lisette

package module
v0.2.7 Latest Latest
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 Go to latest Published: May 17, 2026 License: MIT Imports: 7 Imported by: 0

README

lisette/prelude

Types for Lisette, a language inspired by Rust that compiles to Go.

Type Description
Option[T] A value that is either present (Some) or absent (None). Replaces nilable pointers and comma-ok patterns.
Result[T, E] A value that is either a success (Ok) or a failure (Err). Replaces (T, error) return patterns.
Partial[T, E] A result that may carry both a value and an error (Ok, Err, or Both). For non-exclusive (T, error) returns.

Usage from Go

import lisette "github.com/ivov/lisette/prelude"

// Option
opt := lisette.MakeOptionSome(42)
opt.Is_some() // true
opt.Unwrap_or(0) // 42
none := lisette.MakeOptionNone[int]()
none.Unwrap_or(0) // 0

// Result
res := lisette.MakeResultOk[int, string](42)
res.Is_ok() // true
res.Unwrap_or(0) // 42

Learn more

By visiting the repository: github.com/ivov/lisette

Documentation

Overview

Package lisette provides core types for Lisette, a language inspired by Rust that compiles to Go.

For more information, visit https://lisette.run

Example (MapGet) 
package main

import (
	"fmt"

	lisette "github.com/ivov/lisette/prelude"
)

func main() {
	m := map[string]int{"alice": 100, "bob": 200}
	fmt.Println(lisette.MapGet(m, "alice"))
	fmt.Println(lisette.MapGet(m, "charlie"))
}

Output:
Some(100)
None

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

func ChannelClose 

func ChannelClose[T any](ch chan T)

func ChannelSend 

func ChannelSend[T any](ch chan T, value T) (sent bool)

func EnumeratedSliceFold 

func EnumeratedSliceFold[T any, U any](s []T, init U, f func(U, Tuple2[int, T]) U) U

func EnumeratedSliceMap 

func EnumeratedSliceMap[T any, U any](s []T, f func(Tuple2[int, T]) U) []U

func IsNilInterface added in v0.1.3 

func IsNilInterface(x any) bool

IsNilInterface reports whether an interface value is nil or contains a nil pointer (typed nil). Returns true for both cases.

func MapFrom 

func MapFrom[K comparable, V any](pairs []Tuple2[K, V]) map[K]V

func OptionMapOr 

func OptionMapOr[T any, U any](opt Option[T], def U, f func(T) U) U

func OptionMapOrElse 

func OptionMapOrElse[T any, U any](opt Option[T], def func() U, f func(T) U) U

func ResultMapOr 

func ResultMapOr[T any, U any, E any](res Result[T, E], def U, f func(T) U) U

func RuneAt added in v0.2.0 

func RuneAt(s string, i int) rune

RuneAt returns the rune at rune-index i in s. Panics on out-of-range i.

func SenderClose 

func SenderClose[T any](ch chan<- T)

func SenderSend 

func SenderSend[T any](ch chan<- T, value T) (sent bool)

func SliceAll 

func SliceAll[T any](s []T, f func(T) bool) bool

func SliceFilter 

func SliceFilter[T any](s []T, f func(T) bool) []T

func SliceFold 

func SliceFold[T any, U any](s []T, init U, f func(U, T) U) U

func SliceMap 

func SliceMap[T any, U any](s []T, f func(T) U) []U

func SliceToAny added in v0.1.14 

func SliceToAny[T any](s []T) []any

func Substring added in v0.2.0 

func Substring(s string, start, end int) string

Substring returns s[start:end] in rune indices. Panics on bad bounds.

func SubstringFrom added in v0.2.0 

func SubstringFrom(s string, start int) string

SubstringFrom returns s[start:] in rune indices. Panics on bad bounds.

func SubstringTo added in v0.2.0 

func SubstringTo(s string, end int) string

SubstringTo returns s[:end] in rune indices. Panics on bad bounds.

Types

type Option 

type Option[T any] struct {
	Tag     OptionTag
	SomeVal T
}
Example 
package main

import (
	"fmt"

	lisette "github.com/ivov/lisette/prelude"
)

func main() {
	some := lisette.MakeOptionSome(42)
	none := lisette.MakeOptionNone[int]()

	fmt.Println(some.IsSome())
	fmt.Println(none.IsNone())
	fmt.Println(some.UnwrapOr(0))
	fmt.Println(none.UnwrapOr(0))
}

Output:
true
true
42
0

func AssertType 

func AssertType[T any](value any) Option[T]

func ChannelReceive 

func ChannelReceive[T any](ch chan T) Option[T]

func EnumeratedSliceFind 

func EnumeratedSliceFind[T any](s []T, f func(Tuple2[int, T]) bool) Option[Tuple2[int, T]]

func MakeOptionNone 

func MakeOptionNone[T any]() Option[T]

func MakeOptionSome 

func MakeOptionSome[T any](arg T) Option[T]

func MapGet 

func MapGet[K comparable, V any](m map[K]V, key K) Option[V]

func OptionAndThen 

func OptionAndThen[T any, U any](opt Option[T], f func(T) Option[U]) Option[U]

func OptionFlatten 

func OptionFlatten[U any](opt Option[Option[U]]) Option[U]

func OptionFromCommaOk added in v0.1.20 

func OptionFromCommaOk[T any](val T, ok bool) Option[T]

