/home/ofey

Encounters with LISP

2006-03-19T14:36:00.000-08:00

Ever since I read The Cathedral and the Bazaar , I've wanted to try out some Lisp.

LISP is worth learning for a different reason — the profound enlightenment experience you will have when you finally get it. That experience will make you a better programmer for the rest of your days, even if you never actually use LISP itself a lot. -- Eric S. Raymond

But the trouble with most LISP tutorials out there is that they just don't make it easy to get into the flow of this language. Not anymore for me; I found the best LISP book available online.Common Lisp: A Gentle Introduction to Symbolic Computation

So far I've just browsed through the book without writing much code. The favourite chapter so far has been Chapter 7: Applicative Programming. I can say I finally get it, what map and reduce are all about. The curiosity that's been bothering me ever since that Google paper (MapReduce:Simplified Data Processing on Large Clusters (PDF Alert!!))

Well, I've used map quite a bit in Perl. But never got to use reduce. Looks like List::Util module is the best way to try it out.

I don't think I'll ever write much in LISP. But just reading LISP code so far has been fun and educational.

Mini Languages and Perl 5

2006-03-12T16:59:00.000-08:00

I must've been really sleeping under a rock. It took too long but finally encountered Parse::RecDescent

Feels one step closer to trying out my own mini-language.

And things should get easier in Perl 6 because grammars are default in there.

Gtk2::Ex::DBITableFilter

2005-09-27T13:22:00.000-07:00

The buttons and the progressbar come standard with the widget. The progressbar updates during record-fetching.

Note the excel-like drop down filter boxes in the second image.

If you want to know more about it, then go to http://search.cpan.org/~ofeyaikon/Gtk2-Ex-DBITableFilter/

2005-06-07T22:42:00.000-07:00

gtk2-perl-source-1.061

This nice looking picture is a treemap of the Gtk2-Perl source (1.061 version). This treemap was generated using my brand-new Gtk2::Ex::TreeMap module (Find the latest version here.)

If you want to know more about treemaps, try one of the following sites.

http://www.cs.umd.edu/hcil/treemap/
http://www.marumushi.com/apps/newsmap/newsmap.cfm
http://codecubed.com/map.html the del.icio.us most popular treemap
http://www.smartmoney.com/marketmap/

Gtk2::Ex::ICal::Recur

2005-04-13T22:47:00.000-07:00

Gtk2-Ex-ICal-Recur

Gtk2::Ex::RecordsFilter

2005-02-25T13:24:00.000-08:00

Gtk2::Ex::RecordsFilter - A high level widget to browse reasonably large amounts of relational data and select a subset of records. This widget is inspired by the song browser of iTunes.

SYNOPSIS

use Gtk2 -init;
use Gtk2::Ex::RecordsFilter;

# Create a recordset
my $recordset = [
[Automobiles,Cars,Toyota,Camry],
[Automobiles,SUV,BMW,Xi],
[Automobiles,SUV,Toyota,Highlander],
[Automobiles,Cars,Mitsubishi,Lancer]
];

# Create the recordsfilter object
my $recordsfilter = Gtk2::Ex::RecordsFilter->new;

# Specify the headers for the columns
my $headers = ['Category', 'Sub-Category', 'Brand', 'Model'];
Gtk2::Ex::RecordsFilter->set_headers($headers);

# Inject data into the widget
Gtk2::Ex::RecordsFilter->set_data($recordset);

# Get a ref to its widget
my $recordsfilter_widget = $recordsfilter->get_widget();

# Create the root window
my $window = Gtk2::Window->new;
$window->signal_connect(destroy => sub { Gtk2->main_quit; });
$window->set_default_size(500, 300);

# Add the widget to the root window
$window->add($recordsfilter_widget);
$window->show_all;

Gtk2->main;

DESCRIPTION

When working with large amounts of relational records (csv files, database records, music files index), a common task is to filter out a subset or records from a given set. For example, in a master-detail database design, the master recordset, which is typically smaller than the detail recordset, can be filtered out and the filtered subset of master records can then be used to perform additional tasks on the detail records that they point to.

A common example of this usage is the song browser in your own mp3 player application (for example, the iTunes application). This application will allow you to choose an mp3 file (the detail record) based on criteria such as Artist, Album, Song (the master record). Once the master record is choosen (i.e., the Artist, Album and Song) it then performs a task on the detail record (i.e., play the mp3 file).

