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Annotations

Annotations in k# are used to influence the compiler and optimizer.

note

If the goal is produce code, refers to macros.

Annotations go before the element who is going to be marked, using @annotationName

@sideEffect
log x = println x

Annotations​

sideEffect or impure​

Functions marked with this annotation has side effects, so calling this function is not guarantied return the same result

@sideEffect
log x = println x

@impure
random = rand
note

If a function a use a impure function b then a is impure.

tip

The @impure annotation is always calculated, this annotation is for documentation purposes, compiler always ignore the annotation.

pure​

Functions marked with this annotation has not side effects, so calling this function is guarantied return the same result

@pure
native sum a b
note

The @pure only applies for native functions. uses in other functions are ignored by the compiler

constant​

Functions marked with this annotation are considered constant values

@constant
native pi
note

The @constant only applies for native functions. uses in other functions are ignored by the compiler

name​

Used to define the name of the function, depending the target language

@name("round-value", for=["clojure"])
@name("RoundValue", for=["c#", "f#"])
roundValue value decimals = ...
Note

Compiler support different rules for function names depending the language.

doc​

Used to define documentation over types and functions

@doc("sum two numbers **using** ...")
specialSum a b = ...
Note

Documentation supports markdown syntax

if​

Instruct the compiler the function should compile only for target language

@if(["java", "c#"])
fn = ... //if target language is java or c# compiler compiles this function

Annotation value types supported​

The annotation values can be of the following types:

  1. String
  2. Number
  3. Boolean: true, false
  4. Annotation
  5. List of String, Number or Annotations

All values inside annotation should have a label, the first value could not have a label, in this case the label is default

@if(default=["java"])

// the same as

@if(["java"])
warning

If an annotation has the same label for a value, the las define value is used.

@if("java", "c#")

// is the  same as

@if("c#")