add feature: include line number in toc parse error message

pdftocio/tocparser.py

@@ -5,10 +5,10 @@
 
 from typing import IO, List
 from fitzutils import ToCEntry
-from itertools import takewhile
+from itertools import count, takewhile
 
 
-def parse_entry(entry: List) -> ToCEntry:
+def parse_entry(entry: List, nLine: int) -> ToCEntry:
     """parse a row in csv to a toc entry"""
 
     # a somewhat weird hack, csv reader would read spaces as an empty '', so we
@@ -24,7 +24,7 @@ def parse_entry(entry: List) -> ToCEntry:
         )
         return toc_entry
     except IndexError as e:
-        print(f"Unable to parse toc entry {entry};",
+        print(f"Unable to parse toc entry {entry} from line {nLine};",
               f"Need at least {indent + 2} parts but only have {len(entry)}.",
               "Make sure the page number is present.",
               file=sys.stderr)
@@ -35,4 +35,4 @@ def parse_toc(file: IO) -> List[ToCEntry]:
     """Parse a toc file to a list of toc entries"""
     reader = csv.reader(file, lineterminator='\n',
                         delimiter=' ', quoting=csv.QUOTE_NONNUMERIC)
-    return list(map(parse_entry, reader))
+    return list(map(parse_entry, reader, count(1)))