AeonLang 4.0.2b0

Language with Refinement Types

Aeon 4

Aeon is a programming languages that features Liquid Types, developed at the University of Lisbon. Unlike LiquidHaskell or LiquidJava, Aeon was designed from the ground up to have support for Liquid Types.

Aeon is in development, so assume all your programs to break. This 4th version is implemented as a Python interpreter, giving you access to any code written in Python.

Installation

Requirements:

• Uv

Usage

aeon can be executed directly from pypy using uvx:

uvx --from aeonlang aeon [file.ae]

Examples

Hello World

def main (args:Int) : Unit {
    print "Hello World"
}

The documentation is available at https://alcides.github.io/aeon.

Liquid Types

In this example, you can see the refined type {x:Int | x > 0} that represents all integers that are greater than 0. You can also see an example of Python FFI, where a python valid expression can be written as string and passed as the argument to the native function.

def sqrt : (i: {x:Int | x > 0} ) -> Float = native "__import__('math').sqrt";

def main (i:Int) : Unit {
    print (sqrt (-25)) # This is a type-checking error!
}

Authors

Aeon has been developed at LASIGE, University of Lisbon by:

• Alcides Fonseca
• Paulo Santos
• Eduardo Madeira
• Guilherme Espada
• Lishun Su
• Paulo Silva
• Diogo Sousa

Acknowledgements

This work was supported by Fundação para a Ciência e Tecnologia (FCT) through:

• the LASIGE Research Unit (ref. UID/00408/2025)
• the FCT Exploratory project RAP (EXPL/CCI-COM/1306/2021)
• the FCT Advanced Computing projects (CPCA/A1/395424/2021, CPCA/A1/5613/2020, CPCA/A2/6009/2020)

And by Lisboa2020, Compete2020 and FEDER through:

• the CMU|Portugal CAMELOT project (LISBOA-01-0247-FEDER-045915)

Publications

• Comparing the expressive power of Strongly-Typed and Grammar-Guided Genetic Programming at GECCO'23
• The Usability Argument for Refinement Typed Genetic Programming at PPSN'20

Let us know if your paper uses Aeon, to list it here.

Please cite as:

Fonseca, Alcides, Paulo Santos, and Sara Silva. "The usability argument for refinement typed genetic programming." International Conference on Parallel Problem Solving from Nature. Cham: Springer International Publishing, 2020.

Bibtex:

@inproceedings{fonseca2020usability,
  title={The usability argument for refinement typed genetic programming},
  author={Fonseca, Alcides and Santos, Paulo and Silva, Sara},
  booktitle={International Conference on Parallel Problem Solving from Nature},
  pages={18--32},
  year={2020},
  organization={Springer}
}