Is it possible to emit valid YAML with anchors / references disabled using Ruby or Python?

Question

Is it possible to disable creating anchors and references (and effectively list redundant data explicitly) either in PyYAML or Ruby's Psych engine?

Perhaps I missed something while searching the web, but it seems there are not many options available in Psych and I was not able to determine if PyYAML allows for that either.

The rationale is I have to serialize some data and pass it in a readable form to a not-really-technical co-worker for manual validation. Some data is redundant but I need it listed in a most explicit manner for readability (anchors and references are a nice concept for efficiency, but not for human-readability).

Ruby and Python are my tools of choice, but if there is some other reasonably simple way of 'unfolding' YAML documents, it might just do.

Answer 1

I found this related ticket on the PyYAML website (http://pyyaml.org/ticket/91), it looks like anchors can be disabled by using a custom dumper along the lines of:

import yaml

class ExplicitDumper(yaml.SafeDumper):
    """
    A dumper that will never emit aliases.
    """

    def ignore_aliases(self, data):
        return True

So, for example, the following outputs can be achieved using the standard dumper and the new explicit dumper:

>>> yaml.dump([1L, 1L])
"[&id001 !!python/long '1', *id001]\n"

>>> yaml.dump([1L, 1L], Dumper=ExplicitDumper)
'[1, 1]\n'

You can customise further properties to ensure pretty-printing etc. in the yaml.dump(...) call.