KumaChan/support/examples/kmd/validator.km

# { "data": {"name":"Range", "version":"latest"} }
type Range protected {
    a: Integer,
    b: Integer
};

function @validate: &(Range) => Bool
    & {a, b} => (a <= b);

const Data1: String := 'KumaChan Data
{} ..Range latest
 a integer
  1
 b integer
  2';

const Data2: String := 'KumaChan Data
{} ..Range latest
 a integer
  3
 b integer
  2';

function describe-deserialized:
    &(String) => String
    &(data) =>
        switch { @deserialize { encode data } }.[Result[Range,Error]]:
        case Success range:
            let { a, b } := range,
            { "(?, ?)" (a.{String}, b.{String}) },
        case Failure err:
            err.{String},
        end;

do
    [{ describe-deserialized Data1 }, { describe-deserialized Data2 }]
        . { join \n }
        . { os::println }
        . { crash-on-error };