Add note about loupe functions

README.md

@@ -1,9 +1,11 @@
 # Diamond-3-Hardhat Implementation
 
-This is a simple example implementation for [EIP-2535 Diamond Standard](https://github.com/ethereum/EIPs/issues/2535). To learn about other implementations go here: https://github.com/mudgen/diamond
+This is an implementation for [EIP-2535 Diamond Standard](https://github.com/ethereum/EIPs/issues/2535). To learn about other implementations go here: https://github.com/mudgen/diamond
 
 The standard loupe functions have been gas-optimized in this implementation and can be called in on-chain transactions. However keep in mind that a diamond can have any number of functions and facets so it is still possible to get out-of-gas errors when calling loupe functions. Except for the `facetAddress` loupe function which has a fixed gas cost.
 
+**Note:** The loupe functions in DiamondLoupeFacet.sol MUST be added to a diamond and are required by the EIP-2535 Diamonds standard.
+
 ## Installation
 
 1. Clone this repo:

contracts/facets/DiamondCutFacet.sol

@@ -9,6 +9,9 @@ pragma solidity ^0.8.0;
 import { IDiamondCut } from "../interfaces/IDiamondCut.sol";
 import { LibDiamond } from "../libraries/LibDiamond.sol";
 
+// Remember to add the loupe functions from DiamondLoupeFacet to the diamond.
+// The loupe functions are required by the EIP2535 Diamonds standard
+
 contract DiamondCutFacet is IDiamondCut {
     /// @notice Add/replace/remove any number of functions and optionally execute
     ///         a function with delegatecall

contracts/facets/DiamondLoupeFacet.sol

@@ -9,6 +9,9 @@ import { LibDiamond } from  "../libraries/LibDiamond.sol";
 import { IDiamondLoupe } from "../interfaces/IDiamondLoupe.sol";
 import { IERC165 } from "../interfaces/IERC165.sol";
 
+// The functions in DiamondLoupeFacet MUST be added to a diamond.
+// The EIP-2535 Diamond standard requires these functions.
+
 contract DiamondLoupeFacet is IDiamondLoupe, IERC165 {
     // Diamond Loupe Functions
     ////////////////////////////////////////////////////////////////////

contracts/libraries/LibDiamond.sol

@@ -7,6 +7,9 @@ pragma solidity ^0.8.0;
 /******************************************************************************/
 import { IDiamondCut } from "../interfaces/IDiamondCut.sol";
 
+// Remember to add the loupe functions from DiamondLoupeFacet to the diamond.
+// The loupe functions are required by the EIP2535 Diamonds standard
+
 library LibDiamond {
     bytes32 constant DIAMOND_STORAGE_POSITION = keccak256("diamond.standard.diamond.storage");