Re: Next YAML: drop equality definition

On 3/6/16, Osamu TAKEUCHI <[email protected]> wrote:
> I agree duplicate key should be detected by
> YAML processors because we do not want users
> to use duplicate keys for overwriting the
> values of predefined keys.

By "predefined key" do you mean "a key previously defined in this map"?

Example 1: a statistics application wants to store a 'bunch' of
mappings, of data point name, to value;
in Java, if the YAML library uses a LinkedHashMap (as e.g. SnakeYaml
and I think at least one other Java library does) then the application
can simply serialize all these "histogram" pairs into a YAML map.

A list of maps could be used instead of a map. Knowing Java, this
feels more heavyweight than needed. Additional structure implies
storage and processing cost.


Example 2:
Let's say we have an intended to be user-edited config file.
The user enters duplicate key:value pairs in a YAML map.
The application:
- might be tolerant of this in some way,
- might want to transparently remove the duplicate,
- might want to log that this has happened,
- might want to be noisy about this e.g. "WARNING: Your config file
contains duplicate key/value pairs, namely "...", this violates the
config file schema - correct the error and re-start the application."
- might want to do other things ?

Transparently ignoring or flagging this 'error' takes away options
from the application - is it good to mandate this in the YAML spec, or
is it better to leave this to YAML library implementers?


> The key order in
> a YAML mapping should not have meaning.

Ack.

Preservation of key order by the YAML library can be a desirable
attribute for an application, and possibly desirable to be an option
in certain cases (max performance deserialization). (I am not (yet) a
YAML library implementer.)

------------------------------------------------------------------------------
Transform Data into Opportunity.
Accelerate data analysis in your applications with
Intel Data Analytics Acceleration Library.
Click to learn more.
http://makebettercode.com/inteldaal-eval