From bradley.d.andersen at gmail.com  Wed Apr  4 10:20:04 2012
From: bradley.d.andersen at gmail.com (Bradley Andersen)
Date: Wed, 4 Apr 2012 13:20:04 -0400
Subject: [Purdue-pm] Why does this work?
Message-ID: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>

  1 #!/usr/bin/env perl
  2
  3 use strict;
  4 use warnings;
  5
  6 use feature 'say';
  7
  8 for my $i(1 .. 10) {;
  9     say $i;
 10 }


?? Why does that work?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/purdue-pm/attachments/20120404/2681d742/attachment.html>

From westerman at purdue.edu  Wed Apr  4 13:28:40 2012
From: westerman at purdue.edu (Rick Westerman)
Date: Wed, 4 Apr 2012 16:28:40 -0400 (EDT)
Subject: [Purdue-pm] Why does this work?
In-Reply-To: <1942813725.84164.1333571284288.JavaMail.root@mailhub016.itcs.purdue.edu>
Message-ID: <1874573518.84166.1333571320642.JavaMail.root@mailhub016.itcs.purdue.edu>

Why shouldn't it work?   I presume you are talking about "why does the null statement after the left brace not interfere with the program?"  If so then the answer is simple -- it is a null statement.

----- Original Message -----
> 1 #!/usr/bin/env perl
> 2
> 3 use strict;
> 4 use warnings;
> 5
> 6 use feature 'say';
> 7
> 8 for my $i(1 .. 10) {;
> 9 say $i;
> 10 }
> 
> 
> ?? Why does that work?
> 
> 
> _______________________________________________
> Purdue-pm mailing list
> Purdue-pm at pm.org
> http://mail.pm.org/mailman/listinfo/purdue-pm

-- 
Rick Westerman 
westerman at purdue.edu

Bioinformatics specialist at the Genomics Facility.
Phone: (765) 494-0505           FAX: (765) 496-7255
Department of Horticulture and Landscape Architecture
625 Agriculture Mall Drive
West Lafayette, IN 47907-2010
Physically located in room S049, WSLR building


From mark at ecn.purdue.edu  Wed Apr  4 13:32:51 2012
From: mark at ecn.purdue.edu (Mark Senn)
Date: Wed, 04 Apr 2012 16:32:51 -0400
Subject: [Purdue-pm] Why does this work?
In-Reply-To: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>
References: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>
Message-ID: <15904.1333571571@pier.ecn.purdue.edu>

    Bradley Andersen wrote:
    > #!/usr/bin/env perl
    > 
    > use strict;
    > use warnings;
    > 
    > use feature 'say';
    > 
    > for my $i(1 .. 10) {;
    >     say $i;
    > }
    > 
    > ?? Why does that work?

>From "http://perldoc.perl.org/perlsyn.html":
    The foreach keyword is actually a synonym for the for keyword,
    so you can use foreach for readability or for for brevity.

The "{;" doesn't cause problems because the statement between
"{" and ";" is zero length and zero length statements are allowed.
This code works fine
    ;;;;;
    say 'hello'
    ;;;;;

-mark

From bradley.d.andersen at gmail.com  Wed Apr  4 13:33:25 2012
From: bradley.d.andersen at gmail.com (Bradley Andersen)
Date: Wed, 4 Apr 2012 16:33:25 -0400
Subject: [Purdue-pm] Why does this work?
In-Reply-To: <15904.1333571571@pier.ecn.purdue.edu>
References: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>
	<15904.1333571571@pier.ecn.purdue.edu>
Message-ID: <CAN+Wnj3WdTxFn3czf5F+Luu2biyR69XL9u9aufjWH6WbyajRvQ@mail.gmail.com>

everyone seems to have missed that i replied already that i turned on my
brain and figured it out :)



On Wed, Apr 4, 2012 at 4:32 PM, Mark Senn <mark at ecn.purdue.edu> wrote:

>    Bradley Andersen wrote:
>    > #!/usr/bin/env perl
>    >
>    > use strict;
>    > use warnings;
>    >
>    > use feature 'say';
>     >
>    > for my $i(1 .. 10) {;
>     >     say $i;
>     > }
>    >
>    > ?? Why does that work?
>
> From "http://perldoc.perl.org/perlsyn.html":
>    The foreach keyword is actually a synonym for the for keyword,
>    so you can use foreach for readability or for for brevity.
>
> The "{;" doesn't cause problems because the statement between
> "{" and ";" is zero length and zero length statements are allowed.
> This code works fine
>    ;;;;;
>    say 'hello'
>    ;;;;;
>
> -mark
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/purdue-pm/attachments/20120404/d3caf4e8/attachment.html>

