From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tremer To: development@lists.ipfire.org Subject: Re: [PATCH] Fix for bug 12539 Date: Thu, 10 Dec 2020 16:46:38 +0100 Message-ID: In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="===============5676713021493074942==" List-Id: --===============5676713021493074942== Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi, > On 10 Dec 2020, at 16:26, Bernhard Bitsch wrote: >=20 >=20 >=20 >> Gesendet: Donnerstag, 10. Dezember 2020 um 15:48 Uhr >> Von: "Michael Tremer" >> An: "Bernhard Bitsch" >> Cc: "IPFire: Development-List" >> Betreff: Re: [PATCH] Fix for bug 12539 >>=20 >> Hello, >>=20 >>> On 10 Dec 2020, at 15:35, Bernhard Bitsch wrot= e: >>>=20 >>> Hi, >>>=20 >>>> Gesendet: Donnerstag, 10. Dezember 2020 um 14:29 Uhr >>>> Von: "Michael Tremer" >>>> An: "Bernhard Bitsch" >>>> Cc: "Adolf Belka" , development(a)lists.ipfire.o= rg >>>> Betreff: Re: [PATCH] Fix for bug 12539 >>>>=20 >>>> Hi, >>>>=20 >>>>> On 10 Dec 2020, at 14:13, Bernhard Bitsch wr= ote: >>>>>=20 >>>>> Hello, >>>>>=20 >>>>>> Gesendet: Donnerstag, 10. Dezember 2020 um 13:48 Uhr >>>>>> Von: "Michael Tremer" >>>>>> An: "Adolf Belka" >>>>>> Cc: development(a)lists.ipfire.org >>>>>> Betreff: Re: [PATCH] Fix for bug 12539 >>>>>>=20 >>>>>> Hello, >>>>>>=20 >>>>>> Great work. This looks like how it should be. >>>>>>=20 >>>>>>> On 7 Dec 2020, at 15:01, Adolf Belka wrote: >>>>>>>=20 >>>>>>> The installer recognises cups and cups-filters both as cups and puts >>>>>>> two instances of cups in the add-on services table. >>>>>>> Based on input from Michael Tremer this patch replaces the command >>>>>>> returning the second element between hyphens with one that takes >>>>>>> what comes after "meta-" using Perl code rather than a shell command. >>>>>>> The second find command was changed as per Michael's suggestion. >>>>>>>=20 >>>>>>> Tested in my ipfire test bed system and only results in one cups >>>>>>> entry. >>>>>>> Signed-off-by: Adolf Belka >>>>>>> --- >>>>>>> html/cgi-bin/services.cgi | 9 +++++---- >>>>>>> 1 file changed, 5 insertions(+), 4 deletions(-) >>>>>>>=20 >>>>>>> diff --git a/html/cgi-bin/services.cgi b/html/cgi-bin/services.cgi >>>>>>> index 26ab4f314..36954ba70 100644 >>>>>>> --- a/html/cgi-bin/services.cgi >>>>>>> +++ b/html/cgi-bin/services.cgi >>>>>>> @@ -161,19 +161,20 @@ END >>>>>>> my $lines=3D0; # Used to count the outputlines to make different bgc= olor >>>>>>>=20 >>>>>>> # Generate list of installed addon pak's >>>>>>> - my @pak =3D `find /opt/pakfire/db/installed/meta-* 2>/dev/null | cu= t -d"-" -f2`; >>>>>>> + opendir (DIR, "/opt/pakfire/db/installed") || die "Cannot opendir /= opt/pakfire/db/installed/: $!"; >>>>>>> + my @pak =3D sort readdir DIR; >>>>>>> foreach (@pak){ >>>>>>> chomp($_); >>>>>>> + next unless (m/^meta-/); >>>>>>> + s/^meta-//; >>>>>>=20 >>>>>> Although this is the least intuitive thing to do. I have no idea who d= esigned Perl. I hope they are proud of all the chaos they have created :) >>>>>>=20 >>>>>> -Michael >>>>>=20 >>>>> Can't see where the solution is 'least intuitive'. As far as I can see = from the patch, now the directory of installed addons is read with Perl funct= ions ( not in a extra forked process ). The definition of filenames is used c= onsequently ( 'meta-', possible services are stored in /etc/init.= d/ ). >>>>=20 >>>> To be clear, I am complaining about the Perl language design instead of = the code. In my view something like >>>>=20 >>>> name =3D name.replace(=E2=80=9Cmeta-=E2=80=9C, =E2=80=9C=E2=80=9D) >>>>=20 >>>> is a thousand times easier to read. >>>>=20 >>>> Best, >>>> -Michael >>>>=20 >>>=20 >>> Okay, that makes it clearer.=20 >>> Perl has its roots in pattern matching. So the base functions of matching= and replacing are defined with minimal overhead in writing. >>> Maybe the designer(s) of Perl had in mind the description of COBOL as "sp= eaking english with your computer". This was in the beginnings of computing, = which did not experience all of us. ;) >>> With this single example you are right. Your formulation is much more rea= dable ( besides the fact that name is a string object ). But if you have many= such snippets in your code, the Perl way makes a shorter and thus more under= standable program. >>=20 >> I disagree. Why would the usage of something that is hard to comprehend be= better when it is being used more often? Getting used to the wrong pattern d= oesn=E2=80=99t make it right. >>=20 >> My main complaint about this is, that it is not clear what is being manipu= lated. It is better to use the variable name and then there is no confusion a= bout it. The same is true for loads of other Perl-isms like shift, chomp, cho= p, etc. >>=20 >> Shorter code does not necessarily mean that it executes faster. Probably t= he opposite is true in this case, because you would have to compile a regular= expression first and the Python version would simply perform a string search. >>=20 >> The point is, that code should be obvious. It avoids bugs and it makes it = easier to understand for reviewers what is supposed to go on. >>=20 >=20 > The main difference between the Perl and the Python approach is the basic l= anguage class. Python works on objects and with their methods ( functions ), = Perl works on plain variables with operators. Types are determined by the ope= rator and context. Each operator has also a result which isn't destroyed by a= assigment or statement end. This result is hold in a special variable which = can be manipulated directly.=20 > If I review code, I should know this basics. Thus it doesn't make a real di= fference in comprehension ( to me ) if I read a object-oriented Python code o= r a Perl code. Nevertheless is the Perl code shorter. In our special example = Perl avoids the generation (in written code ) of an intermeditiate variable b= y use of the implicit $_. > But this is a case of habit. Some like to talk in English only, some like t= o talk in their native language to be more exact. ;) Yes, I understand that. But what do you do when you have more than one variab= le? Most of my code does. > Best, > Bernhard >> Best, >> -Michael >>=20 >>>=20 >>> Best, >>> Bernhard >>>=20 >>>>>=20 >>>>> - Bernhard >>>>>=20 >>>>>=20 >>>>>>=20 >>>>>>>=20 >>>>>>> # Check which of the paks are services >>>>>>> - my @svc =3D `find /etc/init.d/$_ 2>/dev/null | cut -d"/" -f4`; >>>>>>> - foreach (@svc){ >>>>>>> + if (-e "/etc/init.d/$_") { >>>>>>> # blacklist some packages >>>>>>> # >>>>>>> # alsa has trouble with the volume saving and was not really stopp= ed >>>>>>> # mdadm should not stopped with webif because this could crash the= system >>>>>>> # >>>>>>> - chomp($_); >>>>>>> if ( $_ eq 'squid' ) { >>>>>>> next; >>>>>>> } >>>>>>> -- >>>>>>> 2.29.2 --===============5676713021493074942==--