When comparing APL vs Idris, 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 APL is ranked 51st. 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 High-level
No complicated loop processing to apply a function to a array of arrays. Functions are defined in a way that they will typically operate the same way on any number of array dimensions. This, along with the clear syntax, leads to very compact code that can be comprehended in a single line, rather than spread out over many pages.
Pro Iverson award in 2016
Pro Very concise
Pro Clear syntax
There is no operator precedence to memorize, as everything is evaluated right-to-left. E.g., in APL 3*10+3 = 39. You do have to type in some otherwise unusual characters, such as ↓ and ∊, but those are easy enough to pick up -- and they have the advantage of being easily remembered once understood, as they often have some connection to common mathematical symbols.
Pro Terse
You can seriously implement Conway's Game of Life in one line. There's a reason we do algebra with symbols instead of story problems. APL is good as a language of thought, since you can hold entire algorithms in your head at once.
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.
Cons
Con Hieroglyphics
APL symbols are only used by APL. You have to learn how to type them and how to read them. It doesn't work well with standard text editors , version control systems, search engines, or web forums. This makes it difficult for a beginner to find help.
Con Does not prepare you for most of the practical programming languages of today
While APL does have a strong use in certain areas (mostly mathematically intensive applications), it is a Domain-Specific language. That along with the fact that its syntax is not similar to C-like or other common syntax forms means that learning APL and expecting it to help you with learning other languages is like learning Calculus and expecting it to make English easier.
Con Write-only language
Maybe you can learn to read it with experience. And an interpreter. Reading APL is like reading a college math book. You might have to study a single line for fifteen minutes to understand what it's doing. And that's if you're an expert at APL. This also applies if you wrote it yourself more than a month ago. hopefully you have comments.
Con Flawless diamond
You can't extend the language itself. (J does this better.) Of course, what's built in is quite powerful.
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.