From jacoby at purdue.edu  Wed Apr  4 13:35:31 2012
From: jacoby at purdue.edu (Dave Jacoby)
Date: Wed, 04 Apr 2012 16:35:31 -0400
Subject: [Purdue-pm] Why does this work?
In-Reply-To: <CAN+Wnj3WdTxFn3czf5F+Luu2biyR69XL9u9aufjWH6WbyajRvQ@mail.gmail.com>
References: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>
	<15904.1333571571@pier.ecn.purdue.edu>
	<CAN+Wnj3WdTxFn3czf5F+Luu2biyR69XL9u9aufjWH6WbyajRvQ@mail.gmail.com>
Message-ID: <4F7CB093.2000907@purdue.edu>

On 4/4/2012 4:33 PM, Bradley Andersen wrote:
> everyone seems to have missed that i replied already that i turned on my
> brain and figured it out :)

That email hasn't come to me.

-- 
Dave Jacoby
     Code Maker, Purdue Genomics Core Lab
     http://web.ics.purdue.edu/~djacoby
         733 days until the end of XP support


From bradley.d.andersen at gmail.com  Wed Apr  4 13:37:43 2012
From: bradley.d.andersen at gmail.com (Bradley Andersen)
Date: Wed, 4 Apr 2012 16:37:43 -0400
Subject: [Purdue-pm] Fwd: Why does this work?
In-Reply-To: <CAN+Wnj1h+DufwxkiVR5ZA=GL+LNbpP6mJ58h97E7KPSM=7F-mA@mail.gmail.com>
References: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>
	<CAN+Wnj1h+DufwxkiVR5ZA=GL+LNbpP6mJ58h97E7KPSM=7F-mA@mail.gmail.com>
Message-ID: <CAN+Wnj0uUsPZ3u9Hj2E8FhSjEx5PRPqJuxJ5z1vcQwZSKaQ0dA@mail.gmail.com>

---------- Forwarded message ----------
From: Bradley Andersen <bradley.d.andersen at gmail.com>
Date: Wed, Apr 4, 2012 at 2:02 PM
Subject: Re: Why does this work?
To: Purdue Perl Mongers <purdue-pm at pm.org>


I just turned on my brain and I think I know why now, sorry :)
(I was referring to line 8)


On Wed, Apr 4, 2012 at 1:20 PM, Bradley Andersen <
bradley.d.andersen at gmail.com> wrote:

>   1 #!/usr/bin/env perl
>   2
>   3 use strict;
>   4 use warnings;
>   5
>   6 use feature 'say';
>   7
>   8 for my $i(1 .. 10) {;
>   9     say $i;
>  10 }
>
>
> ?? Why does that work?
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/purdue-pm/attachments/20120404/970e0ead/attachment.html>

From bradley.d.andersen at gmail.com  Wed Apr  4 11:02:33 2012
From: bradley.d.andersen at gmail.com (Bradley Andersen)
Date: Wed, 4 Apr 2012 14:02:33 -0400
Subject: [Purdue-pm] Why does this work?
In-Reply-To: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>
References: <CAN+Wnj3+=OtHjht9WsAd0yrN7F4pqUPXOZe-EJWC9xjZH6yvNg@mail.gmail.com>
Message-ID: <CAN+Wnj1h+DufwxkiVR5ZA=GL+LNbpP6mJ58h97E7KPSM=7F-mA@mail.gmail.com>

I just turned on my brain and I think I know why now, sorry :)
(I was referring to line 8)

On Wed, Apr 4, 2012 at 1:20 PM, Bradley Andersen <
bradley.d.andersen at gmail.com> wrote:

>   1 #!/usr/bin/env perl
>   2
>   3 use strict;
>   4 use warnings;
>   5
>   6 use feature 'say';
>   7
>   8 for my $i(1 .. 10) {;
>   9     say $i;
>  10 }
>
>
> ?? Why does that work?
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/purdue-pm/attachments/20120404/06daf887/attachment-0001.html>

