From mark at purdue.edu  Sun Sep  1 17:19:42 2019
From: mark at purdue.edu (Mark Senn)
Date: Sun, 01 Sep 2019 20:19:42 -0400
Subject: [Purdue-pm] Perl Weekly Challenge
Message-ID: <40737.1567383582@pier.ecn.purdue.edu>

This week's Perl Weekly Challenge problem was at
https://perlweeklychallenge.org/blog/perl-weekly-challenge-023/
It includes recaps of some previous problems by several people.



My blog for this week's forward difference task is at
    https://engineering.purdue.edu/~mark/pwc-023-1.pdf
The Perl 6 code:
    #
    # Perl Weekly Challenge - 023
    # Task #1
    #
    # See
    #     engineering.purdue.edu/~mark/blog/pwc-023-1.pdf
    # for more information.
    #

    # Run using Perl v6.d.
    use v6.d;

    # Get command line arguments.
    my $order = shift @*ARGS;
    my @x = @*ARGS;

    my $i = 1;
    while  @x.elems > 1 && $i <= $order  {
        # <<->> is a hyperoperator
        # if @x = (10,20,30,40), then
        @x = @x[1..*] <<->> @x[0..^*-1];
        # gives (20-10,30-20,40-30) = (10,20,30)

        say "order {$i++}: {@x}";
    }



My blog for this week's factoring numbers task is at
    https://engineering.purdue.edu/~mark/pwc-023-2.pdf
The Perl 6 code:
    #
    # Perl Weekly Challenge - 023
    # Task #2
    #
    # See
    #     engineering.purdue.edu/~mark/blog/pwc-023-2.pdf
    # for more information.
    #

    # Run using Perl v6.d.
    use v6.d;

    my $n = 228;    # number to factor

    # for 2, 3, 5, 7, ..., if the number is prime enter the loop
    for  (2, 3, *+2 ... *).grep({.is-prime}) -> $p  {

        while  $n %% $p  {    # $n evenly divisible by the current prime?
            say $p;           #     print the prime
            $n div= $p;       #     divide $n by the prime
        }

        # Is $p > $n.sqrt?
        # But, I suspect $p ** 2 > $n (= $p * $p > $n) , is faster to compute.
        if ($p ** 2 > $n)  {
            $n.say;
            last;
        }

    }



-mark

From mark at purdue.edu  Thu Sep  5 10:09:22 2019
From: mark at purdue.edu (Mark Senn)
Date: Thu, 05 Sep 2019 13:09:22 -0400
Subject: [Purdue-pm] programming fonts
Message-ID: <10032.1567703362@pier.ecn.purdue.edu>

Over the past ten years or so, I've evaluated probably around
20 fonts for programming and have used the following (one at a
time for months or years).

Inconsolata dz

Inconsolata g (liked dot in zero better)

Adobe Source Code Pro (the ell looks like this only curvier
-|
 |
 |_
It is hard to mistake it for a one.

IBM Plex Mono Regular.   I like ( { [ and ] } ) better thn Source Code
Pro's version of those glpyhs (an "A" can be represted by a hex number
41 in a computer, a glyph is the pictorial representation or symbol
for that character).  I don't like the ell in Source Code Pro.
It isn't ellish enough to suit me.
Ell, 1, and the pipe symbol (|) all  look different.
Parens, braces, and brackets all look different.
Has dotted zero that I like better than slashed zero.
Dotted zero and capital oh look different and dotted zero
looks different from an eight.
It's contemporary.
Comes in lots of styles and weights.
The LaTeX plex package supports it.
Plex has all the Unicode characters I'v tried using from Emacs.
It's open-source.

Mark Senn, Senior Software Engineer,
Engineering Computer Network, Purdue University

From mark at purdue.edu  Sun Sep  8 10:43:33 2019
From: mark at purdue.edu (Mark Senn)
Date: Sun, 08 Sep 2019 13:43:33 -0400
Subject: [Purdue-pm] what proramming fonts do you recommend?
Message-ID: <14852.1567964613@pier.ecn.purdue.edu>

I'm writing a blog entry about fonts.  I'll show pictures of the font
along with pictures of other fonts to compare and contrast, etc.  I'm
only interested in information about free fonts.

Do you know of any fonts that are especially good for programming, or
especially bad fonts to contrast with the better fonts?

Following my signature (i.e., "-mark") is the message I sent to Purdue
Perl Mongers earlier about fonts.

