How to convert u8 into u64 in sway v0.45?
Hello guys! In continuing to rewrite all the composability labs code on the fuel testnet beta4 toolchain I ran into another problem, in this case, it’s our predicate-based central limit orderbook spark.
We have a mechanism in CLOB to cancel orders by inputting zero tokens from the order creator with an output to the creator’s address. To test this case we need to check if the predicate creator is the owner of at least one of the inputs.
To do this, we get the total number of inputs using the function std::inputs::input_count, it returns a number of type u8. After that we check the address of the owner of the order with the address of a particular input in a loop using the function std::inputs::input_owner.
fn main() -> bool {
let mut i = 0;
let inputs = input_count();
while i < inputs {
if input_owner(i).unwrap() == Address::from(MAKER) {
return true;
}
i += 1;
}
...
The problem is that std::inputs::input_owner accepts u64 type as an argument, and the counter i can only be of u8 type (it became mandatory with beta4). I don’t understand how to cast u8 to u64, conversion methods like as u64 or .into() don’t work
The error:
error
--> /Users/alexey/Desktop/spark-rs/limit-order-predicate/src/main.sw:30:15
|
28 |
29 | let inputs = input_count();
30 | while i < inputs {
| ^^^^^^ Mismatched types.
expected: u64
found: u8.
help: This argument's type is not castable to the declared parameter type.
31 | if input_owner(i).unwrap() == Address::from(MAKER) {
32 | return true;
|
____
Aborting due to 1 error.
Error: Failed to compile limit-order-predicate
How to reproduce the problem
git clone https://github.com/compolabs/spark-rs.git
cd spark-rs
git checkout beta-4
cd limit-order-predicate
forc build
Toolchain
Default host: aarch64-apple-darwin
fuelup home: /Users/alexey/.fuelup
installed toolchains
--------------------
beta-3-aarch64-apple-darwin
beta-4-rc.2-aarch64-apple-darwin
latest-aarch64-apple-darwin (default)
hotfix
my-custom-toolchain
active toolchain
-----------------
latest-aarch64-apple-darwin (default)
forc : 0.44.1
- forc-client
- forc-deploy : 0.44.1
- forc-run : 0.44.1
- forc-doc : 0.44.1
- forc-explore : 0.28.1
- forc-fmt : 0.44.1
- forc-index : 0.20.7
- forc-lsp : 0.44.1
- forc-tx : 0.44.1
- forc-wallet : 0.3.0
fuel-core : 0.20.4
fuel-core-keygen : Error getting version string
fuel-indexer : 0.20.7
fuels versions
---------------
forc : 0.45
forc-wallet : 0.45
