veekun_pokedex/bin/edit-csv-as-yaml

#!/usr/bin/env python
"""Quick, dirty script that will convert a csv file to yaml, spawn an editor
for you to fiddle with it, then convert back to csv and replace the original
file.

Run me as: $0 some_file.csv

The editor used is $EDITOR, of course.

This script is not guaranteed to be even remotely reliable, so consider only
using it on files in source control.
"""

import codecs
import csv
import os
import subprocess
import sys
import tempfile

try:
    import yaml
except ImportError:
    sys.stderr.write("Please install PyYAML.\n")
    sys.exit(13)

# Try to use ordered dicts, so the YAML keys are in database table order
odict = dict  # fall back to regular dict
try:
    from collections import OrderedDict as odict
except ImportError:
    try:
        # This is a library for 2.4-2.6
        from ordereddict import OrderedDict as odict
    except ImportError:
        pass

# Tell PyYAML how to dump our ordered dict.
# The items() is to avoid the sorting the library does automatically.
# Needs to be added to SafeDumper manually, because we use safe_dump below, and
# every Representer class has its own independent goddamn dict of these things
from yaml.dumper import SafeDumper
yaml.add_representer(
    odict,
    lambda dumper, data: dumper.represent_dict(data.items()),
    Dumper=SafeDumper,
)

### Do actual work!
infilename, = sys.argv[1:]

data = []
with open(infilename) as infile:
    reader = csv.reader(infile, lineterminator='\n')
    column_names = [unicode(column) for column in next(reader)]

    # Read data...
    for row in reader:
        datum = odict()
        for col, value in zip(column_names, row):
            datum[col] = value.decode('utf-8')

        data.append(datum)


# Monkeypatch yaml to use > syntax for multiline text; easier to edit
from yaml.emitter import Emitter
orig_choose_scalar_style = Emitter.choose_scalar_style
def new_choose_scalar_style(self):
    if self.analysis is None:
        self.analysis = self.analyze_scalar(self.event.value)
    if self.analysis.multiline or len(self.analysis.scalar) > 80:
        return '>'
    return orig_choose_scalar_style(self)
Emitter.choose_scalar_style = new_choose_scalar_style

# Write to a tempfile
with tempfile.NamedTemporaryFile(suffix='.yml') as tmp:
    yaml.safe_dump(data, tmp,
        default_flow_style=False,
        allow_unicode=True,
        indent=4,
    )
    del data  # reclaim rams!

    error_line = ''  # used on errors
    while True:
        args = [os.environ['EDITOR'], tmp.name]
        if 'vim' in os.environ['EDITOR']:
            # vim has an arg for jumping to a line:
            args.append("+{0}".format(error_line))

        # Run the user's editor and wait for it to close
        subprocess.Popen(args).wait()
        tmp.seek(0)

        try:
            new_data = yaml.safe_load(tmp)
            break
        except yaml.YAMLError as e:
            if hasattr(e, 'problem_mark'):
                error_line = e.problem_mark.line + 1
            else:
                error_line = ''

            print
            print "Oh my god what have you done:"
            print
            print str(e)
            print
            print "Press Enter to try again, or I guess ctrl-c to bail."
            raw_input()

with open(infilename, 'wb') as outfile:
    writer = csv.writer(outfile, lineterminator='\n')
    writer.writerow([ column.encode('utf8') for column in column_names ])

    for datum in new_data:
        writer.writerow([
            datum[column].encode('utf8') for column in column_names
        ])