From mark at purdue.edu  Sat Apr  7 13:31:57 2012
From: mark at purdue.edu (Mark Senn)
Date: Sat, 07 Apr 2012 16:31:57 -0400
Subject: [Purdue-pm] Perl code to use steering wheel on Linux
Message-ID: <12305.1333830717@pier.ecn.purdue.edu>

Purdue Perl Mongers,

I was thinking about giving a talk about this at the next Purdue Perl
Mongers meeting but decided it wasn't a broad enough topic.  Below is
Perl code that reads values from a steering wheel, gas pedal, and brake
pedal attached to a Linux computer.

(T'm building a 18" long radio controlled six wheel drive car that I plan
to drive using a steering wheel on my computer using a web browser.  The
idea is the can could be used anywhere in the world where a web server
would be within radio controlled range of the car.  A makerspace/hackerspace
is in the process of being formed in Lafayette to work on crazy projects
like this.  See
    http://LafayetteMakerspace.org
to sign up for the (two messages a month) mailing list if you're interested.)

-mark

#!/usr/bin/perl
#
#  .index  read information from Genious TwinWheel steering wheel
#
#  .revised  t.pl  2012-04-07  Mark Senn  http://engineering.purdue.edu/~mark
#  .created  t.pl  2012-03-30  Mark Senn  http://engineering.purdue.edu/~mark
#
#  .description
#      .p
#          This program shows how to use Perl to read information from
#          a "Genius TwinWheel F1 Vibration Feedback Racing Wheel for
#          PC ad PS2 games".  This program is based on
#          .verbatim
#              http://search.cpan.org/~bwatson/Linux-Joystick-0.0.1/Joystick.pm#USAGE
#          .everbatim
#      .ep
#      .p
#          The configuration of buttons on the Genius TwinWheel F1 is
#          .verbatim
#                        L2       R2
#                       L1         R1
#        
#                 DV+                   NOR
#              DH-   DH+             WES   EAS
#                 DV-                   SOU
#        
#                        L3       R3
#                         SE    ST
#                           MODE
#          .everbatim
#          where
#          .table
#              BUTTON  DESCRIPTION              BUTTON  DESCRIPTION
#              DV+     D-pad Vertical+          NOR     NORTH
#              DH-     D-pad Horizontal-        WES     WEST
#              DH+     D-pad Horizontal+        EAS     EAST
#              DV-     D-pad Vertical-          SOU     SOUTH
#    
#              SE     SELECT
#              ST     START
#          .etable
#      .ep
#  .edesciption
#
#  .history
#      .he 2012-03-30
#          .p
#              Started.
#          .ep
#      .ehe
#      .he 2012-03-31
#          .p
#              Did more work.
#          .ep
#      .ehe
#      .he 2012-04-07
#          .p
#              Improved code and comments.
#          .ep
#      .ehe
#  .ehistory
#

use strict;
use warnings;

use feature 'say';

use Linux::Joystick;

# Make a steering wheel object.
my $sw = new Linux::Joystick;

say 'The steerig wheel has:';
say '    ', $sw->axisCount(),   ' axes';
say '    ', $sw->buttonCount(), ' buttons';
say 'Pulling right-hand lever towards you is equivalent to pushing the north button.';
say 'Pulling left-hand  lever towards you is equivalent to pushing the east  button.';
say 'Pressing the "MODE" button does not generate an event.';

# Map button numbers to button names.
my %button =
(
     0 => 'NORTH',
     1 => 'EAST',
     2 => 'SOUTH',
     3 => 'WEST',
     4 => 'R2',
     5 => 'L2',
     6 => 'L1',
     7 => 'R1',
     8 => 'SELECT',
     9 => 'START',
    10 => 'L3',
    11 => 'R3',
);


