How to create a modifier costs(for an ERC20)? (Payable in erc20)?

Support Contracts
1

You can create a modifier that costs to call(need to pay an amount to call).

contract Owner {
 modifier costs(uint price) {
      if (msg.value >= price) {
         _;
      }
   }
}

https://www.tutorialspoint.com/solidity/solidity_function_modifiers.htm

My questions, how do you make the same thing, but require it to be payable not in base currency(eth, bsc,...) but in an ERC20 token?

Thanks in advance!

2

Tell me if I am wrong:
You want to create a modifier that checks the amount of tokens deposited?

3

Yeah. But for ERC20 token and not "ether"

4

You need to use trasnsferFrom and the contract must have enough allowance to take tokens from the user. You could use a dapp with an APPROVE button, like pancake that calls the "approve" function on the token.
Unfortunatly you can't call approve function of an erc20 from a contract passing the user address.

If you do:

token.approve(msg.sender, amount)

The contract will approve itself

5

This is wrong. The contract will not approve itself.

6

Did you try it? I think it is as I said but if I am wrong forgive me