storagemapvec

Overview

StorageMapVec is a temporary workaround for implementing a StorageMap<K, StorageVec>. See why you cannot use StorageMap<K, StorageVec> directly in this issue. This library will be deprecated when that issue is resolved.

More information can be found in the specification.

Known Issues

StorageMapVec, like its predecessors (StorageMap, StorageVec) cannot be used recursively or multiple times (in a struct) for the same storage variable, or else it will overwrite its previous values.

Using the Library

Using the StorageMapVec library In Sway

Once imported, using the StorageMapVec library is as simple as making a storage variable and then calling the methods on it. Here is an example. For more information please see the specification.

Example

use sway_libs::storagemapvec::StorageMapVec;

storage {
    mapvec: StorageMapVec<u64, u64> = StorageMapVec {},
}

abi MyContract {
    #[storage(read, write)]
    fn push(key: u64, value: u64);

    #[storage(read)]
    fn get(key: u64, index: u64);
}

impl MyContract for Contract {
    #[storage(read, write)]
    fn push(key: u64, value: u64) {
        // this will push the value to the vec, which is accessible with the key
        storage.mapvec.push(key, value);
    }

    #[storage(read)]
    fn get(key: u64, index: u64) {
        // this will retrieve the vec at given key, and then retrieve the value at given index from that vec
        storage.mapvec.get(key, index)
    }
}