Hi Greg, There is no warning for omitting the return type when the braces are omitted. The compiler infers the return type from the body expression. I thought about requiring the infer-types compiler option for that, but considering that it is all new syntax, I feel like maybe it just makes sense to allow it.
Yes, the generated JS currently matches how I emulated arrow functions in SWF. I’d like to use real JS arrow functions in the future, but I figured that I could start with this and improve it later. I’ve been dealing with a family emergency, and I plan to take some personal time, so I wanted to commit this as a good enough starting point to gather feedback. -- Josh Tynjala Bowler Hat LLC https://bowlerhat.dev/ On Fri, Jul 18, 2025 at 9:37 AM Greg Dove <greg.d...@gmail.com> wrote: > Nice work, Josh! > > I just tried with > var test:Function = () => true; > > Is that supposed to be ():Boolean => true ? > > fyi if it is, I did not see a warning (I don't think) > > I assume you are simply outputting the same 'conversion' for swf in the js > output at the moment ? > > > > > On Fri, Jul 18, 2025 at 2:37 PM Harbs <harbs.li...@gmail.com> wrote: > > > Awesome! :-) > > > > > On Jul 18, 2025, at 1:48 AM, Josh Tynjala <joshtynj...@bowlerhat.dev> > > wrote: > > > > > > Hey folks, > > > > > > I just wanted to highlight a new AS3 language feature that I have > > recently > > > implemented in the Royale compiler: arrow function expressions! > > > > > > If you're not familiar, these were added to JavaScript a while back. > Here > > > are the MDN docs for the JS version: > > > > > > > > > https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/Arrow_functions > > > > > > Basically, they have two main advantages. > > > > > > 1. They have shorter syntax. > > > 2. They can use the `this` variable from the enclosing function's > scope. > > > > > > Here's a simple example: > > > > > > var func:Function = (name:String) => "Hello, " + name; > > > func("Royale"); > > > > > > - No function keyword (uses => instead) > > > - Optional return type (it may be inferred from the return value) > > > - Optional braces around the function body, if it contains a single > > > expression > > > - If braces are omitted, no need for a `return` keyword > > > > > > You could rewrite the same arrow function like this, without everything > > > omitted: > > > > > > var func:Function = (name:String):String => { > > > return "Hello, " + name; > > > } > > > > > > Technically, this is valid too: > > > > > > var func:Function = name => "Hello, " + name; > > > > > > However, it will report a warning because the name parameter type is > > > missing, so that's not recommended. > > > > > > -- > > > Josh Tynjala > > > Bowler Hat LLC > > > https://bowlerhat.dev/ > > > > >
