arrays – How to Access Arrays from Public Struct Mapping in Solidity

arraysmappingstruct

I have this struct:

struct Amendment {
    string text;
    uint24 textColor;
    bool isRadialGradient;
    uint8[2] radialGradientCenterPct;
    uint16 linearGradientAngleDeg;
    uint24[2][11] gradientColors;
    uint messageId;
    uint inReplyToMessageId;
    address sender;
    address recipient;
    uint sentAt;
}

This mapping:

mapping(uint => Amendment) public amendmentMapping;

and this function:

function getAmendment(uint tokenId) public view returns (Amendment memory amendment) {
    return amendmentMapping[tokenId];
}

When I retrieve an Amendment via this function it works correctly. However, when I get an Amendment via the amendmentMapping directly the response does not include the arrays radialGradientCenterPct and gradientColors.

Ideally I would not have a separate getter, so I am curious whether this is a real limitation or whether I'm making a mistake.

Best Answer

It depends on your Solidity version, so sharing this might help. There are a couple questions with answers around this that might help:

Related Solutions

[Ethereum] mapping to a mapping? or mapping to a struct

This is how to use nested mappings and structs within a mapping.

Accesible through bookcase[--address--][--index--].books / bookcase[--address--][--index--].shelfId In real life you would make the second mapping an array though.

pragma solidity ^0.4.10;

contract Mappings {
    mapping(address => mapping(uint256 => Shelf)) bookcase;
    struct Shelf {
      bytes32[] books;
      uint shelfId;
    }
}

Solidity Structs – Accessing Mapping Inside Mapping of Struct in Solidity ^0.5.0

You can't do with a getter from public because the compiler doesn't (yet) know how to formulate the function with nested keys. I believe this is possible if you specific you wish to the experimental ABI.

A safer, more conventional workaround is to simple construct your own getter.

contract a { 

  struct Str {
    uint256 totalTokens;
    mapping(address => uint256) playerTokens;
  }

  mapping(uint256 => Str) private tokenStores;  // we'll make the getter manually

  function getPlayerToken(uint256 tokenId, address player) public returns(uint, uint) {
      Str storage t =  tokenStores[tokenId];
      return (t.totalTokens, t.playerTokens[player]);
  }
}

Hope it helps.

Best Answer

Related Solutions

[Ethereum] mapping to a mapping? or mapping to a struct

Solidity Structs – Accessing Mapping Inside Mapping of Struct in Solidity ^0.5.0

Related Topic