Haxe tips: everything is an expression

In Haxe, nearly everything is an expression. (Things that aren’t: import statement, class declaration etc, which are at module level). And every expression can be evaluated to a value.

A block is an expression that is evaluated to the last expression inside the block:

var v = {
    //some code

It can be used for list comprehension:

var oneToTen = {
    var a = [];
    for (i in 0...10) a.push(i+1);
trace(oneToTen); //[1,2,3,4,5,6,7,8,9,10]

In reverse, we can notice many things actually use any expression instead of only a block.

Function declaration:

function hello() return "world";

For loop:

for (i in 0...5) trace(i); //0 1 2 3 4

And of course if-else:

if (a > 100)
    trace("a is more than 100");
else if (a > 50)
    trace("a is between 50 and 100");
    trace("a less than 50");

If-else itself is an expression too. So we can simplify the above to:

trace(if (a > 100) "a is more than 100" else if (a > 50) "a is between 50 and 100" else "a less than 50");

Of course we can use the equivalent ternary operator, but in my opinion it is a bit less readable:

trace(a > 100 ? "a is more than 100" : a > 50 ? "a is between 50 and 100" : "a less than 50");

Switch is useful to be used as an expression when working with enum:

enum Color {
    Rgb(r:Int, g:Int, b:Int);

class Main {
    static function main():Void {
        var redColor = Rgb(255,0,0);
        var red = switch(redColor) {
            case Rgb(r,g,b): r;
            default: throw "not rgb color";

And actually try-catch also returns a value:

var noException = try {
    //some code
} catch (exception:Dynamic) {

Do you find any other good use of anything as an expression?

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