Need to use .set and .get

[sebmarkbage]

Need to use .set and .get

[nmn]

The problem is that a normal = can't work for most cases.

(I don't see any mention of .get and .set in the documents for vectors. (Which is probably an oversight))

For example, take the example of a vector.

var a = #[1, 2, 3, 4]

Now, of course, it should be possible to easily read values:

a[0] === 1

But you can't use assignment to update the vector:

a[0] = 9 // Doesn't work

This is because, by definition, these data structures are immutable.

a = a.set(0, 9)  // sadly there is no mentions of a .set in the docs so far.

This is actually the same way that strings work in Javascript:

var str = 'abc'
str = str + 'def'

str[1] === 'b'
str[1] = 'c' // doesn't work

The only way to assignment work reliably would be to create a new value on every assignment. This can technically work, but seems to be complicated and confusing for Javascript.

[natew]

Actually I apologize I wrote this late before I forgot about it but I don't think set is as important, just being able to get without explicit .get would be nice.

[nmn]

@natew I agree with the subscript based get. But It would only work for vectors and records, as Maps take non-string, non-number strings as well.

[andersekdahl]

As much as I'd like to be able to do avoid using .get and .set, I think that it's quite important to be able to polyfill this feature. Even though you could transform vector[0] to vector.get(0) the impossible part is to know when a variable is an immutable vector and not an array, which means that it cannot be polyfilled.

Index and property access without get/set can always be added at a later stage.

[nmn]

I agree that .get is something that would need to be kept around. That said subscripts would be a huge benefit as well.