When comparing Idris vs Red, the Slant community recommends Idris for most people. In the question“What are the best (productivity-enhancing, well-designed, and concise, rather than just popular or time-tested) programming languages?” Idris is ranked 29th while Red is ranked 57th. The most important reason people chose Idris is:
Idris not only has support for type classes, but is a fully dependently typed language, giving you the full power to statically verify your code.
Ranked in these QuestionsQuestion Ranking
Pros
Pro Full dependent types
Idris not only has support for type classes, but is a fully dependently typed language, giving you the full power to statically verify your code.
Pro Domain driven design and type driven development
Because of full dependent types in Idris, the programmer can focus more on modelling the domain with types and waste less time fixing common bugs that the type checker will catch. Dependent types help apply type driven development and a lot of code auto generation, making the compiler and type checker an ally in developing working software instead of just getting in the way.
Pro Simple toolchain
Other languages have complex, multi-step setups that beginners often get stuck on. Red has no installer, no setup, no dependencies*, just a single small (~1MB) command-line executable with both the compiler and repl. On Windows, you don't even have to launch executable from the command line--it has a GUI-console.
Pro Very simple syntax
Red syntax is a lot like Rebol. It's easier than most languages for beginners to pick up.
Pro Both low and high-level
Red has low enough access to do systems programming, but it's expressive enough for high-level scripting.
Pro Low cognitive load
Red has very simple syntax that's easy to learn. It gets out of your way and lets you think about the problem instead, enhancing productivity.
Cons
Con Not widely used
Con Not widely used
Con Weaker type inference
As type inference is undecidable for dependently-typed languages, Idris cannot offer the full type inference that Haskell supports, and so more type annotations will be needed.
Con Different semantics from Haskell
Idris, while similar to Haskell, has strict semantics, which may cause some confusion if your backend is done in Haskell. If using Idris, it would make sense to do the backend in Idris as well, if not for the fact that Idris currently has fewer libraries available for web development than Haskell.
Con Not production ready
Red is still under development and not considered stable.
Con Still in beta
It mostly works. It's good enough for building usable applications, but some planned features are missing.