Yallo-lang

Yallo is a yet another high level experimental language for Tezos, with the purpose of providing a better abstraction for integrating different contracts.

Internally, the language is a functional language with side effects (storage assignments).

This is only a research project, it is not (yet) intendeed for real usage.

Usage

Yallo-lang compiler

  yallo.exe ACTION FILENAME

=== actions ===

  compile file.yallo [-dcontract ContractName] [-target ligo]
                 compiles a contract ContractName to ligo language

  extract-interface file.yallo -dcontract ContractName
                 extracts the yallo interface for the given contract

  interface-of-michelson file.tz
                 produce a yallo interface from michelson contract

=== flags ===

  [-contract _]        selected contract
  [-no-remove-unused]  disable removing unused symbols
  [-print-ast]         print ast
  [-print-ligo]        print ligo code
  [-print-pt]          print parse-tree
  [-target _]          target language
  [-verbose]           enable verbosity
  [-build-info]        print info about this build and exit
  [-version]           print the version of this build and exit
  [-help]              print this help text and exit
                       (alias: -?)

An example

We first define an interface describing the signature of a token contract, and another interface extending IToken with a getTotalSupply. (Views are entrypoint which receives as last argument 'a contract)

interface IToken {
    entry transfer(from: address, to: address, val: nat);
    view getBalance(ad: address): nat;
}

interface ITokenWithGetTotalSupply extends IToken {
    view getTotalSupply (): nat;
}

Now we can implement our token contract; the constructor is only an helper for building an initial storage value during compilation.

contract Token implements IToken {
    field balances: (address, nat) big_map;
    field totalSupply: nat;
    field symbol: string;

    constructor (owner: address, supply: nat, symbol: string) {
        this.balances = [ { owner: supply } ];
        this.totalSupply = supply;
        this.symbol = symbol;
    }

    entry transfer(from: address, to: address, val: nat) {
        let a: nat = this.balances.get(from, 0n);
        let b: nat = this.balances.get(to, 0n);
        assert (a >= val);
        this.balances.update(from, a - val);
        this.balances.update(to, b + val); 
        []
    }

    view getBalance(ad: address): nat {
        this.balances.get(ad, 0n)
    }
}

From another contract, if we want to use the token getBalance entry we'll do as follow:

import "IToken.yallo";

const tokenContractAddress: address = @KT1ThEdxfUcWUwqsdergy3QnbCWGHSUHeHJq;

contract usingAToken {
    field bal: nat;

    entry checkBalance(a: address) {
        [IToken.of(tokenContractAddress).getBalance(a, this.checkBalanceCallback)]
    }

    entry checkBalanceCallback(b: nat) {
        this.bal = b;
        []
    }
}

Or, if we want to deploy a token contract from another contract:

import "Token.yallo";

contract deployAToken {
    field tokenAddress: address;

    entry deployToken() {
        let (a: address, op: operation) = Tezos.createContract (Token(Tezos.selfAddress(), 100, "ourToken"), None, 0);
        this.tokenAddress = a;
        [op]
    }
}

License

Copyright (c) 2020 Davide Gessa

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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OTHER DEALINGS IN THE SOFTWARE.