Future.Prelude

The prelude module holds proposal-driven extensions to the prelude, including
iterable helpers, option/result types, and attribute binding.

Values

let ZE_007

let ZE_007 = "https://zirric.knabel.dev/proposals/ZE-007-attribute-binding"

ZE-007: Attribute Binding.

let ZE_008

let ZE_008 = "https://zirric.knabel.dev/proposals/ZE-008-error-handling"

ZE-008: Error Handling.

let ZE_009

let ZE_009 = "https://zirric.knabel.dev/proposals/ZE-009-option-values"

ZE-009: Option Values.

let ZE_010

let ZE_010 = "https://zirric.knabel.dev/proposals/ZE-010-iterable"

ZE-010: Iterable.

Attributes

attr Bound

@Proposal(ZE_007)
attr Bound

A bound function of an attribute receives the targeted value as first argument.

Example:

attr Error {
  @Bound()
  @Returns(String)
  debug(err)
}

@Error({ err -> err.message })
data MessageError {
  @String message
}

MessageError("msg")[@Error].debug()

attr Countable

@Proposal(ZE_010)
attr Countable

Denotes that a type is countable and has a length.

Members:

• @Returns(Int) length(@Has(Countable) value)

attr Iterable

@Proposal(ZE_010)
attr Iterable

Marks a type as iterable. This allows using for ... <- ... on the type.

Members:

• iterate(@Has(Iterable) value, @Func yield)

attr Error

@Proposal(ZE_008)
attr Error

Marks a type as an error type.

Members:

• @Bound() @Returns(String) debug(err) — Returns a debug string representation
  of the error.

attr AnyResult

attr AnyResult

Marks a type as a result type. It is expected that types annotated with
@ResultType are unions. Marking a type with @AnyResult enables additional
syntactic sugar for working with result types:

• result!.value resolves to a Result with either Ok(value) or Err(error).
• result !! "default value" resolves to the value of Ok or the provided
  default value if Err.

attr OkType

@Proposal(ZE_008)
attr OkType

Provides a type hint for the Ok type of a Result.

Fields:

• @Type(AnyType) type — The type of Ok.value.

attr ErrType

@Proposal(ZE_008)
attr ErrType

Provides a type hint for the Err type of a Result.

Fields:

• @Type(AnyType) type — The type of Err.error.

attr AnyOption

attr AnyOption

Marks a type as an option type. It is expected that types annotated with
@Option are unions. Marking a type with @AnyOption enables additional
syntactic sugar for working with option types:

• option?.value resolves to an Option with either Some(value) or None.
• option ?? "default value" resolves to the value of Some or the provided
  default value if None.

attr SomeType

@Proposal(ZE_009)
attr SomeType

Provides a type hint for the Some type of an Option.

Fields:

• @Type(AnyType) type — The type of Some.value.

Data

data Range

@Proposal(ZE_010)
@Countable(_rangeCount)
@Iterable(_rangeIterate)
data Range

Represents an open range of integers from start (inclusive) to end (exclusive).
Can be created using the syntax start..<end.

Fields:

• @Int start
• @Int end

data ClosedRange

@Proposal(ZE_010)
@Countable(_rangeCount)
@Iterable(_rangeIterate)
data ClosedRange

Represents a closed range of integers from start (inclusive) to end (inclusive).
Can be created using the syntax start...end.

Fields:

• @Int start
• @Int end

data Ok

@Proposal(ZE_008)
data Ok

The successful result.

Fields:

• value — The value of the successful result.

data Err

@Proposal(ZE_008)
@Error({ err -> err.error.debug(err.error) })
data Err

The error result.

Fields:

• @Has(Error) error — The error of the result. Must a type annotated with
  @Error.

data Some

@Proposal(ZE_009)
data Some

The present value.

Fields:

• value — The value that is present.

data None

@Proposal(ZE_009)
data None

The absent value.

Union

union Result

@Proposal(ZE_008)
@AnyResult()
union Result

A result type that can be either Ok or Err. Used for functions that can fail.
The following syntactic sugar exists for working with Result types:

• result!.value
• result !! "default value"
• @String! which is equivalent to @Type(Result) @OkType(String)

Members:

• Ok
• Err

union Option

@Proposal(ZE_009)
union Option

An option type that can be either Some or None. Used for values that may or may
not be present. The following syntactic sugar exists for working with Option
types:

• option?.value
• option ?? "default value"
• @String? which is equivalent to @Type(Option) @SomeType(String)

Members:

• Some
• None

Functions

fn _arrayIterate

fn _arrayIterate(v, yield)

No documentation.

fn _dictIterate

fn _dictIterate(v, yield)

No documentation.

fn _stringIterate

fn _stringIterate(v, yield)

No documentation.

fn _rangeCount

fn _rangeCount(v)

No documentation.

fn _rangeIterate

fn _rangeIterate(v, yield)

No documentation.

fn _closedRangeCount

fn _closedRangeCount(v)

No documentation.

fn _closedRangeIterate

fn _closedRangeIterate(v, yield)

No documentation.