This Gtk2::Ex::RecordsFilter widget is inspired by the iTunes song browser widget. But this widget carries certain functionality which is not present in the iTunes song browser. The iTunes song browser allows the user to choose one song (one master record) at a time and play it. However, a more general usage should allow the user to choose multiple master records at a time. One approach for such multiple selections is to enable the user to click on different records with the CTRL key pressed and then choose all the highlighted records in one shot. This widget takes a different approach, which I call the 'shopping cart' approach. This is explained in the next section.

USER INTERACTION
The top half the widget shows all the master records. The records are shown in a hierarchical fashion similar to the iTunes song browser. Clicking on a parent node on the left-most box will cause all the boxes on its right to show only the child nodes.

The user can click on any entry in the top half and then click on the add to selection button and the record will show up in the bottom half. If the entry clicked is in one of the left boxes, then the widget automatically discovers all the child nodes and adds them to the selection. Upon adding to selection, the record is removed from the top half and shows up in the bottom half. The remove from selection button works in the reverse way.

The user can click on multiple records in the top half using the CTRL key.

METHODS

Gtk2::Ex::RecordsFilter->new

my $recordsfilter = Gtk2::Ex::RecordsFilter->new;

The widget can be used to select a subset of these records (into a selection list). The methods get_selected_rows and get_unselected_rows can be used to view the selection ( or unselection) at any point.

'Selected' portion is referred to as the 'RIGHT' side (bottom). 'Unselected' portion is referred to as the 'LEFT' side (top)

Gtk2::Ex::RecordsFilter->set_data

$recordsfilter->set_data($recordset);

The recordset is injected into the widget using this method. The widget will automatically create the HPaned children and the Selection buttons.

Gtk2::Ex::RecordsFilter->get_widget

my $recordsfilter_widget = $recordsfilter->get_widget();

This method returns the widget of the filter object.

Gtk2::Ex::RecordsFilter->get_selected_rows

my $selected_rows = $recordsfilter->get_selected_rows();
print Dumper $selected_rows;

This method returns the selected_rows contained in the bottom half of filter widget. A common usage is to have an Apply button which, when clicked, will invoke this method and use the returned results. Check out the examples directory to see this in action.

$apply_button->signal_connect (clicked =>
sub {
  my $selected_rows = $recordsfilter->get_selected_rows();
  print Dumper $selected_rows;
}
);

Gtk2::Ex::RecordsFilter->get_unselected_rows

my $selected_rows = $recordsfilter->get_unselected_rows();
print Dumper $selected_rows;

This method returns the unselected_rows contained in the top half of filter widget. This method too can be used with an Apply button like the one shown above.

Gtk2::Ex::TreeMaker - 0.07

2005-02-11T15:21:00.000-08:00

This is the 0.07 release of this widget. See here for details on the widget including a screenshot

CHANGES

Added two more signals (cell-enter and cell-leave)
These signals are applicable only for the 'hyperlinked' cells. Call-back will be called when the mouse enters or leaves a 'hyperlinked' cell.
Updated the example to reflect the new capability
Updated the documentation to reflect the new capability

Gtk2::Ex::TreeMaker - 0.06

2005-02-08T23:12:00.000-08:00

This is the 0.06 release of this widget. See here for details on the widget including a screenshot

CHANGES

Fixed the issue with the Makefile.pl
Added tests (40 of them) to verify the model that is being created
(Still to add tests for the UI events, cell-edited, cell-clicked etc)
Cleaned up the API for setting the column_names.

Gtk2::Ex::TreeMaker - 0.05

2005-02-04T15:15:00.000-08:00

This is the 0.05 release of this widget. See here for details on the widget including a screenshot

CHANGES

Added a custom attribute called 'hyperlinked'. The mouse pointer changes when moved over a 'hyperlinked' cell. A specified call-back is called when the cell is clicked.
In addition to this custom attribute, any of the attributes of the Gtk2::CellRendererText can also be passed to this widget. (background, editable etc)
Added signal handler for 'cell-clicked', 'cell-edited'. Cleaned up the code defining the signal_connect.
Cleaned up code in other areas too.
Updated documentation.
Updated the MANIFEST to include the /examples.

Gtk2::Ex::TreeMaker

2005-02-02T18:42:00.000-08:00

Gtk2::Ex::TreeMaker - A high level widget to represent a set of relational records in a hierarchical spreadsheet kinda display. This task is typical to most of the business application user interfaces.

