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The Gren Programming Language

Frequently Asked Questions

Why is the language called Gren?

Gren is a norwegian word, meaning branch. This pays homage to both of Gren’s origins: Norway and Elm.

Why is Gren’s logo a bird?

The bird is a robin, which happens to be the name of Gren’s founder. The robin is placed within the G, which is meant to symbolize that it is sitting on a G(ren), which is the norwegian word for branch.

What is the relationship between Gren and Elm?

Gren started as a fork of Elm. This is mostly considered to be an implementation detail, a way to speed up initial development.

It’s not a goal of Gren to replace, or stay compatible in any way with, Elm.

What are the differences between Gren and Elm?

As of Gren 0.3.0, the main differences is that Gren has:

  • A git-based package manager. It’s slower, but has access to any github repo that you have, even private ones.
  • The default sequential data structure is an immutable array, not a linked list.
  • The default unit type is {}.
  • Extended support for pattern matching on records.
  • Any expression that returns a record can be used for record updates.
  • Multiline strings trim leading whitespace on each line.
  • Supports running on NodeJS.
  • No tuples. Check out this video on why tuples were removed.
  • No automatic constructors for type aliased records.
  • No GLSL syntax.
  • No reactor.
  • Sourcemap support for native integration with the JS debugger.

As of Gren 0.5.0 there are some more differences:

  • Some naming changes to make it more intuitive for people not used to functional programming. Like when..is instead of case..of and keepIf instead of filter.
  • Custom types are limited to 0 or 1 arguments. This is to prepare for the move to tagged values.
  • Support for more cross-platform browser and node APIs like web streams and web crypto.
  • No time traveling debugger.