initial commit

1 files changed, 15 insertions, 0 deletions

diff --git a/src/state.js b/src/state.js
new file mode 100644
index 0000000..8db6be4
--- /dev/null
+++ b/src/state.js
@@ -0,0 +1,15 @@
+import * as wrapper from "./wrapper.js"
+
+export const State = v => st => s => s(st)(v)
+
+export const get =         st => s => s(st)(st)
+export const put =  _st => st => s => s(_st)()
+export const modify = f => st => s => s(f(st))()
+
+export const fmap = f => g => st0 => g(st0)(st1 => a => s => s(st1)(f(a)))
+export const ap = f0 => x0 => st0 => f0(st0)(st1 => f1 => x0(st1)(st2 => x1 => s => s(st2)(f1(x1))))
+
+export const unit = State
+export const bind = run => f => s0 => run(s0)(s1 => v => f(v)(s1))
+
+export const DO = wrapper.DO(unit, bind)