CODEWITHSUNDEEP
functional-programming
Suzan Cioc
Suzan Cioc

Reputation: 30097

Language with types as first-class values?

Is there a language, which is:

1) functional

2) has type inference

3) has currying

4) and has types as first-class values

also would like to compile from it to JVM and/or CLR

Upvotes: 9

Views: 803

Answers (4)

daniel gratzer
daniel gratzer

Reputation: 53881

I just started learning it but Coq might work for you.

It's quite possible to have a function which takes in a type (yes a raw type, not an instance of that type) and return another type (again, just the type, not an instance). If you're at all interested in formal verification of programs it's worth a look.

It also has the nice little benefit of being able to convert it's code to Haskell/OCaml/Scheme so that you can use their IO/Libraries since Coq tends lacks them.

It has type inference and currying but the type inference isn't perfect as the language's type system is well beyond (and more expressive than) a standard Milner-Hindley type system.

Upvotes: 7

J D
J D

Reputation: 48687

F# is functional and has type inference, currying and types as first-class values in the sense that you can dissect types at run-time via reflection. It compiles to the CLR and works well on Mono.

EXAMPLE: Taken from my (non-free) article Structural Typing in the F#.NET Journal:

The following createType function creates a new .NET assembly, new module and new public class type of the given name:

> let createType typeName =
    let name = System.Reflection.AssemblyName(Name="tmpAssembly")
    let run = System.Reflection.Emit.AssemblyBuilderAccess.Run
    let builder = System.Threading.Thread.GetDomain().DefineDynamicAssembly(name, run)
    let mdl = builder.DefineDynamicModule "tmpModule"
    let attrs = TypeAttributes.Public ||| TypeAttributes.Class
    mdl.DefineType(typeName, attrs);;
val createType : string -> TypeBuilder

Upvotes: 24

JJJ
JJJ

Reputation: 2791

Take a look at Scala, it works on both JVM and .NET. Here is some features including what you seek - http://www.scala-lang.org/node/104, look at "Scala is functional" section, "Local Type Inference", "Currying" and "Predefined function classOf" articles, also it has top type Any, pattern matching for values and types, reflect package.

Upvotes: 2

Mihai8
Mihai8

Reputation: 3147

First start from wikipedia type interference. Answer for this question seems to be Haskell or OCaml.

Upvotes: -1

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