Define a schema field

Usage

field(
  name,
  description = name,
  type = c("string", "number", "integer", "boolean", "array"),
  enum = NULL,
  items = NULL,
  required = TRUE
)

Arguments

name: Optional Character: The name of the field.
description: Optional Character: A brief description of the field.
type: Character {"string", "number", "integer", "boolean", "array"}: The field type. A field cannot be an object, because it carries no properties; for an array of objects, set type = "array" and items = schema(...).
enum: Optional Character: Permitted values for this field. Only for type "string", "number" or "integer". Backends that support constrained decoding (e.g. Ollama) make any other value impossible rather than merely detectable.
items: Character, Field or Schema: What an array field contains. Required for type = "array" and forbidden otherwise. Give a type name ("string", "number", "integer", "boolean"), a field where the elements need their own description or enum, or a schema for an array of objects.
required: Logical: Whether the field is required.

Value

Field object

Author

EDG

Examples

# `type` defaults to "string", `required` defaults to TRUE
field("lab_name", "Name of the lab test")

#> lab_name: 
#>                  type: string
#>           description: Name of the lab test
#>                  enum: NULL
#>                 items: NULL
#>              required: TRUE
#>

field("normal_range_low", "Lower bound of normal range", type = "number")

#> normal_range_low: 
#>                          type: number
#>                   description: Lower bound of normal range
#>                          enum: NULL
#>                         items: NULL
#>                      required: TRUE
#>

field("flag", "Whether the result is out of range", enum = c("low", "normal", "high"))

#> flag: 
#>              type: string
#>       description: Whether the result is out of range
#>              enum: low, normal, high
#>             items: NULL
#>          required: TRUE
#>


# An array of strings: one element per item, so nothing has to be delimited
# inside a single string and later split back apart.
field("questions", "Each question, quoted as written", type = "array", items = "string")

#> questions: 
#>                   type: array
#>            description: Each question, quoted as written
#>                   enum: NULL
#>                  items: 
#>                         type: string
#>               required: TRUE
#>


# An array whose elements carry their own description
field(
  "codes", "ICD-10 codes found",
  type = "array",
  items = field("code", "One ICD-10 code, e.g. \"E11.9\"")
)

#> codes: 
#>               type: array
#>        description: ICD-10 codes found
#>               enum: NULL
#>              items: 
#>                            type: string
#>                     description: One ICD-10 code, e.g. "E11.9"
#>           required: TRUE
#>


# An array of objects
field(
  "results", "One row per lab result",
  type = "array",
  items = schema(
    "LabResult",
    field("name", "Test name"),
    field("value", "Result value", type = "number")
  )
)

#> results: 
#>                 type: array
#>          description: One row per lab result
#>                 enum: NULL
#>                items: 
#>                             type: object
#>                       properties: 
#>                                    name: 
#>                                                 type: string
#>                                          description: Test name
#>                                   value: 
#>                                                 type: number
#>                                          description: Result value
#>                         required: object of class 'AsIs'
#>             required: TRUE
#>