1 files changed, 92 insertions, 0 deletions
diff --git a/src/gleam_stdlib.erl b/src/gleam_stdlib.erl
new file mode 100644
index 0000000..480518a
--- /dev/null
+++ b/src/gleam_stdlib.erl
@@ -0,0 +1,92 @@
+-module(gleam_stdlib).
+-include_lib("eunit/include/eunit.hrl").
+
+-export([expect_equal/2, expect_not_equal/2, expect_true/1, expect_false/1,
+         expect_is_ok/1, expect_is_error/1, atom_from_string/1,
+         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]).
+
+expect_equal(Actual, Expected) -> ?assertEqual(Expected, Actual).
+expect_not_equal(Actual, Expected) -> ?assertNotEqual(Expected, Actual).
+expect_true(A) -> ?assert(A).
+expect_false(A) -> ?assertNot(A).
+expect_is_ok(A) -> ?assertMatch({ok, _}, A).
+expect_is_error(A) -> ?assertMatch({error, _}, A).
+
+map_fetch(Map, Key) ->
+  case maps:find(Key, Map) of
+    error -> {error, nil};
+    OkFound -> OkFound
+  end.
+
+atom_create_from_string(S) ->
+  binary_to_atom(S, utf8).
+
+atom_to_string(S) ->
+  atom_to_binary(S, utf8).
+
+atom_from_string(S) ->
+  try {ok, binary_to_existing_atom(S, utf8)} catch
+    error:badarg -> {error, atom_not_loaded}
+  end.
+
+iodata_append(Iodata, String) -> [Iodata, String].
+iodata_prepend(Iodata, String) -> [String, Iodata].
+
+identity(X) -> X.
+
+decode_error_msg(Type, Data) ->
+  {error, iolist_to_binary(io_lib:format("Expected ~s, got `~p`", [Type, Data]))}.
+
+decode_atom(Data) when is_atom(Data) -> {ok, Data};
+decode_atom(Data) -> decode_error_msg("an Atom", Data).
+
+decode_string(Data) when is_binary(Data) -> {ok, Data};
+decode_string(Data) -> decode_error_msg("a String", Data).
+
+decode_int(Data) when is_integer(Data) -> {ok, Data};
+decode_int(Data) -> decode_error_msg("an Int", Data).
+
+decode_float(Data) when is_float(Data) -> {ok, Data};
+decode_float(Data) -> decode_error_msg("a Float", Data).
+
+decode_bool(Data) when is_boolean(Data) -> {ok, Data};
+decode_bool(Data) -> decode_error_msg("a Bool", Data).
+
+decode_thunk(Data) when is_function(Data, 0) -> {ok, Data};
+decode_thunk(Data) -> decode_error_msg("a zero arity function", Data).
+
+decode_pair(Data = {_, _}) -> {ok, Data};
+decode_pair(Data) -> decode_error_msg("a 2 element tuple", Data).
+
+decode_list(Data) when is_list(Data) -> {ok, Data};
+decode_list(Data) -> decode_error_msg("a List", Data).
+
+decode_field(Data, Key) ->
+  case Data of
+    #{Key := Value} ->
+      {ok, Value};
+
+    _ ->
+      decode_error_msg(io_lib:format("a map with key `~p`", [Key]), Data)
+  end.
+
+parse_int(String) ->
+  case string:to_integer(binary:bin_to_list(String)) of
+    {Integer, []} ->
+      {ok, Integer};
+
+    _ ->
+      {error, nil}
+  end.
+
+parse_float(String) ->
+  case string:to_float(binary:bin_to_list(String)) of
+    {Float, []} ->
+      {ok, Float};
+
+    _ ->
+      {error, parse_error}
+  end.