1 files changed, 39 insertions, 0 deletions
diff --git a/std/Option.bruijn b/std/Option.bruijn
new file mode 100644
index 0000000..e33cbb5
--- /dev/null
+++ b/std/Option.bruijn
@@ -0,0 +1,39 @@
+# MIT License, Copyright (c) 2022 Marvin Borner
+
+:import std/Combinator .
+
+# empty option
+none T
+
+# encapsulates value in option
+some [[[0 2]]]
+
+# checks whether option is none
+none? [0 T [F]]
+:test none? none = T
+:test none? (some [[0]]) = F
+
+# checks whether option is some
+some? [0 F [T]]
+:test some? none = F
+:test some? (some [[0]]) = T
+
+# applies a function to the value in a option
+map [[0 none [some (2 0)]]]
+:test map [[1]] (some [[0]]) = some [[[0]]]
+:test map [[1]] none = none
+
+# applies a function to the value in a option or returns first arg if none
+map-or [[[0 2 1]]]
+:test map-or [[[2]]] [[1]] (some [[0]]) = [[[0]]]
+:test map-or [[[2]]] [[1]] none = [[[2]]]
+
+# extracts value from option or returns first argument if none
+unwrap-or [[0 1 I]]
+:test unwrap-or F (some T) = T
+:test unwrap-or F none = F
+
+# applies encapsulated value to given function
+apply [[1 none 0]]
+:test apply none [some ([[1]] 0)] = none
+:test apply (some [[0]]) [some ([[1]] 0)] = some [[[0]]]