The => in CoffeeScript or ES6 is often useful for binding this to a function, especially in callbacks. I can't seem to find an alternative in LiveScript. Does it exist?
It's ~>.
Answer courtesy of _rgn on the #livescript channel on freenode.
Related
I use Python, but I don't know how it works in Kotlin. This is an example
example => exec("""print("hello")""") output => hello
exec("""print("hello")""") output => hello
Kotlin supports JSR-223. You can use the jvm scripting engine to eval kts files.
val engine = ScriptEngineManager().getEngineByExtension("kts")
engine.eval("""print("hello")""")
You need JSR-223 library dependency. Refer to example
implementation("org.jetbrains.kotlin:kotlin-scripting-jsr223:$kotlinVersion")
Short answer: this isn't practical in Kotlin.
Technically, there may be ways, but they're likely to be far more trouble than they're worth; you're far better looking for a different approach to your problem.
Unlike a dynamic (‘scripting’) language like Python, Kotlin is statically-compiled. In the case of Kotlin/JVM, you run the Kotlin compiler to generate .class files with Java bytecode, which is then run by a JVM.
So if you really need to convert a string into code and run it, you'd have to find a way to ensure that a Kotlin compiler is available on the platform where your code is running (which it often won't be; compiled bytecode can run on any platform with a JVM, and most of those won't have Kotlin installed too). You'd then have to find a way to run the compiler; this will probably mean writing your source code out to a file, starting up the compiler program as a separate process (as I don't think there's an API for calling it directly), and checking the results. Then you'd have find the resulting bytecode and load into the JVM, which will probably mean setting up a separate classloader instance.
All of which is likely to be slow, fragile, and very awkward.
(See these previous questions which cover some of the same ground.)
(The details will be different for Kotlin/JS and Kotlin/Native, but I think the principles are roughly the same.)
In general, each computer language has its own approach, its own mind-set and ways of doing things, and it's best to try to understand that and accept that patterns and techniques from one language don't always translate well into another. (In the Olden Days™, it used to be said that a determined programmer could write FORTRAN programs in any language — but only in satire.)
Perhaps if you could explain why you want to do this, and what sort of problem you're trying to solve (probably as a separate question), we might be able to suggest more natural solutions in Kotlin.
Is there alternative for #SuppressWarnings("WeakerAccess") in kotlin?
I've tried #Suppress("WeakerAccess") but no luck. It's pretty annoying to see "Function xxx could be private" when developing a library.
Write test code in src/test/kotlin that makes use of your functions.
How to call validate.js and use it in feature file (to verify a specific part of the response)?
I am trying to use https://github.com/validatorjs/validator.js which is a library with some awesome validators out-of-the-box.
While reading the Karate documentation there is a way to read / call and read .js files, so I taught there has to be a way to do this. https://intuit.github.io/karate/#schema-validation
I gotten this far but: ReferenceError: "isNumeric" is not defined in at line number 1
var validator = require('validator');
* def isNumeric = validator.isNumeric ;
In a scenario:
And match each response/list/costs/numberX == '#? isNumeric(_)'
I feel I am really close...
Unfortunately as of now Karate supports only ES5 (via Nashorn) and also does not support JS "module" concepts such as the import or require keywords.
Personally I think this is a good thing, the more JS you use, the more unmaintainable your scripts become. And there is no good way to debug. Note that Karate has syntax to do "functional style" loops and transformations.
Also I have found that in most of the cases where you think JS is needed, Karate's built-in schema validation is sufficient or a better choice.
That said, we hope that when we switch to Graal (proposed, and a must for Java 13+) we will be able to use ES6+ and I am personally looking forward to the arrow notation for functions.
I have an errors.rs file with error_chain! {}, which exports Result, ResultExt, Error and ErrorKind.
If I use self::errors::*, IntelliJ thinks that I'm using the default Result (std::result::Result, I think). However, if I explicitly import the types using use self::errors::{Result, ...}, everything works out hunky dory.
I can tell because the standard result has two type params, but the error_chain one has only one.
In either case, it still compiles.
I'm using the standard Rust IntelliJ plugin, version 0.1.0.1991.
Help! Does anyone know how to get the plugin to understand what the macro is doing?
The IntelliJ-Rust plugin uses its own code parser. It allows to leverage all the IntelliJ platform capabilities (like code navigation, formatting, refactoring, inspections, quick documentation, markers and many others) but requires implementing all the language features, which is not a simple task for Rust (you can find a more in-depth discussion of the Rust compiler parser versus IDE parser in this reddit post).
Macros expansion is probably the biggest language feature that is not supported by the plugin parser at the moment. That is, the plugin sees this error_chain! call, can resolve it to its definition, but doesn't expand it to the actual code and hence doesn't know about the new Result struct that shadows the one from stdlib. Unfortunately, in some cases it leads to such false positive error messages.
I've converted this error annotation into an inspection, so in the next plugin version you'll be able to switch it off entirely or for the particular code block. The work on macros expansion is also in progress.
I'm new to hapi.js and I would try test it out. Is it possible to develop with Hapi.js and coffeescript? Could you supply some example on how to setup hapi.js with coffeescript.
I thought the same approach would be useful. From CoffeeScript.org:
The golden rule of CoffeeScript is: "It's just JavaScript". The code compiles one-to-one into the equivalent JS, and there is no interpretation at runtime. You can use any existing JavaScript library seamlessly from CoffeeScript (and vice-versa). The compiled output is readable and pretty-printed, will work in every JavaScript runtime, and tends to run as fast or faster than the equivalent handwritten JavaScript.
If you know CoffeeScript, then you should be able to translate all examples into CoffeeScript by yourself. Else, you should learn CoffeeScript.
Copy and paste any example code into http://js2.coffee and it will show you how it may look like in coffeescript.
And yes you could easily use coffeescript also with hapi like:
Hapi = require 'hapi'
server = new Hapi.Server()
server.connection
port: 3000
server.start ->
console.log 'Server running at:', server.info.uri