OptionFromCommaOk wraps a Go comma-ok pair `(value, ok)` into an `Option[T]`.

func OptionFromNilable added in v0.1.20 

func OptionFromNilable[T any](val T, isNil bool) Option[T]

OptionFromNilable wraps a Go nilable `T` (pointer, function, interface, map, slice, channel) into an `Option[T]`.

func OptionFromPointer added in v0.1.25 

func OptionFromPointer[T any](ptr *T) Option[T]

OptionFromPointer wraps a Go `*T` into an `Option[T]`, dereferencing the pointer for the Some branch. Used when reading Go-imported struct fields declared `*T` (T value-typed) — the Lisette typedef is `Option<T>`.

func OptionMap 

func OptionMap[T any, U any](opt Option[T], f func(T) U) Option[U]
Example 
package main

import (
	"fmt"

	lisette "github.com/ivov/lisette/prelude"
)

func main() {
	opt := lisette.MakeOptionSome(21)
	doubled := lisette.OptionMap(opt, func(v int) int { return v * 2 })
	fmt.Println(doubled)
}

Output:
Some(42)

func OptionZip 

func OptionZip[T any, U any](opt Option[T], other Option[U]) Option[Tuple2[T, U]]

func ReceiverReceive 

func ReceiverReceive[T any](ch <-chan T) Option[T]

func SliceFind 

func SliceFind[T any](s []T, predicate func(T) bool) Option[T]

func SliceGet 

func SliceGet[T any](s []T, index int) Option[T]

func (Option[T]) Filter 

func (opt Option[T]) Filter(pred func(T) bool) Option[T]

func (Option[T]) IsNone 

func (opt Option[T]) IsNone() bool

func (Option[T]) IsSome 

func (opt Option[T]) IsSome() bool

func (Option[T]) IsZero 

func (opt Option[T]) IsZero() bool

func (Option[T]) MarshalJSON 

func (opt Option[T]) MarshalJSON() ([]byte, error)

func (Option[T]) OrElse 

func (opt Option[T]) OrElse(f func() Option[T]) Option[T]

func (*Option[T]) Scan added in v0.1.22 

func (opt *Option[T]) Scan(src any) error

func (Option[T]) String 

func (opt Option[T]) String() string

func (*Option[T]) Take 

func (opt *Option[T]) Take() Option[T]

func (*Option[T]) UnmarshalJSON 

func (opt *Option[T]) UnmarshalJSON(data []byte) error

func (Option[T]) UnwrapOr 

func (opt Option[T]) UnwrapOr(def T) T

func (Option[T]) UnwrapOrElse 

func (opt Option[T]) UnwrapOrElse(f func() T) T

func (Option[T]) Value added in v0.1.22 

func (opt Option[T]) Value() (driver.Value, error)

type OptionTag 

type OptionTag int
const (
	OptionSome OptionTag = iota
	OptionNone
)

type PanicValue 

type PanicValue struct {
	Value any
	Stack []byte
}

func (PanicValue) AsError 

func (p PanicValue) AsError() Option[error]

func (PanicValue) Message 

func (p PanicValue) Message() string

func (PanicValue) StackTrace 

func (p PanicValue) StackTrace() string

func (PanicValue) String 

func (p PanicValue) String() string

type Partial added in v0.1.3 

type Partial[T any, E any] struct {
	Tag    PartialTag
	OkVal  T
	ErrVal E
}

func MakePartialBoth added in v0.1.3 

func MakePartialBoth[T any, E any](val T, err E) Partial[T, E]

func MakePartialErr added in v0.1.3 

func MakePartialErr[T any, E any](arg E) Partial[T, E]

func MakePartialOk added in v0.1.3 

func MakePartialOk[T any, E any](arg T) Partial[T, E]

func PartialMap added in v0.1.3 

func PartialMap[T any, U any, E any](p Partial[T, E], f func(T) U) Partial[U, E]

func PartialMapErr added in v0.1.3 

func PartialMapErr[T any, E any, F any](p Partial[T, E], f func(E) F) Partial[T, F]

func (Partial[T, E]) Err added in v0.1.3 

func (p Partial[T, E]) Err() Option[E]

func (Partial[T, E]) IsBoth added in v0.1.3 

func (p Partial[T, E]) IsBoth() bool

func (Partial[T, E]) IsErr added in v0.1.3 

func (p Partial[T, E]) IsErr() bool

func (Partial[T, E]) IsOk added in v0.1.3 

func (p Partial[T, E]) IsOk() bool

func (Partial[T, E]) Ok added in v0.1.3 

func (p Partial[T, E]) Ok() Option[T]

