5 files changed, 45 insertions, 0 deletions
diff --git a/stdlib/fs.ts b/stdlib/fs.ts
new file mode 100644
index 0000000..1374da5
--- /dev/null
+++ b/stdlib/fs.ts
@@ -0,0 +1,6 @@
+import { Effect } from './io'
+
+export interface WriteFile<_Path extends string, _Content extends string> extends Effect { }
+
+export interface ReadFile<_Path extends string> extends Effect<string> { }
+
diff --git a/stdlib/index.ts b/stdlib/index.ts
new file mode 100644
index 0000000..45197d9
--- /dev/null
+++ b/stdlib/index.ts
@@ -0,0 +1,4 @@
+export * from './io'
+export * from './fs'
+export * from './stdio'
+export * from './sys'
diff --git a/stdlib/io.ts b/stdlib/io.ts
new file mode 100644
index 0000000..c78204f
--- /dev/null
+++ b/stdlib/io.ts
@@ -0,0 +1,15 @@
+export interface Effect<T = unknown> { output: T }
+
+export interface Kind1<Inp = unknown, Out = unknown> {
+  input: Inp
+  return: Out
+}
+
+export interface Bind<_Eff extends Effect, _Fn extends Kind1> extends Effect { }
+
+export interface Seq<_Effs extends Effect[]> extends Effect { }
+
+export interface Do<_Effs extends Effect[]> extends Effect { }
+
+export interface DefineEffect<_Name extends string, _Func extends string> extends Effect { }
+
diff --git a/stdlib/stdio.ts b/stdlib/stdio.ts
new file mode 100644
index 0000000..365aead
--- /dev/null
+++ b/stdlib/stdio.ts
@@ -0,0 +1,12 @@
+import { Effect } from './io'
+
+export interface PutString<_ extends string> extends Effect { }
+
+export interface Print<_ extends any> extends Effect { }
+
+export interface Debug<_ extends string, T> extends Effect<T> { }
+
+export interface ReadLine extends Effect<string> { }
+
+export type PutStringLn<S extends string> = PutString<`${S}\n`>
+
diff --git a/stdlib/sys.ts b/stdlib/sys.ts
new file mode 100644
index 0000000..03541be
--- /dev/null
+++ b/stdlib/sys.ts
@@ -0,0 +1,8 @@
+import { Effect } from './io'
+
+export interface GetEnv<_Name extends string> extends Effect<string> { }
+
+export interface GetArgs extends Effect<string[]> { }
+
+export interface JsExpr<_Expr extends string> extends Effect<any> { }
+