Re: Rant after trying Rust a bit

[Andrei Alexandrescu via Digitalmars-d]

On 7/22/15 5:36 PM, jmh530 wrote:
On Wednesday, 22 July 2015 at 20:43:04 UTC, simendsjo wrote:
When "everything" is an expressions, you can write things like
    auto a = if(e) c else d;
In D you have to write
    type a = invalid_value;
    if(e) a = c;
    else  a = d;
    assert(a != invalid_value);



I prefer this example from one of the various Rust tutorials

let foo = if x == 5 {
                 "five"
           }
           else if x == 6 {
                 "six"
           }
           else {
                 "neither"
           }

You're basically using a conditional expression as an rvalue. You can do
the same thing with a { } block.

I used to be quite jazzed about the everything-is-an-expression mantra, 
but it's not all great.

1. Inferring function return types when everything is an expression 
(i.e. last expression there is the return type) may yield WAT results.

2. Defining a result type for loops is awkward.

At the end of the day everything-is-an-expression is natural for 
functional languages, but doesn't seem it makes a large difference to an 
imperative language.

To OP: thanks for your rant! Instead of getting defensive we'd do good 
to derive action items from it.


Andrei