Bond - Type-level validation for Scala

[Flavio W. Brasil]

https://github.com/fwbrasil/bond

I’ve just pushed to maven central the first release of Bond. It is a library to express validation constraints using the type system. Some usage examples:

import net.fwbrasil.bond._

case class Employee (
    name: String with NonEmpty,
    email: String with Email,
    age: Int with GreaterThan[T.`14`.T]
)

case class Company (
    employees: List[Employee] with MinSize[T.`2`.T]
)

val employeeAge: Int with GreaterThan[T.`14`.T] = ...

val lifted: Int with GreaterThan[T.`12`.T] =
    GreaterThan(12).lift(employee.age)

GreaterThan(18).lift(employee.age)

[error] The lifting of 'Int with net.fwbrasil.bond.GreaterThan[Int(14)]'' to 'net.fwbrasil.bond.GreaterThan[Int(18)]' is not valid (Bond)
[error]         GreaterThan(18).lift(employee.age)
[error]                             ^

Regards,

-- 

Flavio W. Brasil

http://fwbrasil.net

[Som Snytt]

Did anyone else just go, "James Bond."

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[Ben Hutchison]

Hi Flavio,

That looks really cool! I'm going to have a play with it when I find a suitable use case.

Some questions:

* The T.`12`.T syntax reads a bit odd. Is there any hope for a more natural way to write these constraint types?

* Will there by a Range or Interval type with bounds at both ends?

-Ben

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[Flavio W. Brasil]

Hi Ben,

On Wednesday, March 4, 2015 at 4:32 AM, Ben Hutchison wrote:

Hi Flavio,

That looks really cool! I'm going to have a play with it when I find a suitable use case.

Some questions:

* The T.`12`.T syntax reads a bit odd. Is there any hope for a more natural way to write these constraint types?

There is a SIP to provide a better mechanism, but I’m afraid no one is working on it right now:

https://github.com/adriaanm/scala/pull/12

If I understood correctly, this would be the syntax: `GreaterThan[10]`. 

* Will there by a Range or Interval type with bounds at both ends?

It isn’t supported, but it is possible to implement. Could you open a github issue if you’d like to have this feature?

Best,

 

-- 

Flavio W. Brasil