Microfeatures I'd like to see in more languages

Post by cpurdy » Sun, Jan 08, 2023, 12:43 AM UTC

tobyhinloopen wrote: post #148

Elixir’s testing library uses meta programming to show the code that fails and what the values were at both sides of a comparison. IE a = 1; b = 2 assert a == b Will fail with error like: Assertion failed, a == b Left is 1 Right is 2 So you don’t have a bunch of assert-functions; you just assert anything and it will spit out a decent error.

    val a = 1;
    val b = 2;
    assert a == b;

    IllegalState: a == b, a=1, b=2

Post by cpurdy » Sun, Jan 08, 2023, 1:05 AM UTC

nicoburns wrote: post #91

One of the best truly micro features I've seen recently (can't remember which langauge unfortunately - it wasn't a mainstream one), is general binary literal syntax of the form: 0x[de ad be ef 00] So much nicer than the usual condensed format. And I think it'd be valid syntax in any language that allows binary integer literal.

    Byte[] bytes = #|12 34 56
                    |78 9a BC
                    |dE f0
                   ;

    console.println($|bytes=
                     |{bytes.toHexDump(4)}
                   );

  bytes=
  00: 12 34 56 78 .4Vx
  04: 9A BC DE F0 .¼Þð

Post by pas » Sun, Jan 08, 2023, 10:32 AM UTC

brabel wrote: post #405

dima_vm wrote: post #351

Absolutely damned is combination of Kotlin's several features: 1. Lambda functions can be defined with `{}`. 2.`foo(bar, somefunc)` is the same as `foo(bar) somefunc`. In other words, if the last parameter is a function, it can be provided AFTER closing parenthesis. 3. Interfaces that require only one method can be implemented on-side with a lambda function (i.e. `{}` syntax for no-param function). Combined those thr…

All of these were copied from Groovy, in case you didn't know it.

Post by still_grokking » Sun, Jan 08, 2023, 7:59 PM UTC

Aaargh20318 wrote: post #221

amalgamated_inc wrote: post #45

Elixir's sigils are amazing. There are date sigils that allow you to do what the OP does: ~N[2023-01-01 12:00:00] But you can also define your own sigils to create new "custom syntax" for almost any struct. Kind of a special case of reader macros, I guess. Very convenient.

Swift has the expressibleby Type literal series of protocols for this. For example you could write an extension on Date to add initialization from a string: extension Date: ExpressibleByStringLiteral { public init(stringLiteral value: String) { // parse the string here. } } You can then do things like: let happyNewYear: Date = “2023-01-01 12:00:00” There are a protocols for all literal types. For example, you could i…

Post by still_grokking » Sun, Jan 08, 2023, 8:10 PM UTC

pas wrote: post #495

brabel wrote: post #405

Earlier quoted context omitted.

All of these were copied from Groovy, in case you didn't know it.

It reminds me of Scala too, but I have no idea which started when. And of course both could have come up with this fairly independently. (After all it is the norm in functional style.)