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All you need to know for writing a reserve protocol collateral plugins quick start

core plugin depends on two plugin types:

  • Assets / Collateral (contracts/plugins/assets)
  • Trading (contract/plugins/trading) not discussed here

Collateral is erc20 token + below:

  • if ERC20 back ?
  • refresh()
  • rate exchange

Monetary units

  • Unit of Account
  • Target unit RToken maintaining stability or appreciation against its target unit
  • Reference unit

e.g. of 3 different tokens

  • Collateral : cUSDC
  • Refence : USDC
  • Target : USD

Units definition

  • {UoA} unit of account recommand USD here
  • {tok} whole token
  • {ref} whole reference token
  • {target} whole target unit
  • {ref/tok} refPerTok()
  • {target/ref} targetPerRef()
  • {UoA/target} pricePerTarget()

Basket definition

  • Prime basket this is set by governance , on changes through successful governance proposals. it consists of an array of triples e.g. :
  • Reference basket e.g. :
  • Collateral bascket e.g.:

IAsset interface

Image description

Accounting units

before we create a collateral plugin we have to choose 3 accounting units

Collateral unit

its just erc20 token

Reference unit

to be ask , what's a unit that this collateral token will always be worth the same value or more of .

Target unit

target unit has to do with a concept called the target basket. what's prime basket ?
A example of linear combination of target units:

  • 1 USD
  • 0.5 USD + 0.55 EURO
  • 0.5 USD + 0.35 EURO + 0.00001BTC

Unit of account

we can assume UoA == USD , because for now USD price are king.

Important properties for collateral plugins

Collateral plugins should be permisionless and should be able to used by any number if RTokens
Token balance can't be rebasing

refresh() should never be revert

refresh is been called before any transactions , it return exchange rates.
if occur an important error , refresh should change the state to DISABLED

strictPrice() price(bool) status()

the IFFY status should be temporary

Collateral must default if refPerTok() falls

Defaulted Collateral must stay defaulted

if status() ever returns disabled , then it must always return disabled in the nearly future

Token rewards should be claimable

  • rewardERC20()
  • getClaimCalldata()

Smaller Constraints

The value of the following methods should never change:

  • isColleteral()
  • targetName()
  • erc20()
  • rewardERC20()
  • erc20Deciamls()

Function-by-function walkthrough

  • strictPrice() {UoA/tok}
  • price(bool) {UoA/tok} if revert depends on the bool value true or false
  • refPerTok() {ref/tok}
  • targetPerRef() {target/ref}
  • pricePerTarget(){UoA/tartget}

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