Description
Typically in business applications, users like to view data in a spreadsheet kind of display. (Columns represent timeline (typically) and rows represent measures like sales/inventory/blah/blah).

The data itself is typically stored internally as relational records. For example, here is some sales info (stored internally in a relational database)

-------------------------------------

Region, City, Product, Date, Quantity

-------------------------------------

Texas, Dallas, Fruits, Dec-2003, 300

Texas, Dallas, Veggies, Jan-2004, 120

Texas, Austin, Fruits, Nov-2003, 310

Texas, Austin, Veggies, Feb-2004, 20

-------------------------------------

The user will typically want to view the same data in a hierarchical (/spreadsheet) kinda display.

------------------------------------------------------

Prod / Date   Nov-2003  Dec-2003  Jan-2004  Feb-2004

------------------------------------------------------

Texas

Dallas

  Fruits                  300       

  Veggies                           120

Austin

  Fruits        310

  Veggies                                     20

------------------------------------------------------

With web-based business apps, similar views are created in the browser using lots of html/jsp coding.

The Gtk2::TreeView is an excellent widget to display a similar presentation of data in a desktop app. But creating a (hierarchical) TreeView from flat relational data can require some recursive function coding. It would be great if all this recursive code could be abstracted out and packaged separately.

This high level widget is designed with that purpose in mind. This module will accept a relational feed of records and automatically convert it into a hierarchical treeview using the Gtk2::TreeView. The process involves invoking some recursive functions to build a TreeModel and populate it. Also, since the spreadsheet itself can be rather long horizontally, the widget also has a FreezePane capability.

The above screenshot was generated using the following relational data (csv)

__DATA__

#state,city,product,date,text,editable,underline,background

Texas,Dallas,Fruits,Dec-2003,300,0,1,red

Texas,Dallas,Veggies,Jan-2004,120,1,0,blue

Texas,Austin,Fruits,Nov-2003,310,1,0,white

Texas,Austin,Veggies,Feb-2004,20,0,1,red

Texas,Austin,Veggies,Jun-2004,80,0,0,red

California,LA,Veggies,Jun-2004,80,1,0,brown

Gmail accounts

2005-02-02T18:14:00.000-08:00

Every one seems to be talking about gmail these days. I feel left out for not having one.

If any one wants to send me an invite, please send it to
ofey_aikon at yahoo dot com

:)

Wow! Thank you for all the invites that you guys have sent me. I'm gonna play with gmail now.

I found a few more ppm repositories

2005-01-24T18:43:00.000-08:00

I found a few more ppm repositories from this perlmonks thread.

http://ppd.develop-help.com/ppd/
http://www.roth.net/perl/packages/
http://www.xray.mpe.mpg.de/~ach/ptk/ppm/
http://theoryx5.uwinnipeg.ca/ppmpackages/
http://dada.perl.it/PPM
http://jenda.krynicky.cz/perl
http://rto.dk/packages/
http://openinteract.sourceforge.net/ppmpackages/
http://ppm.gingerall.cz
http://www.epn.ml.org/~spurkis/Agent/repository
http://homepage.eircom.net/~jmcnamara/perl

DateTime.ppd for Activeperl

2005-01-22T22:23:00.000-08:00

The folks at Activestate seem to be having trouble compiling the DateTime.pm module.

Luckily I found a DateTime.ppd here

Gtk2::Ex::RecordsFilter

2005-01-21T15:52:00.000-08:00

Gtk2::Ex::RecordsFilter - A high level widget to browse reasonably large amounts of relational data and select a subset of records. This widget is inspired by the song browser of iTunes.

DESCRIPTION
When working with large amounts of relational records (csv files, database records, music files index), a common task is to filter out a subset or records from a given set. For example, in a master-detail database design, the master recordset, which is typically smaller than the detail recordset, can be filtered out and the filtered subset of master records can then be used to perform additional tasks on the detail records that they point to.

A common example of this usage is your own mp3 player application (for example, the iTunes application). This application will allow you to choose an mp3 file (the detail record) based on criteria such as Artist, Album, Song (the master record). Once the master record is choosen (i.e., the Artist, Album and Song) it then performs a task on the detail record (i.e., play the mp3 file).

USER INTERACTION

The top half the widget shows all the master records. The records are shown in a hierarchical fashion similar to the iTunes song browser. Clicking on a parent node on the left-most box will cause all the boxes on its right to show only the child nodes.

The user can click on multiple records in the top half using the CTRL key.