Implement string.compare/2

2 files changed, 15 insertions, 1 deletions

diff --git a/src/gleam/string.gleam b/src/gleam/string.gleam
index 9714220..9c5791c 100644
--- a/src/gleam/string.gleam
+++ b/src/gleam/string.gleam
@@ -1,5 +1,6 @@
 import gleam/iodata
 import gleam/list
+import gleam/order
 
 pub external fn length(String) -> Int = "string" "length"
 
@@ -7,6 +8,9 @@ pub external fn lowercase(String) -> String = "string" "lowercase"
 
 pub external fn uppercase(String) -> String = "string" "uppercase"
 
+pub external fn compare(String, String) -> order.Order =
+  "gleam_stdlib" "compare_strings"
+
 pub fn reverse(string) {
   string
   |> iodata.new
diff --git a/src/gleam_stdlib.erl b/src/gleam_stdlib.erl
index 3bb762d..03f26e6 100644
--- a/src/gleam_stdlib.erl
+++ b/src/gleam_stdlib.erl
@@ -6,7 +6,7 @@
          atom_create_from_string/1, atom_to_string/1, map_fetch/2,
          iodata_append/2, iodata_prepend/2, identity/1, decode_int/1,
          decode_string/1, decode_bool/1, decode_float/1, decode_thunk/1, decode_atom/1,
-         decode_pair/1, decode_list/1, decode_field/2, parse_int/1, parse_float/1]).
+         decode_pair/1, decode_list/1, decode_field/2, parse_int/1, parse_float/1, compare_strings/2]).
 
 expect_equal(Actual, Expected) -> ?assertEqual(Expected, Actual).
 expect_not_equal(Actual, Expected) -> ?assertNotEqual(Expected, Actual).
@@ -90,3 +90,13 @@ parse_float(String) ->
     _ ->
       {error, nil}
   end.
+
+compare_strings(Lhs, Rhs) ->
+  if
+    Lhs == Rhs ->
+      eq;
+    Lhs < Rhs ->
+      lt;
+    true ->
+     gt
+  end.