feat(markdown): better error indicator

2 files changed, 17 insertions, 11 deletions

diff --git a/mardown/ast_modifier.go b/mardown/ast_modifier.go
index 93a5af3..36c6193 100644
--- a/mardown/ast_modifier.go
+++ b/mardown/ast_modifier.go
@@ -8,7 +8,7 @@ import (
 )
 
 var (
-	ErrInvalidModifier       = errors.Join(ErrInvalidParagraph, errors.New("invalid modifier organization"))
+	ErrInvalidUsage          = errors.Join(ErrInvalidParagraph, errors.New("invalid modifier usage"))
 	ErrInvalidTypeInModifier = errors.Join(ErrInvalidParagraph, errors.New("invalid type in modifier"))
 )
 
@@ -110,7 +110,7 @@ func modifier(lxs *lexers) (*astModifier, error) {
 		case lexerBreak:
 			lxs.Before() // because we did not use it
 			if len(s) != 0 {
-				return nil, ErrInvalidModifier
+				return nil, ErrInvalidUsage
 			}
 			return mod, nil
 		case lexerExternal:
@@ -128,7 +128,7 @@ func modifier(lxs *lexers) (*astModifier, error) {
 		}
 	}
 	if len(s) != 0 {
-		return nil, ErrInvalidModifier
+		return nil, ErrInvalidUsage
 	}
 	return mod, nil
 }
@@ -144,7 +144,7 @@ func modifierDetect(val string) (*astModifier, error) {
 	case 3:
 		mod.super = true
 	default:
-		return nil, ErrInvalidModifier
+		return nil, ErrInvalidUsage
 	}
 	return mod, nil
 }
diff --git a/mardown/error.go b/mardown/error.go
index bdcd9df..ad279fe 100644
--- a/mardown/error.go
+++ b/mardown/error.go
@@ -24,14 +24,20 @@ func (e *ParseError) Pretty() string {
 	ind := ""
 	for lxs.Next() && lxs.Current().Type != lexerBreak {
 		contxt += lxs.Current().Value
-		ln := len(lxs.Current().Value)
-		if lxs.current == current-1 {
-			ln--
-			ind += "^"
-		}
-		for range ln {
-			ind += "~"
+		if lxs.current <= current {
+			ch := "~"
+			if lxs.current == current {
+				ch = "^"
+			}
+			for range len(lxs.Current().Value) {
+				ind += ch
+			}
 		}
 	}
+	if lxs.current == current {
+		runes := []rune(ind)
+		runes[len(runes)-1] = '^'
+		ind = string(runes)
+	}
 	return fmt.Sprintf("%v\n\n%s\n%s", e, contxt, ind)
 }