Type declarations

Types are declared inside type sections. Multiple types can be declared there.

Aliased types

Note that aliased types are the same, and not in any way incompatible with their original type.

type
  Age* = int  # `Age` is an alias for `int`

let 
  a: int = 10
  b: Age = 20
echo a + b

Distinct types

This provides type safety (not allowing to mix types):

type
  Age = distinct int
let 
  a: int = 10
  #b:Age  = 20 # ERROR
  b: Age = 20.Age
#echo a + b      # ERROR: type mismatch
#echo a.Age + b  # ERROR: type mismatch (sum operation does not exist for Age types)
echo a + b.int  # OK

???+ "hint" "borrow pragma This avoids having to create procedures for the operations related for the new types. For example:

proc `+` *(a, b: Age): Age {.borrow.}
proc `-` *(a, b: Age): Age {.borrow.}