0

Is it somehow possible to do something like this?

contract Test {
    function test (bool isTransaction) public view {
        if (isTransaction) {
          foo();
        }

        ...
    }
    
    function foo () public {
        ...
    }
}

In the best case I would be able to call test() like an usual view/pure function without the need of making a transaction but if isTransaction is true test() requires me to make a transaction in order to call it. Maybe I can throw an exception or something similar to be able to compile and run this code?

EDIT: bool transaction got bool isTransaction

2
  • I think foo() must be pure or view, so no
    – Majd TL
    Apr 4 at 13:34
  • I saw the answer, but I still don’t get it :/ maybe I’m messing something or u are making it complicated. For me -> if u know it is a transaction then call foo directly, if not then call a normal view function that has nothing to do with foo :/ it is always better to reduce the logic in smart contract as much as u can
    – Majd TL
    Apr 4 at 20:31
2

You can accomplish something like this using staticcall:

contract Test {
  function test (bool transaction) public view {
    if (transaction) {
      (bool success,) = address(this).staticcall(abi.encodeWithSignature("foo()"));
      require(success, "Contract call failed");
    }
  }
    
  function foo () public {
    // ...
  }
}

This will compile, and test will execute without errors as long as foo() does not modify the state. If foo() does modify state, it will revert because success is false.

5
  • interesting didn't think about that, but where can we use such a thing or logic :/?
    – Majd TL
    Apr 4 at 16:25
  • I´m not sure what you mean by "where can we use such a thing or logic"?
    – Morten
    Apr 4 at 16:29
  • For calling foo() I need to make a transaction so is it possible to call test() making an transaction if isTransaction is true and if not I call test() like a normal view function so without needing a transaction?
    – Paulus
    Apr 4 at 16:33
  • I edited the question because it was not quite clear what I wanted although @Morten's answer comes closer to what I need
    – Paulus
    Apr 4 at 16:38
  • @Morten I mean what is the purpose of a view function that call a normal function based on a given parameter :) in other words any useful use case for that
    – Majd TL
    Apr 4 at 20:08
1

the answer is no. it will not compile

view functions cannot modify the state and the compiler check this and give you back

TypeError: Function declared as view, but this expression (potentially) modifies the state

Tested it with solidity 0.8.3

enter image description here

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