Implement unary operator execution

[Razican]

I just noticed that we haven't implemented all unary operators in execution.

• UnaryOp::IncrementPost (a++)
• UnaryOp::IncrementPre (++a)
• UnaryOp::DecrementPost (a--)
• UnaryOp::DecrementPre (--a)
• UnaryOp::Minus (-a)
• UnaryOp::Plus (+a)
• UnaryOp::Not (!a)
• UnaryOp::Tilde (~a)
• UnaryOp::Delete (delete)
• UnaryOp::Void (void)

This is implemented in boa/src/exec/mod.rs, around line 296.

I think that the "pre" increment/decrement operators, along with the typeof and void operators should be easy to implement, and good for newcomers to Boa.

The "post" increment/decrement operators will be challenging, as we currently always fully evaluate an AST node before continuing, and these need to be evaluated afterwards. The delete operator will be challenging too, I think.

After this is done, in #304 I have implemented some tests that are currently ignored, and we can probably start running them.

[jasonwilliams]

Did you want to close jasonwilliams#118 in favour of this?

[Razican]

Did you want to close #118 in favour of this?

Actually, I didn't notice that one, but I think there are two things in there. That issue showed that the parsing was broken. That has been solved. Now the issue is not a bug, it's that we don't have that implemented.

So I would say we should close the issue, as the bug is already fixed, and that we should implement the execution.

I already did a small change in #304, and changed the unreachable!() for an unimplemented!(). It should give a better error message.

[akryvomaz]

I think it makes sense to remove UnaryOp::TypeOf form the list because of the #359

[Razican]

I think it makes sense to remove UnaryOp::TypeOf form the list because of the #359

Yep, let's remove it!