Repository F# setup
open Reified
open Reified.Refinements
open Reified.Result
One F# model for .NET and Fable JavaScript
Encode invariants once.
Enforce project wide.
Declare a rule once — on a value, a field, or a whole model — and the checking, the diagnostics, the JSON codec, the contract document, and the test data are all read from that one declaration.
type Signup = { Email: string; Age: int; Newsletter: bool }
let signupSchema =
schema<Signup> {
field _.Email { constraints [ present; email ] }
field _.Age { constrain (atLeast 13) }
field _.Newsletter
construct (fun email age newsletter ->
{ Email = email; Age = age; Newsletter = newsletter })
}
Schema.parse signupSchema input
// age: Expected a value at least 13, but was 11.
// email: Expected an email address, but was ada.
// newsletter: This value was omitted.
Json.serialize (Json.compile signupSchema) signup
// {"email":"ada@example.org","age":36,"newsletter":true}JsonSchema.generate signupSchema
// {"type":"object",
// "properties":{"email":{"type":"string"},
// "age":{"type":"integer","minimum":13},
// "newsletter":{"type":"boolean"}},
// "required":["email","age","newsletter"]}Every failure message, the JSON codec, the JSON Schema, and the generated test data come from that one declaration. Nothing above is written twice.
Choose your starting point
- Structured boundaries: Schema.
- Only need one piece? Choose Constraints, Refined, Parsing, or Data.
- Composing ordinary F# failures? Use Result handling independently.