diff options
Diffstat (limited to 'modules/optional/option.go')
| -rw-r--r-- | modules/optional/option.go | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/modules/optional/option.go b/modules/optional/option.go index ccbad259c2..cbecf86987 100644 --- a/modules/optional/option.go +++ b/modules/optional/option.go @@ -5,6 +5,12 @@ package optional import "strconv" +// Option is a generic type that can hold a value of type T or be empty (None). +// +// It must use the slice type to work with "chi" form values binding: +// * non-existing value are represented as an empty slice (None) +// * existing value is represented as a slice with one element (Some) +// * multiple values are represented as a slice with multiple elements (Some), the Value is the first element (not well-defined in this case) type Option[T any] []T func None[T any]() Option[T] { @@ -22,6 +28,13 @@ func FromPtr[T any](v *T) Option[T] { return Some(*v) } +func FromMapLookup[K comparable, V any](m map[K]V, k K) Option[V] { + if v, ok := m[k]; ok { + return Some(v) + } + return None[V]() +} + func FromNonDefault[T comparable](v T) Option[T] { var zero T if v == zero { |