CODEWITHSUNDEEP
compiler-errorssolidityremix
Charlie_83
Charlie_83

Reputation: 11

Solidity Expected unidentified error in smart contract code - Remix

The compiler reports the error attached below; pretty strange as I am following the course's tutor, who suggested me to use an older version of remix, I read in similar questions that 'returns' should be singular but his code compile without issues, I tried anyway, didn't work; he is using ^0.4.11 I am running on ^0.8.4 even though the issue persisted when I downgraded to a previous version.

Error:

ParseError: Expected '{' but
got 'constant' -->
tests/pendulum_ico.sol:28:60: |
28 | function 
equity_in_pendulum(address 
investor) external constant 
returns (uint) { | ^^^^^^^^

Code:

pragma solidity ^0.8.3;

contract pendulum_ico {
    
// Introducing the maximum number of Pendulum available for sale

    uint public max_pendulum = 1000000;
    
// Introducing the USD to Pendulum conversion relocatable

    uint public usd_to_pendulum = 1000;
    
// Introducing the total number of Pendulum that have been bought by the investors

    uint public total_pendulum_bought = 0;
    
// Mapping from the investor address to its equity in Pendulum and usd_to_pendulum

    mapping(address => uint) equity_pendulum;
    mapping(address => uint) equity_usd;
    
// Checking if an investor can buy Pendulum

    modifier can_buy_pendulum(uint usd_invested) {
        require (usd_invested * usd_to_pendulum + total_pendulum_bought <= max_pendulum);
        _;
    }
    
// Getting the equity in Pendulum of an investor

    function equity_in_pendulum(address investor) external constant returns (uint) { 
        return equity_pendulum[investor];
    }                             
    
// Getting the equity in USD of an investor

    function equity_in_usd(address investor) external constant returns (uint) {
        return equity_usd[investor];
    }
    
// Buying Pendulum 

    function buy_pendulum(address investor, uint usd_invested) external
    can_buy_pendulum(usd_invested) {
        uint pendulum_bought = usd_invested * usd_to_pendulum;
        equity_pendulum[investor] += pendulum_bought;
        equity_usd[investor] = equity_pendulum[investor] / 1000;
        total_pendulum_bought += hadcoins_bought;
        
    }
    
// Selling Pendulum 

    function sell_pendulum(address investor, uint pendulum_sold) external {
        equity_pendulum[investor] -= pendulum_sold;
        equity_usd[investor] = equity_pendulum[investor] / 1000;
        total_pendulum_bought -= pendulum_sold;
    }
    
}

Upvotes: 1

Views: 267

Answers (1)

Petr Hejda
Petr Hejda

Reputation: 43481

From the breaking changes list between 0.4 a and 0.5:

Using constant as function state mutability modifier is now disallowed.

In 0.8, you can also declare the function as a view function, which meets the state immutability criteria defined in the 0.4 constant.

function equity_in_pendulum(address investor) external view returns (uint) { 
    return equity_pendulum[investor];
}

Upvotes: 1

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