Build a type from a predicate — type

The escape hatch for anything the built-in types do not cover, without touching rdantic's internal problem format.

Usage

type_from(name, test, coerce = NULL, json = "string", scalar = FALSE)

Arguments

name: The type's name, shown in errors.
test: function(x) returning TRUE when x is acceptable.
coerce: Optional function(x) returning a converted value, tried only when test fails and rdantic.strict is off.
json: The JSON Schema type name.
scalar: Whether a length-1 value should serialise as a JSON scalar rather than a one-element array.

Value

A type.

Examples

hex <- type_from("hex", function(x) is.character(x) && all(grepl("^#[0-9a-f]{6}$", x)))
hex("#00ff99")
#> [1] "#00ff99"
try(hex("green"))
#> Error : 1 validation problem in hex
#>   <value>  expected hex, got chr[1] "green"

port <- type_from(
  "port",
  function(x) is.integer(x) && length(x) == 1 && x > 0 && x < 65536,
  coerce = function(x) as.integer(x),
  json = "integer",
  scalar = TRUE
)
port(8080)
#> [1] 8080