FA12.ligo

fa12.ligo

function mint (const value : nat ; var store : store) : return is
 block {
  // Fail if is not an owner
  if not isOwner(sender, store) then failwith("You must be an owner of the contract to mint tokens");
  else block {
    var ownerAccount: account := record 
        balance = 0n;
        allowances = (map end : map(address, nat));
    end;
    case store.accounts[sender] of
    | None -> skip
    | Some(n) -> ownerAccount := n
    end;

    // Update the owner balance and totalSupply
    const newBalance :nat = ownerAccount.balance + value;
    patch ownerAccount with record [balance = newBalance];
    store.accounts[sender] := ownerAccount;

    store.totalSupply := store.totalSupply + value;
  }
 } with (emptyOps, store)

function burn (const value : nat ; var store : store) : return is
 block {
  // Fail if is not an owner
  if not isOwner(sender, store) then failwith("You must be an owner of the contract to burn tokens");
  else block {
    var ownerAccount: account := record 
        balance = 0n;
        allowances = (map end : map(address, nat));
    end;
    case store.accounts[sender] of
    | None -> skip
    | Some(n) -> ownerAccount := n
    end;

    // Check that the owner can spend that much
    if value > ownerAccount.balance 
    then failwith ("NotEnoughBalance");
    else skip;

    // Check totalSupply
    if value > store.totalSupply 
    then failwith ("TotalSupply is too low");
    else skip;

    // Update balances and totalSupply
    const newBalance :nat =  abs(ownerAccount.balance - value);
    patch ownerAccount with record [balance = newBalance];
    store.accounts[sender] := ownerAccount;

    store.totalSupply := abs(store.totalSupply - value);
  }
 } with (emptyOps, store)