Type annotations for gleam/result

1 files changed, 16 insertions, 7 deletions

diff --git a/src/gleam/result.gleam b/src/gleam/result.gleam
index dce270c..28b7d96 100644
--- a/src/gleam/result.gleam
+++ b/src/gleam/result.gleam
@@ -1,49 +1,58 @@
 // Result represents the result of something that may succeed or fail.
 // `Ok` means it was successful, `Error` means it failed.
 
-pub fn is_ok(result) {
+pub fn is_ok(result: Result(a, e)) -> Bool {
   case result {
     Error(_) -> False
     Ok(_) -> True
   }
 }
 
-pub fn is_error(result) {
+pub fn is_error(result: Result(a, e)) -> Bool {
   case result {
     Ok(_) -> False
     Error(_) -> True
   }
 }
 
-pub fn map(result, with fun) {
+pub fn map(
+  over result: Result(a, e),
+  with fun: fn(a) -> b,
+) -> Result(b, e) {
   case result {
     Ok(x) -> Ok(fun(x))
     Error(e) -> Error(e)
   }
 }
 
-pub fn map_error(result, with fun) {
+pub fn map_error(
+  over result: Result(a, e),
+  with fun: fn(e) -> f,
+) -> Result(a, f) {
   case result {
     Ok(x) -> Ok(x)
     Error(error) -> Error(fun(error))
   }
 }
 
-pub fn flatten(result) {
+pub fn flatten(result: Result(Result(a, e), e)) -> Result(a, e) {
   case result {
     Ok(x) -> x
     Error(error) -> Error(error)
   }
 }
 
-pub fn then(result, apply fun) {
+pub fn then(
+  result: Result(a, e),
+  apply fun: fn(a) -> Result(b, e),
+) -> Result(b, e) {
   case result {
     Ok(x) -> fun(x)
     Error(e) -> Error(e)
   }
 }
 
-pub fn unwrap(result, or default) {
+pub fn unwrap(result: Result(a, e), or default: a) -> a {
   case result {
     Ok(v) -> v
     Error(_) -> default