I was trying to use FluentValidation library in F Sharp sample. But I got stuck as I can't even turn a simple C Sharp code to F Sharp code.
But then I thought that this wonderful library is just trying to bring functional bits of programming side to CSharp, so instead of using this I should create my own library in FSharp only. That will be easy and appropriate way.
So, I need a opinion in that, which way will be better. And if someone can create FSharp sample for this, that will be great. It is just for learning purpose as I mostly use fluent library in C#. And I like to go with them in F#.
F# supports fluent DSLs, and there are several F# libraries with a fluent API. F#'s type system is a bit different from C#'s, and most of the differences pop-up with fluent APIs, but still, this works:
#r @"C:\Users\Ramon\Downloads\FluentValidation\FluentValidation\FluentValidation.dll"
open System
open FluentValidation
type Customer =
{ Surname : string
Forename : string
Company : string
Discout : int
Address : string
Postcode : string
Discount : int
HasDiscount : bool }
type IRuleBuilder<'T,'Property> with
member __.Ignore = ()
type CustomerValidator =
inherit AbstractValidator<Customer>
new () =
let beAValidPostcode postcode = true
base.RuleFor(fun customer -> customer.Surname).NotEmpty().Ignore
base.RuleFor(fun customer -> customer.Forename).NotEmpty().WithMessage("Please specify a first name").Ignore
base.RuleFor(fun customer -> customer.Company).NotNull().Ignore
base.RuleFor(fun customer -> customer.Discount).NotEqual(0).When(fun customer -> customer.HasDiscount).Ignore
base.RuleFor(fun customer -> customer.Address).Length(20, 250).Ignore
base.RuleFor(fun customer -> customer.Postcode).Must(beAValidPostcode).WithMessage("Please specify a valid postcode").Ignore
{ }
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