Why do delegate class methods `getValue` and `setValue` need to marked with `operator` keyword?

# getting-started

[Alexander Suraphel]

Why do delegate class methods getValue and setValue need to marked with operator keyword?

[henrikhorbovyi]

to be accessed like:

val message: String by delegate

[Alexander Suraphel]

I thought so! But I don’t see anywhere in the doc that by is an operator, just a soft keyword

[henrikhorbovyi]

yeah 🤔 actually by can be used on simple classes too
https://kotlinlang.org/docs/delegation.html

[Alexander Suraphel]

Yeah your link mentions by as clause not an operator, right?

[henrikhorbovyi]

image.png

[henrikhorbovyi]

and in observable delegate, setValue and getValue are not operators

[henrikhorbovyi]

so, idk 😄

[Alexander Suraphel]

Actually ReadWriteProperty which ObservableProperty inherits from defines them as `operator`s 🙂

[henrikhorbovyi]

yeah, that's true blob thinking upside down

[Alexander Suraphel]

I’ve created a StackOverflow question just in case.

[Alexander Suraphel]

@henrikhorbovyi someone answered the question perfectly on SO. You might want to check it out.

[henrikhorbovyi]

ooh... cool

[andylamax]

by is an operator. It operates on getValue and setValue. If the docs is missing that, then its something that has to be added