Why does Uniswap not have payable functions ?

[TilakMaddy]

At least for the v1 where we know it's weth why not just have payable functions to directly pay eth to the contract? Isn't it more convenient than transferFrom(..) because that needs approvals and stuff. They could have avoided all that !

[PatrickAlphaC]

Great question! This is a common confusing part for engineers.

payable functions only work for eth or native gas token functions.

For example:

function doStuff() public payable {
  require(msg.value > 1); 
}

You actually can't transferFrom with ETH/Native Gas tokens!

ERC20s on the other hand, need to use functions like transferFrom since they are smart contracts themselves.

They don't need to be payable, since they don't use ETH!

function doStuff() public {
  IERC20(some_address).transferFrom(address_a, address_b, amount);
}

Does that make sense?

[TilakMaddy]

Yes 👍

[KulzeinepHub]

Ok!

[Mixaakisev]

thx bro

[Vasilii098]

thx, gj

[Avkubs]

This is a quality solution