# Printf format.
my $f = "%-6s %-10s %s\n";

# Use blocking reads to wait for the next event.
while (my $e = $sw->nextEvent)
{
    if ($e->isAxis && $e->axis == 0) { printf $f, 'Steer', '',                                $e->axisValue;       next; }
    if ($e->isAxis && $e->axis == 1) { printf $f, 'Speed', '',                                $e->axisValue;       next; }
    if ($e->isAxis && $e->axis == 2) { printf $f, 'D-pad', 'HORIZONTAL',                      $e->axisValue;       next; }
    if ($e->isAxis && $e->axis == 3) { printf $f, 'D-pad', 'VERTICAL',                        $e->axisValue;       next; }
    if ($e->isButton)                { printf $f, 'Button', ($e->buttonDown) ? 'down' : 'up', $button{$e->button}; next; }

    die 'Unknown event ' . $e->hexDump;
}

# If the while loop terminates, we have a false (undefined) event.
die 'Error reading joystick: ' . $sw->errorString;

From jacoby at purdue.edu  Thu Apr 12 12:38:38 2012
From: jacoby at purdue.edu (Dave Jacoby)
Date: Thu, 12 Apr 2012 15:38:38 -0400
Subject: [Purdue-pm] Perl Mongers  Meeting - April 17
Message-ID: <4F872F3E.5040105@purdue.edu>

It's that time again: Time to beat the bushes to make sure we have 
presentations and topics for discussion. Mark has plans to talk about 
driving a robot car with Linux, but I wonder what other things people 
are doing with computing, with Linux and preferably with Perl these 
days. Any other talks out there?

-- 
Dave Jacoby
     Code Maker, Purdue Genomics Core Lab
     http://web.ics.purdue.edu/~djacoby
         725 days until the end of XP support


From mark at purdue.edu  Tue Apr 17 04:44:26 2012
From: mark at purdue.edu (Mark Senn)
Date: Tue, 17 Apr 2012 07:44:26 -0400
Subject: [Purdue-pm] "Data Algebra" talk
Message-ID: <7353.1334663066@pier.ecn.purdue.edu>

Purdue Perl Mongers,
Thought you might be interested in this "Data Algebra" talk.
-mark


Subject: Math Club Special Guest Speaker and Final Talk for the Semester 4/19
From: Nathaniel Johnson <johns576 at purdue.edu>
To: Nathaniel Johnson <johns576 at purdue.edu>

Hey All!

This week we're having another guest speaker coming, Dr. Gary Sherman, the
Principal Mathematician for Algebraix Data Corp. He will be talking to us
about "Data Algebra" how it's developed. Below is his abstract for his
speech.
This will be the last talk for the semester and it promises to be a good
one; so don't miss out!

The talk will be held in a different location this week: MTHW 210 (the
really big room in Matthew's); but still at 6pm on Thursday (April 19th).

TITLE:  What's a data algebra and how do you build one?

ABSTRACT:  Ask n people the question "What's data?" and the
cardinality of the set of responses is better approximated by n than by
one.  Any self respecting mathematician is puzzled by this --- denizens of
data-world, not so much.  Indeed, ever since E. F. Codd's 1970 paper,
A Relational Model of Data for Large Shared Data Banks (Comm. ACM,
Vol. 13, No. 6, pp. 377-387) gave rise to the Relational Data Model (RDM),
the data-world's solution to this congenital ambiguity has been to
exacerbate it by conflating the data, whatever it is, with some prejudicial
visual artifice (tables in the case of the RDM); i.e., by confusing the
message with the paper it's written on --- so to speak.  What is worse,
each new artifice comes equipped with a brief, supposedly-mathematical
incantation to justify the trip down a new rabbit hole.  This talk
discusses Algebraic Data Corporation's approach to knowing data in the
context of Zemelo-Frankel set theory, the foundation for all modern
mathematics and, therefore, the only legitimate incantation to use when
invoking the good name of mathematics.  Indeed, our incantation births a
rigorous notion of data algebra in plain sight of the RDM and its mongrel
spawn, Structured Query Language (SQL).

See You There,

Nate Johnson
Ambassador to the Math Club

From djacoby at purdue.edu  Tue Apr 17 08:34:02 2012
From: djacoby at purdue.edu (David A Jacoby)
Date: Tue, 17 Apr 2012 11:34:02 -0400 (EDT)
Subject: [Purdue-pm] Meeting today
Message-ID: <4EF719D5-9D7F-47D4-AEEB-B329C78E303A@purdue.edu>


Today is the day for Purdue Perl Mongers. The conversation its starting now. WSLR 116.

-- 
Dave Jacoby
  jacoby at purdue.edu
  Not at his desk
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.pm.org/pipermail/purdue-pm/attachments/20120417/e73ecf2c/attachment.html>