Add effect to read file (#27)

Author: ostcar

host/roc/roc.go

@@ -23,6 +23,7 @@ import (
 	"io"
 	"iter"
 	"net/http"
+	"os"
 	"sync"
 	"time"
 	"unsafe"
@@ -242,6 +243,16 @@ func roc_fx_get(url *RocStr) C.struct_ResultBytesString {
 	return getResultSuccess(body)
 }
 
+//export roc_fx_file_read_bytes
+func roc_fx_file_read_bytes(path *RocStr) C.struct_ResultBytesString {
+	content, err := os.ReadFile(path.String())
+	if err != nil {
+		return getResultError(err)
+	}
+
+	return getResultSuccess(content)
+}
+
 func getResultError(err error) C.struct_ResultBytesString {
 	errStr := NewRocStr(err.Error())
 	payload := *(*[24]byte)(unsafe.Pointer(&errStr))

platform/Host.roc

@@ -4,10 +4,12 @@ hosted Host
         stdout_line!,
         posix_time!,
         get!,
+        file_read_bytes!,
     ]
     imports []
 
 save_event! : List U8 => {}
 stdout_line! : Str => {}
 posix_time! : {} => U128
 get! : Str => Result (List U8) Str # TODO: Improve this
+file_read_bytes! : Str => Result (List U8) Str