Godot: All the Benefits of Implicit and Explicit Futures (Artefact)

Published in ECOOP, 2019

This artifact contains an implementation of data-flow futures in terms of control-flow futures, in the Scala language. In the implementation, we show microbenchmarks that solve the three identified problems from the paper:

  1. The Type Proliferation Problem,
  2. The Fulfilment Observation Problem, and
  3. The Future Proliferation Problem

There are also detailed instructions on design decisions that differ from the formal semantics and restrictions on the limits of how much can be encoded in the Scala language. We provide examples, e.g., creation of a proxy service using data-flow futures, as well as tests that exercise different parts of the type system.


This artifact shows an implementation of the formal semantics of data-flow futures, in terms of a library in the Scala programming language. It also show how far one can get encoding data-flow futures in terms of control-flow futures, and pinpoints the places that require modification of the compiler (or an advanced macro system).


The artifact package includes:

  • Documentation in files README.html, and README.pdf.
  • The Scala implementation of data-flow futures with tests and examples, in the Scala language (in folder godot).
  • An assets folder used by the README.html file.
  • A virtual machine GodotArtefact.ova that, under /home/vagrant/Desktop/Godot-Artifact/, contains the same files as mentioned above.\footnote{This has been done for ease of reading, so that a reader does not need to change between host and target machine when reading instructions.}

Getting the Artefact

The artefact endorsed by the Artifact Evaluation Committee is available free of charge on the Dagstuhl Research Online Publication Server (DROPS), and on github, https://github.com/kikofernandez/ecoop-artefact-godot.

Tested Platforms

The artifact disk image works on any platform running Oracle VirtualBox version 6.0.4 with 5 GiB of free disk space and 2 GiB of free RAM. The artifact also works on any machine that has the Scala compiler installed.


This artifact is provided under the MIT license.

MD5 sum of the Artefact


Size of the Artefact

2.94 GiB


We thank the reviewers of the artifact for their helpful comments.