QSoC proposal: date_trunc supporting intervals

Hello!
Here is the text of my proposal which I've applied to GSoC.
(and link
https://docs.google.com/document/d/1vBjQzhFT_fgoIkoEP5TVeyFA6ggsYlLq76tghGVUD6A/edit?usp=sharing)
Any suggestions and comments are welcome.
Because I don't know the code of PostgreSQL well I decide not to
participate is QSoC with previous proposal (rewrite pg_dump and
pg_restore as libraries). But I'm very interested to participate in QSoC
2014 as a part of PostgreSQL. So It's my new proposal.

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PostgreSQL GSoC 2014 proposal

Project name

date_trunc() supporting intervals

Short description

The function date_trunc () is conceptually similar to the trunc function
for numbers. But now it doesn’t have full functionality because
intervals are not supporting intervals in date_trunc ().

Name: Alexander Shvidchenko

E-mail: askellio(at)gmail(dot)com <mailto:askellio(at)gmail(dot)com>

Location: Rostov-on-Don, Russia (UTC +04.00)

Benefits to the PostgreSQL Community

This feature will expand opportunities to work with time in databases.
It will do the job with time more flexible and easier.

Quantifiable results

Supporting and correct working with intervals by date_trunc ()

Project Schedule

until May 31

Make code review and solve architecture questions with help of community

1 June – 30 June

Detailed implementation of libraries.

1 July – 31 July

Finish Implementation of libraires and begin testing.

1 August -15 August

Final refactoring, testing and commit.

Some details

In the period until May 31 I need to discover what types of intervals
are able to be sent. Also I need to set the stamp of the result.

For example:

date_trunc (‘week’, ‘1 month 15 day’:interval)

result

‘1 month 14 day’

or

‘1 month 2 week’

It seems like this project idea isn’t very difficult and large. So if I
have time after finishing this job I’ll be able to work more: close some
bugs or realize some more features that will be usefull for the community.

Academic experience

I entered the university in 2013. Before entering the university I
finished the college in 2012. My graduate work in the college was the
client-server application. It was a realization of XMPP. The client was
realized in Qt. The client worked with SQLite database and the server
worked with MySQL database.

Why is PostgreSQL?

- I’m intereted in this idea and believe this project would be useful
for the community;

- PostgreSQL is a very respected community. I would be proud to be a
part of it;

- PostgreSQL is one of the best DBMS and I would like to make it better.

Links

1) PostgreSQL 9.3.3 Documentation, date_trunc

http://www.postgresql.org/docs/9.3/static/functions-datetime.html#FUNCTIONS-DATETIME-TRUNC

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With best wishes,
Alexander S.