Selang: an Smart Contract Programming Language for Ethereum: Introduction

After writing gelex (generic lexer), geast (generic Abstract Syntax Tree) and gepars (generic parser), using JavaScript as implementation language, I started to use these projects to design and build a simple programming language compiler: selang. As usual, I’m using TDD (Test-Driven Development) as code workflow. It helps me to follow KISS (keep-it-simple-stuped), baby steps, and emergent design.

The target of compilation is the Ethereum Virtual Machine. The process of compilation is:

Current implementation is still incomplete, but a sample with code, compilation, deploy and invocation is here.

The code of the simple contract is

You can compile the code with

And you can compile, deploy to http://localhost:8545 (usually a ganache-cli node instance), and invoke it, executing:

The only type supported is uint (unsigned 32 bytes integer). Next steps:

  • Support for other numeric types
  • Support for static and dynamic arrays (a bit challenging, memory management with bytecodes)
  • Support for strings (another challenge: using keccak256 hash functions to allocate dynamically the string in 32-bytes storage cells)
  • Constructor code (it’s code that is used only once, and should be compiled in different ways)
  • Inheritance

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Angel “Java” Lopez