48 lines
928 B
Go
48 lines
928 B
Go
package gonads
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import "errors"
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var (
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ErrOptionIsNone = errors.New("gonads: Option[T] has no value")
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)
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// Option is a container that might contain a value.
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type Option[T any] struct {
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val *T
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}
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// IsSome returns true if the Option has some value in it.
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func (o Option[T]) IsSome() bool {
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return o.val != nil
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}
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// IsNone returns true if the Option has no value in it.
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func (o Option[T]) IsNone() bool {
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return !o.IsSome()
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}
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// Take a value out of the option if it exists.
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func (o Option[T]) Take() (*T, error) {
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if o.IsNone() {
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return nil, ErrOptionIsNone
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}
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return o.val, nil
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}
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// Set the value of the option to a given value.
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func (o *Option[T]) Set(val T) {
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o.val = &val
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}
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// Clear removes the value from an Option.
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func (o *Option[T]) Clear() {
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o.val = nil
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}
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// NewOption creates a new Option with the given type. All Options
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// Start out as nil.
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func NewOption[T any]() *Option[T] {
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return &Option[T]{}
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}
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