Astropy Proposal for Enhancement 6: Enhanced Character Separated Values table format (APE 6)

Data tables in astronomical analysis frequently contain additional metadata beyond just the column names and data values.  Common attributes include the numerical data type, the physical unit, and a longer textual description of the column content.  These attributes can be reprented in binary formats such as FITS, but the available options for a text-only format are inadequate.

APE6 proposes to fill this void by specification of a standard for the interchange of tabular data in a text-only format.  The format handles the key issue of serializing column specifications and table metadata by using a YAML-encoded data structure.  The actual tabular data are stored in a standard character separated values (CSV) format, giving compatibility with a wide variety of non-specialized CSV table readers.

Using YAML makes it extremely easy for applications *and humans* to read both the standardized data format elements (e.g. column name, type, description) as well as complex metadata structures.  YAML also lends itself to simple table modifications by humans in a plain text editor.

The reference Python implementation in ``astropy.io.ascii`` is relatively straightforward and will provide a significant benefit of allowing text serialization of most astropy Table objects, persistent storage, and subsequent interchange with other users.

Although developed in the context of Astropy, there is nothing astronomy-specific in this format and it could be useful for other domains or languages.  However, promoting that is beyond the scope of this APE.