-mark

To: Purdue Perl Mongers <purdue-pm at pm.org>
From: Mark Senn <mark at purdue.edu>
Subject: programming fonts
Date: Thu, 05 Sep 2019 13:09:22 -0400

Over the past ten years or so, I've evaluated probably around
20 fonts for programming and have used the following (one at a
time for months or years).

Inconsolata dz

Inconsolata g (liked dot in zero better)

Adobe Source Code Pro (the ell looks like this only curvier
-|
 |
 |_
It is hard to mistake it for a one.

IBM Plex Mono Regular.   I like ( { [ and ] } ) better thn Source Code
Pro's version of those glpyhs (an "A" can be represted by a hex number
41 in a computer, a glyph is the pictorial representation or symbol
for that character).  I don't like the ell in Source Code Pro.
It isn't ellish enough to suit me.
Ell, 1, and the pipe symbol (|) all  look different.
Parens, braces, and brackets all look different.
Has dotted zero that I like better than slashed zero.
Dotted zero and capital oh look different and dotted zero
looks different from an eight.
It's contemporary.
Comes in lots of styles and weights.
The LaTeX plex package supports it.
Plex has all the Unicode characters I'v tried using from Emacs.
It's open-source.

Mark Senn, Senior Software Engineer,
Engineering Computer Network, Purdue University



-mark

From mark at purdue.edu  Wed Sep 18 08:17:14 2019
From: mark at purdue.edu (Mark Senn)
Date: Wed, 18 Sep 2019 11:17:14 -0400
Subject: [Purdue-pm] Emacs editor crash course
Message-ID: <27487.1568819834@pier.ecn.purdue.edu>

The Purdue Linux Users Group is giving a "Emacs crash course" on
Thursday, September 19th from 6--7pm in REC 226.  The talk will be about
the basics of using the Emacs text editor [1].  The REC (Recitation)
building is on Oval Drive surrounding the Memorial Mall---see campus
map [2]---it is not far from the intersection of State and Marsteller.

(I used the vi editor until the late 1970s then switched to Emacs and
have never looked back.  I use Emacs on Linux for all editing (except
Mathematica [3] notebooks) and reading/sending/etc. of plain text email
messages.  Emacs also runs on Windows, MacOS, and other operating
systems.  It is very programmable.)

[1]  https://www.gnu.org/software/emacs/
[2]  https://www.purdue.edu/campus_map/
[3]  https://www.wolfram.com/mathematica/

-mark

From mark at purdue.edu  Sun Sep 22 17:19:34 2019
From: mark at purdue.edu (Mark Senn)
Date: Sun, 22 Sep 2019 20:19:34 -0400
Subject: [Purdue-pm] Perl Weekly Challenge - 026
Message-ID: <16403.1569197974@pier.ecn.purdue.edu>

My blog entries with my solutions are in


https://engineering.purdue.edu/~mark/pwc-026-1.pdf

Four different ways to count the number of letters
in one string that occur in another.  The different
solutions are
    o  array-based
    o  cross-product based
    o  hash-based
    o  set-based


https://engineering.purdue.edu/~mark/pwc-026-2.pdf

Computing mean angles of a given list of angles in
degrees.  Perl 6 apparently does math using numerical
approximations instead of symbolically like Mathematica.
I suspect Mathematica would compute exactly the right
answers.  It would be nice if the Perl developers would
update Perl to have the technology that Mathematica has
had for over 30 years.  (That would be a lot of work
to do correctly for the general case.)


-mark

From jacoby.david at gmail.com  Thu Sep 26 10:10:06 2019
From: jacoby.david at gmail.com (Dave Jacoby)
Date: Thu, 26 Sep 2019 13:10:06 -0400
Subject: [Purdue-pm] function parameter order question
Message-ID: <CAGbe8xrxkpHFGUEHO4Yn3jrhPWVVTJuiwTfgV-K9r9_1-qLRJg@mail.gmail.com>

If you have a function that's going to read a file and return the output,
and perhaps trigger special behavior if no permissions or file doesn't
exist or something, how would you handle parameters?

What I am engaging right now looks like this.

    read_this_file( $special , $output, $input );

Where $output is an arrayref.

What I think is a better way of doing this is

    $output = read_this_file( $input , $special );

With the signatures feature in more recent Perls, you can set the signature
like

    sub read_this_file ( $input , $special = 1 ) { ... }

so that it defaults to the wanted behavior, or reverse it or not. Of
course, with old syntax, you could also do it.

sub read_this_file {
    my $file = shift;
    my $special = shift;
    $special //= 1;
    ...
}

So it's more the question of param syntax than function header syntax.

