Fixed bug in #toMarkdown

Author: Joshua-Dias-Barreto

src/DataFrame/DataFrame.class.st

@@ -2408,7 +2408,9 @@ DataFrame >> toMarkdown [
 
 	columnWidths := dataFrame columnNames collect: [ :columnName |
 		                | maxWidth |
-		                maxWidth := columnName size.
+		                columnName isString
+			                ifFalse: [ maxWidth := columnName asString size ]
+			                ifTrue: [ maxWidth := columnName size ].
 		                dataFrame rows do: [ :row |
 			                | value |
 			                value := row at: columnName.
@@ -2417,7 +2419,10 @@ DataFrame >> toMarkdown [
 
 	dataFrame columnNames withIndexDo: [ :columnName :index |
 		| paddedColumnName |
-		paddedColumnName := columnName padRightTo: (columnWidths at: index).
+		paddedColumnName := (columnName isString
+			                     ifFalse: [ columnName asString ]
+			                     ifTrue: [ columnName ]) padRightTo:
+			                    (columnWidths at: index).
 		markdown nextPutAll: paddedColumnName , ' | ' ].
 	markdown cr.
 	markdown nextPutAll: '| '.