1 files changed, 42 insertions, 3 deletions
diff --git a/compat/json/compat.go b/compat/json/compat.go
index 78a9d5f..b26914b 100644
--- a/compat/json/compat.go
+++ b/compat/json/compat.go
@@ -8,7 +8,9 @@ import (
 	"bufio"
 	"bytes"
 	"encoding/json"
+	"errors"
 	"io"
+	"strconv"
 
 	"git.lukeshu.com/go/lowmemjson"
 )
@@ -19,7 +21,7 @@ type (
 	RawMessage = json.RawMessage
 
 	// low-level decode errors
-	SyntaxError         = lowmemjson.SyntaxError
+	//SyntaxError         = lowmemjson.DecodeSyntaxError // expose a field
 	UnmarshalFieldError = json.UnmarshalFieldError
 	UnmarshalTypeError  = json.UnmarshalTypeError // lowmemjson.DecodeTypeError
 
@@ -28,7 +30,7 @@ type (
 
 	// marshal errors
 	InvalidUTF8Error      = json.InvalidUTF8Error
-	MarshalerError        = json.MarshalerError
+	MarshalerError        = lowmemjson.EncodeMethodError // expose a field
 	UnsupportedTypeError  = json.UnsupportedTypeError
 	UnsupportedValueError = json.UnsupportedValueError
 )
@@ -92,7 +94,7 @@ func Valid(data []byte) bool {
 }
 
 func Unmarshal(data []byte, ptr any) error {
-	return lowmemjson.Decode(bytes.NewReader(data), ptr)
+	return NewDecoder(bytes.NewReader(data)).Decode(ptr)
 }
 
 /////////////////////////////////////////////////////////////////////
@@ -113,6 +115,43 @@ func NewDecoder(r io.Reader) *Decoder {
 	}
 }
 
+func (dec *Decoder) Decode(ptr any) error {
+	err := dec.Decoder.Decode(ptr)
+	if derr, ok := err.(*lowmemjson.DecodeError); ok {
+		switch terr := derr.Err.(type) {
+		case *lowmemjson.DecodeSyntaxError:
+			err = &SyntaxError{
+				msg:    terr.Err.Error(),
+				Offset: terr.Offset,
+			}
+		case *lowmemjson.DecodeTypeError:
+			if typeErr, ok := terr.Err.(*json.UnmarshalTypeError); ok {
+				err = &UnmarshalTypeError{
+					Value:  typeErr.Value,
+					Type:   typeErr.Type,
+					Offset: typeErr.Offset,
+					Struct: derr.FieldParent,
+					Field:  derr.FieldName,
+				}
+			} else if _, isArgErr := terr.Err.(*lowmemjson.DecodeArgumentError); terr.Err != nil &&
+				!isArgErr &&
+				!errors.Is(terr.Err, strconv.ErrSyntax) &&
+				!errors.Is(terr.Err, strconv.ErrRange) {
+				err = terr.Err
+			} else {
+				err = &UnmarshalTypeError{
+					Value:  terr.JSONType,
+					Type:   terr.GoType,
+					Offset: terr.Offset,
+					Struct: derr.FieldParent,
+					Field:  derr.FieldName,
+				}
+			}
+		}
+	}
+	return err
+}
+
 func (dec *Decoder) Buffered() io.Reader {
 	dat, _ := dec.buf.Peek(dec.buf.Buffered())
 	return bytes.NewReader(dat)