Round-trip parsing of data structure format (YAML or whatnot) preserving comments, for writing configuration

If you are using block structured YAML and Python is acceptable, youcan use the Python package¹ ruamel.yaml which is a derivative ofPyYAML and supports round trip preservation of comments:

import sysimport ruamel.yamlinp = """\# examplename:  # details  family: Smith   # very common  given: Alice    # one of the siblings"""yaml = ruamel.yaml.YAML()code = yaml.load(inp)code['name']['given'] = 'Bob'yaml.dump(code, sys.stdout)

with result:

# examplename:  # details  family: Smith   # very common  given: Bob      # one of the siblings

Note that the end-of-line comments are still aligned.

Instead of normal list and dict objects the code consists ofwrapped versions² on which the comments attached.

¹ _{Install with pip install ruamel.yaml. Works on Python 2.6/2.7/3.3+.Disclaimer: I am the author of that package.}
² _{ordereddict is used in case of a mapping, to preserve ordering}

Yeah, you and everyone who thought wow, yaml sounds cool, simply put, it doesn't exist, yet

update: you probably want to use Config::General, its apache config format (xmlish)

No, PPI is not general purpose tool, if you want BNF-ness, you want to use Marpa

Of all INI/JSON/YAML/XML, XML probably has the best editor support for non-programmers (sounds crazy)

One approach to this is using "lenses". See Augeas for one implementation.