Type for a typed function with a particular signature

Builds a type that accepts functions created by fn() only when their declared argument names, argument types, defaults, and return type match.

Usage

fn_type(...)

Arguments

...

Named argument types and an optional ~ type return declaration.

Value

A type.

Examples

int_mapper <- fn_type(x = int[1], ~ int[1])
int_mapper(fn(x = int[1], ~ int[1], { x + 1L }))
#> <fn> (x: int[1]) -> int[1]
try(int_mapper(fn(x = num[1], ~ num[1], { x + 1 })))
#> Error : 1 validation problem in <fn> (x: int[1]) -> int[1]
#>   <value>  expected <fn> (x: int[1]) -> int[1], got <fn> (x: num[1]) -> num[1]