stdlib: os package

Signed-off-by: Solomon Hykes <solomon@dagger.io>

stdlib/os/file.cue

@@ -0,0 +1,36 @@
+package os
+
+import (
+	"dagger.io/dagger"
+	"dagger.io/dagger/op"
+)
+
+// Built-in file implementation, using buildkit
+#File: {
+	from: dagger.#Artifact
+	path: string
+
+	read: {
+		// FIXME: support different data schemas for different formats
+		format: "string"
+		data: {
+			string
+			#up: [
+				op.#Load & {"from":   from},
+				op.#Export & {source: path, "format": format},
+			]
+		}
+	}
+
+	write: *null | {
+		// FIXME: support encoding in different formats
+		data: string
+		#up: [
+			op.#Load & {"from": from},
+			op.#WriteFile & {
+				dest:     path
+				contents: data
+			},
+		]
+	}
+}