func (Partial[T, E]) String added in v0.1.3 

func (p Partial[T, E]) String() string

func (Partial[T, E]) UnwrapOr added in v0.1.3 

func (p Partial[T, E]) UnwrapOr(def T) T

func (Partial[T, E]) UnwrapOrElse added in v0.1.3 

func (p Partial[T, E]) UnwrapOrElse(f func(E) T) T

type PartialTag added in v0.1.3 

type PartialTag int
const (
	PartialOk PartialTag = iota
	PartialErr
	PartialBoth
)

type Range 

type Range[T any] struct {
	Start T
	End   T
}

type RangeFrom 

type RangeFrom[T any] struct {
	Start T
}

type RangeInclusive 

type RangeInclusive[T any] struct {
	Start T
	End   T
}

type RangeTo 

type RangeTo[T any] struct {
	End T
}

type RangeToInclusive 

type RangeToInclusive[T any] struct {
	End T
}

type Result 

type Result[T any, E any] struct {
	Tag    ResultTag
	OkVal  T
	ErrVal E
}
Example 
package main

import (
	"fmt"

	lisette "github.com/ivov/lisette/prelude"
)

func main() {
	ok := lisette.MakeResultOk[int, string](42)
	err := lisette.MakeResultErr[int, string]("something went wrong")

	fmt.Println(ok.IsOk())
	fmt.Println(err.IsErr())
	fmt.Println(ok.UnwrapOr(0))
	fmt.Println(err.UnwrapOr(0))
}

Output:
true
true
42
0

func MakeResultErr 

func MakeResultErr[T any, E any](arg E) Result[T, E]

func MakeResultOk 

func MakeResultOk[T any, E any](arg T) Result[T, E]

func OptionOkOr 

func OptionOkOr[T any, E any](opt Option[T], err E) Result[T, E]

func OptionOkOrElse 

func OptionOkOrElse[T any, E any](opt Option[T], f func() E) Result[T, E]

func RecoverBlock 

func RecoverBlock[T any](f func() T) Result[T, PanicValue]

func ResultAndThen 

func ResultAndThen[T any, U any, E any](res Result[T, E], f func(T) Result[U, E]) Result[U, E]

func ResultMap 

func ResultMap[T any, U any, E any](res Result[T, E], f func(T) U) Result[U, E]

func ResultMapErr 

func ResultMapErr[T any, E any, F any](res Result[T, E], f func(E) F) Result[T, F]

func ResultOrElse 

func ResultOrElse[T any, E any, F any](res Result[T, E], f func(E) Result[T, F]) Result[T, F]

func (Result[T, E]) Err 

func (res Result[T, E]) Err() Option[E]

func (Result[T, E]) IsErr 

func (res Result[T, E]) IsErr() bool

func (Result[T, E]) IsOk 

func (res Result[T, E]) IsOk() bool

func (Result[T, E]) Ok 

func (res Result[T, E]) Ok() Option[T]

func (Result[T, E]) String 

func (res Result[T, E]) String() string

func (Result[T, E]) UnwrapOr 

func (res Result[T, E]) UnwrapOr(def T) T

func (Result[T, E]) UnwrapOrElse 

func (res Result[T, E]) UnwrapOrElse(f func(E) T) T

type ResultTag 

type ResultTag int
const (
	ResultOk ResultTag = iota
	ResultErr
)

type Tuple2 

type Tuple2[T any, U any] struct {
	First  T
	Second U
}

func ChannelSplit 

func ChannelSplit[T any](ch chan T) Tuple2[chan<- T, <-chan T]

func EnumeratedSliceFilter 

func EnumeratedSliceFilter[T any](s []T, f func(Tuple2[int, T]) bool) []Tuple2[int, T]

func MakeTuple2 

func MakeTuple2[T any, U any](first T, second U) Tuple2[T, U]

func (Tuple2[T, U]) String 

func (t Tuple2[T, U]) String() string

type Tuple3 

type Tuple3[T any, U any, V any] struct {
	First  T
	Second U
	Third  V
}

func MakeTuple3 

func MakeTuple3[T any, U any, V any](first T, second U, third V) Tuple3[T, U, V]

func (Tuple3[T, U, V]) String 

func (t Tuple3[T, U, V]) String() string

type Tuple4 

type Tuple4[T any, U any, V any, W any] struct {
	First  T
	Second U
	Third  V
	Fourth W
}

func MakeTuple4 

func MakeTuple4[T any, U any, V any, W any](first T, second U, third V, fourth W) Tuple4[T, U, V, W]

func (Tuple4[T, U, V, W]) String 

func (t Tuple4[T, U, V, W]) String() string

type Tuple5 

type Tuple5[T any, U any, V any, W any, X any] struct {
	First  T
	Second U
	Third  V
	Fourth W
	Fifth  X
}

func MakeTuple5 

func MakeTuple5[T any, U any, V any, W any, X any](first T, second U, third V, fourth W, fifth X) Tuple5[T, U, V, W, X]

func (Tuple5[T, U, V, W, X]) String 

func (t Tuple5[T, U, V, W, X]) String() string

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