ConstraintTP

This project has been inspired from Dependent Type Provider

It provides compile-time constraints over basic F# types.

The goal would be to allow coders to create types according to specific rules and having value constraint over these rules at compile-time.

Rule system

The rule system is the following: We consider that each type could be shrinked down to a subset according to a specific rule. The rule would be written as a string representation of a function and would return the function itself. The type of the rule even though it is a string should, when evaluated by the fsi Session, be :

    'a -> bool

either the value given follows the rule (true) or not (false).

For instance, if one wants to define a type with all the integers multiple of 3, he would write :

    let [<Literal>] multiplesOf3Rule = "let f inputValue = inputValue % 3 = 0 \nf"

and would be called as a static parameter of ConstraintTP :

    type DivisibleBy3 = Constraint.Numbers.ConstraintInt32<Rule = multiplesOf3Rule>

What is supported so far

System of rule :

A system of rule that is quite generic and type safe through the pre-évaluation with the fsi session running behind the scene.

Basic F# types :

• sbyte
• byte
• uint16
• int16
• uint32
• int32
• uint64
• int64
• float32
• float

As a non-basic F# types :

• Arrays

   type: 'a []
  

I could do any non-basic F# types like lists... However I think that there are some aspect I should work on before going further.

TODO

---

• String with compile-time Regex verification as follow Type Foo = DependentType.String.Regex<".+@.+">

If one has some ideas regarding how we could take this TP to any direction please tell me, I would really appreciate.

Build process

run the following command :

.\build.cmd

Samples

Some basic samples could be found in Examples.fsx. You could also look at the slides I have prepared.