aboutsummaryrefslogtreecommitdiff
path: root/src/Maybe.gleam
diff options
context:
space:
mode:
Diffstat (limited to 'src/Maybe.gleam')
-rw-r--r--src/Maybe.gleam52
1 files changed, 34 insertions, 18 deletions
diff --git a/src/Maybe.gleam b/src/Maybe.gleam
index a1790e1..57ba9af 100644
--- a/src/Maybe.gleam
+++ b/src/Maybe.gleam
@@ -2,61 +2,77 @@ module Maybe
exposing Maybe(..), is_just/1, is_nothing/1, map/2, flatten/1, flat_map/2,
unwrap/2
-type Maybe(x)
- = Just(x)
+type Maybe(x) =
+ | Just(x)
| Nothing
-fn is_just(maybe) =
- case maybe
+fn is_just(maybe) {
+ case maybe {
| Just(_) => True
| Nothing => False
+ }
+}
-test is_just() =
+test is_just() {
is_just(Just(1)) |> Assert.true
is_just(Nothing) |> Assert.false
+}
-fn is_nothing(maybe) =
- case maybe
+fn is_nothing(maybe) {
+ case maybe {
| Just(_) => False
| Nothing => True
+ }
+}
-test is_nothing() =
+test is_nothing() {
is_nothing(Just(1)) |> Assert.false
is_nothing(Nothing) |> Assert.true
+}
-fn map(maybe, fun) =
- case maybe
+fn map(maybe, fun) {
+ case maybe {
| Just(x) => fun(x)
| Nothing => Nothing
+ }
+}
-test map() =
+test map() {
map(Just(1), |x| x + 1) |> Assert.equal(_, Just(2))
map(Nothing, |x| x + 1) |> Assert.equal(Nothing)
+}
-fn flatten(maybe) =
+fn flatten(maybe) {
maybe
|> unwrap(_, Nothing)
+}
-test flatten() =
+test flatten() {
flatten(Just(Just(1))) |> Assert.equal(Just(1))
flatten(Just(Nothing)) |> Assert.equal(Nothing)
flatten(Nothing) |> Assert.equal(Nothing)
+}
-fn flat_map(maybe, fun) =
+fn flat_map(maybe, fun) {
maybe
|> map(_, fun)
|> flatten
+}
-test flat_map() =
+test flat_map() {
flat_map(Nothing, |x| Just(x + 1)) |> Assert.equal(Nothing)
flat_map(Just(1), |x| Just(x + 1)) |> Assert.equal(Just(2))
flat_map(Just(1), |_| Nothing) |> Assert.equal(Nothing)
+}
-fn unwrap(maybe, fallback) =
- case maybe
+fn unwrap(maybe, fallback) {
+ case maybe {
| Just(v) => v
| Nothing => fallback
+ }
+}
-test unwrap() =
+test unwrap() {
unwrap(Just(1), 50) |> Assert.equal(1)
unwrap(Nothing, 50) |> Assert.equal(50)
+}