open Reified
open Reified.Refinements
open Reified.Result
open Reified.Schema.Json

Field Blocks and Plain Functions

The inner field block is syntax for transforming one Schema<_> value. It prevents configuration for adjacent fields from joining into one pipeline.

field _.Email {
    withSchema Schema.text
    refine ContactEmail.refinement
    validate validateCompanyEmail
}

Its schema transformation is:

Schema.text
|> Schema.refine ContactEmail.refinement
|> Schema.validate validateCompanyEmail

The outer declaration then attaches that Schema<ContactEmail> to the "email" field and its getter.

withSchema

withSchema replaces canonical type resolution for this field:

field _.Children {
    withSchema (Schema.listWith childSchema)
}

There is no separate fieldWith declaration. Explicit schema selection is always an operation inside the field.

constrain

Portable constraints can be inspected by JSON Schema, documentation, and UI interpreters:

field _.Name {
    constraints [ present; maxLength 80 ]
}

The plain function is Schema.constrain.

refine

The plain function receives a descriptor explicitly:

let contactEmailSchema =
    Schema.text
    |> Schema.refine ContactEmail.refinement

Inside the field block, either supply the same value or use the destination type's canonical contribution:

field _.Email {
    withSchema Schema.text
    refine ContactEmail.refinement
}

type ContactEmail with
    static member Refinement(_: string, _: ContactEmail) = ContactEmail.refinement

field _.Email {
    withSchema Schema.text
    refine
}

The bare form uses the current string schema and the ContactEmail getter type as its compile-time dispatch key.

validate

Executable validation preserves the current type:

let companyEmailSchema =
    contactEmailSchema
    |> Schema.validate validateCompanyEmail

Inside the block:

field _.Email {
    validate validateCompanyEmail
}

Schema attaches the field path if the function fails. Arbitrary executable validation is not emitted as JSON Schema metadata; use a built-in constraint for facts other interpreters must read.