https://github.com/ferranbt/heura

DSL to interact with Ethereum smart contracts
https://github.com/ferranbt/heura

blockchain dsl ethereum

Last synced: 10 days ago
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DSL to interact with Ethereum smart contracts

• Host: GitHub
• URL: https://github.com/ferranbt/heura
• Owner: ferranbt
• License: apache-2.0
• Created: 2018-11-05T10:58:38.000Z (about 6 years ago)
• Default Branch: develop
• Last Pushed: 2023-02-25T00:48:55.000Z (over 1 year ago)
• Last Synced: 2023-07-12T05:11:47.509Z (over 1 year ago)
• Topics: blockchain, dsl, ethereum
• Language: Go
• Homepage:
• Size: 109 KB
• Stars: 8
• Watchers: 2
• Forks: 0
• Open Issues: 6
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# Heura

Ethereum DSL to interact with smart contracts, call and listen for events.

## Install

```

go get github.com/umbracle/heura/heura

```

## Usage

Start the REPL:

```

go run main.go

```

Run a specific file:

```

go run main.go source.hra

```

By default, Heura uses the Infura mainnet nodes to make calls to contracts (https) and listen for events (websockets). Those values can be modified by setting the next flags:

```

go run main.go --endpoint  --wsendpoint  

```

## Syntax

Heura is an interpreted language. It is still a work in progress and the syntax is expected to change.

### Artifacts

Load artifacts from folder or files

```

artifact (

    "./abis",

    "./artifacts/0x.json"

)

```

or use the builtin ones:

```

artifacts (

    "ERC20"

)

```

### Calls

Once the artifact is loaded, you can instantiate contracts at specific addresses:

```

let token = ERC20(0x...)

```

or use ENS:

```

let token = ERC20("sometoken.eth")

```

After this, the call functions specified in the ABI are available:

```

token.decimals();

```

Transactions are not supported.

### Events

Listen for ethereum events:

```

on ERC20.Transfer (from, to, value) {

    print (from)

}

```

or filter for an specific address (with either the address or an ENS name):

```

on ERC20("somename.eth").Transfer (from, to, value)

```

Inside the scope of the event callback there is a special 'this' variable with information about the transaction that executed the event: blocknumber, blockhash, transaction hash and an instance of the contract that emit the event.

```

on ERC20.Transfer (from, to, value) {

    print (this.blocknumber)

    print (this.obj.symbol())

} 

```

It is possible to filter by specific topic values in the event:

```

let FROM=0xB9536d30A25466a909563EE4f35fE3c158fc2964

on ERC20.Transfer(from=FROM, to, value) {

```

Note that is only possible with parameters that are indexed on the event.

### Functions

Functions are declared with the keyword 'fn' and can return multiple values.

```

fn some_function() {

    return 1, 2

}

let x, y := some_function()

```

### Libraries

### Etherscan

Query a specific contract on Etherscan:

```

import "etherscan"

print(ens.Contract("0x..."))

```

Fetch ABIs from Etherscan:

```

import "etherscan"

let Contract = ens.Contract("0x")

on Contract.Transfer(from, to, value) {

}

```

### Ens

Resolve an ENS address:

```

import "ens"

print(ens.Resolve("address.eth"))

```