WIP add Effect for a KV cache

.gitignore

@@ -15,4 +15,5 @@ examples/sleep
 examples/file
 examples/dir
 examples/env
-examples/command
+examples/command
+examples/cache

examples/cache.roc

@@ -0,0 +1,25 @@
+app "cache"
+    packages { pf: "../platform/main.roc" }
+    imports [
+        # pf.Stdout,
+        pf.Cache,
+        pf.Task.{ Task },
+        pf.Http.{ Request, Response },
+    ]
+    provides [main] to pf
+
+main : Request -> Task Response []
+main = \_ ->
+
+    key = 123
+    value = "The value is 123" |> Str.toUtf8
+
+    # Store value in cache
+    {} <- Cache.set key value |> Task.await
+
+    # Retrieve value from cache
+    result <- Cache.get key |> Task.attempt
+
+    when result is 
+        Ok bytes if bytes == value -> Task.ok { status: 200, headers: [], body: value }
+        _ -> Task.ok { status: 500, headers: [], body: Str.toUtf8 "Unable to retrieve value from cache"}

platform/Cache.roc

@@ -0,0 +1,15 @@
+interface Cache
+    exposes [get,set]
+    imports [Effect, InternalTask, Task.{ Task }]
+
+get : U64 -> Task (List U8) [NotFound]
+get = \key ->
+    Effect.getKV key
+    |> InternalTask.fromEffect
+
+
+set : U64, List U8 -> Task {} *
+set = \key, value ->
+    Effect.setKV key value
+    |> Effect.map Ok
+    |> InternalTask.fromEffect

platform/Effect.roc

@@ -33,6 +33,8 @@ hosted Effect
         sleepMillis,
         commandStatus,
         commandOutput,
+        getKV, 
+        setKV,
     ]
     imports [
         InternalHttp,
@@ -86,3 +88,7 @@ sleepMillis : U64 -> Effect {}
 
 commandStatus : Box InternalCommand.InternalCommand -> Effect (Result {} InternalCommand.InternalCommandErr)
 commandOutput : Box InternalCommand.InternalCommand -> Effect InternalCommand.InternalOutput
+
+# Cache
+getKV : U64 -> Effect (Result (List U8) InternalError.CacheError)
+setKV : U64, List U8 -> Effect {}

platform/InternalError.roc

@@ -1,12 +1,14 @@
 interface InternalError
-    exposes [InternalError, InternalDirReadErr, InternalDirDeleteErr]
+    exposes [InternalError, CacheError, InternalDirReadErr, InternalDirDeleteErr]
     imports [Path.{ Path }]
 
 InternalError : [
-    IOError Str, 
+    IOError Str,
     EOF,
 ]
 
+CacheError : [NotFound]
+
 InternalDirReadErr : [DirReadErr Path Str]
 
 InternalDirDeleteErr : [DirDeleteErr Path Str]

platform/glue-gen.sh

@@ -1,3 +1,7 @@
+#!/usr/bin/env bash
+
+# https://vaneyckt.io/posts/safer_bash_scripts_with_set_euxo_pipefail/
+set -euxo pipefail
 
 # Remove old glue flies
 rm -rf platform/src/glue

platform/main-manual-glue.roc

@@ -27,7 +27,8 @@ GlueTypes : [
     M InternalFile.WriteErr,
     N InternalError.InternalDirReadErr,
     O InternalError.InternalDirDeleteErr,
-    P InternalPath.UnwrappedPath,
+    P InternalError.CacheError,
+    Q InternalPath.UnwrappedPath,
 ]
 
 mainForHost : GlueTypes