Do any of you have strong behavior?

-- 
Dave Jacoby
jacoby.david at gmail.com

I deal with my software the way I treat my eldritch abomination:
 It's not human, it's not even alive in the natural sense.
 It's nightmare-born and nightmare-shaped, and nightmares don't die easy.
  -- @yenzie
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From mark at purdue.edu  Thu Sep 26 11:30:05 2019
From: mark at purdue.edu (Mark Senn)
Date: Thu, 26 Sep 2019 14:30:05 -0400
Subject: [Purdue-pm] function parameter order question
In-Reply-To: <CAGbe8xrxkpHFGUEHO4Yn3jrhPWVVTJuiwTfgV-K9r9_1-qLRJg@mail.gmail.com>
References: <CAGbe8xrxkpHFGUEHO4Yn3jrhPWVVTJuiwTfgV-K9r9_1-qLRJg@mail.gmail.com>
Message-ID: <24648.1569522605@pier.ecn.purdue.edu>

Dave Jacoby wrote:
|  If you have a function that's going to read a file and return the output,
|  and perhaps trigger special behavior if no permissions or file doesn't
|  exist or something, how would you handle parameters?
|
|  What I am engaging right now looks like this.
|
|      read_this_file( $special , $output, $input );
|
|  Where $output is an arrayref.
|
|  What I think is a better way of doing this is
|
|      $output = read_this_file( $input , $special );
|
|  With the signatures feature in more recent Perls, you can set the signature
|  like
|
|      sub read_this_file ( $input , $special = 1 ) { ... }
|
|  so that it defaults to the wanted behavior, or reverse it or not. Of
|  course, with old syntax, you could also do it.
|
|  sub read_this_file {
|      my $file = shift;
|      my $special = shift;
|      $special //= 1;
|      ...
|  }
|
|  So it's more the question of param syntax than function header syntax.
|
|  Do any of you have strong behavior?

OF THE CHOICES ABOVE

Of the choices above I would do
    $output = read_this_file($input, $special);

If I WERE WRITING THE CODE FROM SCRATCH

Because I list arguments in temporal order I would list $input
before $output if both were arguments.

When programming I like to handle error conditions right away
so I don't have to worry about them later in the program.

If I were writing code from scratch to do this I'd probably do
    if ($special = ReadFile($fn, $output))  {
        # (I always use $fn as an abbreviation for "file name".)
        # Handle whatever special is complaining about
        # so I don't have to think about it anymore.
    }
    # rest of code goes here

I don't like using "_" in names.  Perl 6 allows "-", just like COBOL, I
think that's much better than "_".  I usually use camel case, in Perl 5
for my sub names.  In this example the "R" and "F" are the camel's humps
because they're higher than the surrounding characters.
If forced to use $special as an argument I would put it last.
    $output = ReadFile($fn, $special)

(In Wolfram Language where all the system functions are in camel case
I use all lowercase for my functions.)

-mark

From mark at purdue.edu  Sun Sep 29 19:27:54 2019
From: mark at purdue.edu (Mark Senn)
Date: Sun, 29 Sep 2019 22:27:54 -0400
Subject: [Purdue-pm] KLAF data in Mathematica
Message-ID: <15304.1569810474@pier.ecn.purdue.edu>

Thought people might be interested in how to get KLAF airport data, and
Lafayette city data for temperatures in Mathematica.

To load the available data for KLAF from 1800 through 2018 just type
    data = AirTemperatureData["KLAF", {{1800, 1, 1}, {2018, 12, 31}, "Day"}];
That makes Mathematica contact Wolfram Research's server to get their
curated data.  Wolfram Research has a very wide and deep collection of
data.  Purdue has a site license for Mathematica.  Wolfram Research
calls Mathematica "The world's definitive system for modern technical
computing".  I couldn't agree more.  I use Perl 6 for systems
programming and general programming and Mathematica for math, calculus,
physics, engineering, etc. stuff that Perl 6 can't do conveniently or
precisely.
    
The Mathematica notebook source for an example of getting data for
the airport, for Lafayette, and plotting the data is at
    engineering.purdue.edu/~mark/klaf.nb

A PDF file of the Mathematica notebook is at
    engineering.purdue.edu/~mark/klaf.pdf

-mark