Suggestion: pull progress bar up into parent class

[IanMayo]

The progress bar is currently in the parser class.

It would remove a task from the parser-writer/maintainers if this was done in the parent class. We could do this by moving the loop-through-lines into the parent class, with the parser handling a single line at a time. If the parser needs the content from several lines (such as NMEA parser), the data would be stored in self variables.

Note: the parser would need a start method at the start of a new file to clear out the self variables.

Not all parsers parse line-by-line though. So, the XML parser would still have to work in the currently way, and not parse line-by-line.

[robintw]

I'm wondering whether this would actually make it more complicated for parser writers, particularly as we'd have to write it so that it was possible to get either one line at a time (for 'normal' parsers) or the whole file (for the XML parser, and any other parsers like that).

As an alternative, we could provide a function that they can use in the for loop which does the progress bar etc for us. So they would write something like:

for index, line in self.iterate_lines(file_object)

and the iterate_lines function would do the tqdm and enumerate calls, and provide the results using the yield keyword. For example:

def iterate_lines(self, file_object):
    for index, line in enumerate(tqdm(file_object.lines()), 1):
        yield index, line

How does that sound? It makes it easier for the user, but doesn't actually change the interface - so we don't have to support two ways of interacting with parsers.

[IanMayo]

XML yes - I was aware that this didn't iterate line by line.

I did imagine the client classes could override the parent at different levels, something like this:

Importer:
    def load_this_file:

    def _load_this_file:
       # loop through lines
       _load_this_line()

GPX Importer:
   # override file loader
   def _load_this_file:
      # include progress-bar

REP Importer
   # override line loader
   def _load_this_line: 

[robintw]

Fixed in #252