FsFlow.Builders.validate

The accumulating validate { } computation expression.

Remarks

Use this builder when you want to collect all validation failures instead of stopping at the first one. Use `and!` when sibling validations should accumulate into the same diagnostics graph. Plain `let!` and `do!` are sequential: if the left side fails, the later step is not evaluated. `Check<'value>` covers both value-preserving checks and gate checks. Use `Check.orError` to attach an application error, and `Guard.Of` / `Guard.MapError` when you want the same error-bound source shape to participate directly in validation. When nested API response fields need to keep their place in the diagnostics graph, use the scoped helpers `validate.key`, `validate.index`, and `validate.name` inside the computation expression. If you already have a `Validation` value, use `Validation.key`, `Validation.index`, or `Validation.name` to prefix it after the fact. It is intended for forms, configuration checks, and other input-heavy boundaries where the user benefits from seeing every problem at once.

Examples

 let validatedUser =
     validate {
         let! name = Check.notBlank input.Name
         let! age = Check.okIf (input.Age > 0) "Age must be positive"
         return { Name = name; Age = age }
     }

let validatedCustomer =
    validate.key "customer" {
        let! name =
            validate.name "Name" {
                return! input.Name |> Check.notBlank |> Check.orError "Name required"
            }

        return name
    }