the exact same value?

This pattern appears frequently in just about all programming languages. I’ve written a lot of JS and Python, and a moderate amount of Elixir, and this pattern crops up quite often. Usually it’s a side effect of complex scopes with several layers of function calls. Honestly I’m a little surprised you haven’t seen this pattern. The only times it wouldn’t be used are when people rename variables, which is frankly a pra…

JS and python are just about all programming languages?

I'm not trying to be snarky, but e.g. I haven't seen it in Go, F# and Rust, some languages where I have at least seen _some_ code. I also don't remember a similar pattern in Java, C# and C nor PHP or Dart, but I will readily admit that it's I haven't coded in any of these in the last two years, so I might be a bit out of touch and I'm not super proficient in all those languages

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#12

Post by boxed »

leononame wrote: post #11
gmassman wrote: post #5

Earlier quoted context omitted.

This pattern appears frequently in just about all programming languages. I’ve written a lot of JS and Python, and a moderate amount of Elixir, and this pattern crops up quite often. Usually it’s a side effect of complex scopes with several layers of function calls. Honestly I’m a little surprised you haven’t seen this pattern. The only times it wouldn’t be used are when people rename variables, which is frankly a pra…

JS and python are just about all programming languages? I'm not trying to be snarky, but e.g. I haven't seen it in Go, F# and Rust, some languages where I have at least seen _some_ code. I also don't remember a similar pattern in Java, C# and C nor PHP or Dart, but I will readily admit that it's I haven't coded in any of these in the last two years, so I might be a bit out of touch and I'm not super proficient in all…

Go, and F# do almost all positional arguments. I think Rust too. Java, C#, C, PHP are also positional only or 99% of the time. I assume Dart too.

We are talking named/keyword/etc.

Personally I find positional arguments to be an anti-pattern in all but a very specific set of circumstances.

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#13

Post by MrJohz »

jzimbel wrote: post #8

This was done previously with the `short_maps` library, which the author—a member of the Elixir core team—eventually retired and archived due to regrets from the undesirable impacts on clarity. https://github.com/whatyouhide/short_maps https://andrealeopardi.com/posts/a-story-of-regret-and-retir...

That's quite surprising to me. As someone who writes a lot of Javascript, I usually find it easiest to read with this syntax than without it, and I generally recommend to my team that they use the shorthand where they can. This is because the meaning is clear and well-known, and being concise (while still being clear) is very valuable.

I wonder what specifically the original author found made it more difficult to read. Was it unfamiliarity? They allude to some confusion between sigils and strings, so I wonder if the issue was partly an Elixir-specific one.

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#14

Post by aarongraham »

jzimbel wrote: post #8

This was done previously with the `short_maps` library, which the author—a member of the Elixir core team—eventually retired and archived due to regrets from the undesirable impacts on clarity. https://github.com/whatyouhide/short_maps https://andrealeopardi.com/posts/a-story-of-regret-and-retir...

I really don’t understand why some people are so against this as a language feature. I get that the community tries to stay away from “magic” but where is the line between magic and convenient syntactic sugar.

For example keyword lists as the last argument to a function don’t need brackets, and keyword lists are really lists of tuples where the first item is an atom. I feel like those two things are in some ways less obvious and more magical than this map shorthand.

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#15

Post by karmajunkie »

rubyn00bie wrote: post #10

I personally don’t think this is a good idea, and I think the formatter plugin is going to give someone insane amounts of regret one day. It’s neat as “look what I did” but Elixir is all about removing magic. It (lack of magic) is one of the things I appreciated most, having originally come from Ruby and Rails. I’ve been using it professionally for nearly ten years, and I can say this isn’t a feature I’ve ever really…

i don’t like adding foundational syntax using libraries, but i do wish they would add this to the language. deconstruction by pattern is super common and the syntactic sugar would be most welcome.

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#16

Post by debugnik »

boxed wrote: post #12
leononame wrote: post #11

Earlier quoted context omitted.

JS and python are just about all programming languages? I'm not trying to be snarky, but e.g. I haven't seen it in Go, F# and Rust, some languages where I have at least seen _some_ code. I also don't remember a similar pattern in Java, C# and C nor PHP or Dart, but I will readily admit that it's I haven't coded in any of these in the last two years, so I might be a bit out of touch and I'm not super proficient in all…

Go, and F# do almost all positional arguments. I think Rust too. Java, C#, C, PHP are also positional only or 99% of the time. I assume Dart too. We are talking named/keyword/etc. Personally I find positional arguments to be an anti-pattern in all but a very specific set of circumstances.

C#, F# and PHP all support named arguments and they're quite common for optional parameters.

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#17

Post by pflanze »

leononame wrote: post #11
gmassman wrote: post #5

Earlier quoted context omitted.

This pattern appears frequently in just about all programming languages. I’ve written a lot of JS and Python, and a moderate amount of Elixir, and this pattern crops up quite often. Usually it’s a side effect of complex scopes with several layers of function calls. Honestly I’m a little surprised you haven’t seen this pattern. The only times it wouldn’t be used are when people rename variables, which is frankly a pra…

JS and python are just about all programming languages? I'm not trying to be snarky, but e.g. I haven't seen it in Go, F# and Rust, some languages where I have at least seen _some_ code. I also don't remember a similar pattern in Java, C# and C nor PHP or Dart, but I will readily admit that it's I haven't coded in any of these in the last two years, so I might be a bit out of touch and I'm not super proficient in all…

If we're talking about constructing structs, like in `Foo { bar, baz: 123 }` (with the `bar` style shortcut in it), I have used that kind of syntax 10 times in 16 KLOC of Rust. Not a lot, but it does happen, and I found it kinda neat when LSP integration suggested its use.

I've probably used it more for pattern matching (`let Foo { bar, baz } = ...`), but haven't measured the number of instances of that idiom.

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#18

Post by vessenes »

A good reminder that macros give you super powers!

I don't know a lot of elixir, so I can't say if this is a great idea for inclusion into the standard or not, but it's undeniable that giving macro-based access to the AST adds a lot of expressivity and flexibility.

Re: Show HN: es6_maps, new Elixir syntax feature via runtime compiler hacking

#19

Post by hhreefgguu »

aarongraham wrote: post #14
jzimbel wrote: post #8

This was done previously with the `short_maps` library, which the author—a member of the Elixir core team—eventually retired and archived due to regrets from the undesirable impacts on clarity. https://github.com/whatyouhide/short_maps https://andrealeopardi.com/posts/a-story-of-regret-and-retir...

I really don’t understand why some people are so against this as a language feature. I get that the community tries to stay away from “magic” but where is the line between magic and convenient syntactic sugar. For example keyword lists as the last argument to a function don’t need brackets, and keyword lists are really lists of tuples where the first item is an atom. I feel like those two things are in some ways less…

Magic == “I don’t like it, but I want to sound more objective or rational than I really am”.

You’re definitely correct that there’s as good an argument that these implicit features you mention are “too magical” as there is the the “ES6” syntax is too magical.

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