If you use a specific language to implement a design pattern what you have is a
'module' or a 'class'. One uses a language to IMPLEMENT a design pattern. The pattern exists without the language.
I sort of agree. The design patterns shown in the Gang of Four (GOF) book are about class hierarchies, not their implementation in any particular language. However, they have provided implementations of these patterns in Smalltalk and C++. Later books have converted these implementations to Java, COBOL, and several other languages. It's fair enough that Perl programmers get a look in!
Again, although the patterns in GOF are fairly non-specific as to target language, later publications have emphasized language-dependent patterns. I'm sure that many of these patterns may prove to be directly transferable to mod_perl, but some will not. Likewise, I'm sure that some patterns will be found that are suitable for Perl but which are not transferable to Java.
Damian mentioned design patterns as one of the skills necessary to become a better programmer. As very little has been written about implementing design patterns in Perl, I've started a project to produce Perl implementations (and explanations) of the Gang of Four's patterns. Later, I hope that Perl-specific patterns may emerge, but for the moment I'm just trying to create interest in this important area for OO-Perl programmers.
The cache is shared amongst all threads and it is only updated when a write operation is made to the database for a new posting, en edit, or a deletion. Such a cache would be very difficult to implement in something like PHP or PERL because it's not possible to share persistent objects among different instances of an interpreted script.
I don't know about PHP, so I won't make any comment about that language, but Perl has an adequate interface for sharing persistent objects in the form of the CPAN module IPC::Shareable:
IPC::Shareable allows you to tie a variable to shared memory making it easy to share the contents of that variable with other Perl processes. Scalars, arrays, and hashes can be tied. The variable being tied may contain arbitrarily complex data structures - including references to arrays, hashes of hashes, etc.
IPC::Shareable implements tie()ing objects to shared memory too. Since an object is just a reference, the same principles (and caveats) apply to tie()ing objects as other reference types.
Codifying a set of "best practicies" that, when applied, assure a solid product.
I think it's unlikely that a set of 'best practices' could encompass some of the contradictory approaches to systems analysis and design, without resorting to lowest-common-denominator definitions such as 'planning is good, design is good, testing is good'.
For example, I am probably not alone among UK coders to have been taught that SSADM was a good method for analysing a large software project. XP basically refutes the idea that structured methodologies are good for any project that has rapidly changing requirements.
I went to a meeting last night held by some guys from consume the net, a London-based community wireless project. The question-and-answer session brought up some questions that didn't seem to have been solved:
If I share my Internet bandwidth with the rest of my street, what's the incentive for my next-door neighbour to increase the communal bandwidth?
Same question, but from a different angle. Since the ISPs' business plans rely on underuse of bandwidth, isn't it obvious that a sucessful bandwidth-sharing project will lead to either withdrawal of service, or increased charges?
Everyone will be looking to get maximum coverage out of their antennas, and the current cards tend to lock onto the strongest signal. If I set up an antenna on my chimney, am I going to deny service to the graphic designer trying to use his AirPort card next door?
Overall, the guys running the project were helpful, and obviously trying to move forward by consensus. I think I'll buy the kit and get involved. However, there remain many problems with such schemes, both technical and legal, and it's only worthwhile getting involved at this early stage for the 'how does it work' factor.
German and English lyrics. I have no idea what is so controversial:
Hast Du etwas Zeit fuer mich
Dann singe ich ein Lied fuer Dich
Von 99 Luftballons
Auf ihrem Weg zum Horizont
Denkst Du vielleicht grad' an mich
Dann singe ich ein Lied fuer Dich
Von 99 Luftballons
Und dass sowas von sowas kommt
You and I in a little toy shop
Buy a bag of balloons with the money we've got.
Set them free at the break of dawn
'Til one by one, they were gone.
Back at base, bugs in the software
Flash the message, Something's out there.
Floating in the summer sky.
99 red balloons go by.
99 Luftballons
Auf ihrem Weg zum Horizont
Hielt man fuer UFOs aus dem All
Darum schickte ein General
Eine Fliegerstaffel hinterher
Alarm zu geben, wenn es so war
Dabei war da am Horizont
Nur 99 Luftballons
99 red balloons.
floating in the summer sky.
Panic bells, it's red alert.
There's something here from somewhere else.
The war machine springs to life.
Opens up one eager eye.
Focusing it on the sky.
Where 99 red balloons go by.
99 Duesenjaeger
Jeder war ein grosser Krieger
Hielten sich fuer Captain Kirk
Das gab ein grosses Feuerwerk
Die Nachbarn haben nichts gerafft
Und fuehlten sich gleich angemacht
Dabei schoss man am Horizont
Auf 99 Luftballons
99 Decision Street.
99 ministers meet.
To worry, worry, super-scurry.
Call the troops out in a hurry.
This is what we've waited for.
This is it boys, this is war.
The president is on the line
As 99 red balloons go by.
99 Kriegsminister
Streichholz und Benzinkanister
Hielten sich fuer schlaue Leute
Witterten schon fette Beute
Riefen: Krieg und wollten Macht
Mann, wer haette das gedacht
Dass es einmal soweit kommt
Wegen 99 Luftballons
99 Knights of the air
Ride super-high-tech jet fighters
Everyone's a superhero.
Everyone's a Captain Kirk.
With orders to identify.
To clarify and classify.
Scramble in the summer sky.
As 99 red balloons go by.
99 Jahre Krieg
Liessen keinen Platz fuer Sieger
Kriegsminister gibt es nicht mehr
Und auch keine Duesenflieger
Heute zieh ich meine Runden
Seh die Welt in Truemmern liegen
Hab' nen Luftballon gefunden
Denk' an Dich und lass' ihn fliegen
99 dreams I have had.
In every one a red balloon.
It's all over and I'm standing pretty.
In this dust that was a city.
If I could find a souvenier.
Just to prove the world was here.
And here is a red balloon
I think of you and let it go.
From http://www.ftmarketwatch.com/news/story.asp?guid={ 9883D663-8C39-41B3-8316-D49BBECD9F2E}
World markets plummet after "apparent terrorist attack"
By Heather Peacocke, FTMarketWatch.com 4:29:00 PM BST Sep 11, 2001
LONDON (FTMW) - Global markets slumped on Tuesday afternoon after two aircraft crashed into New York's World Trade Center, causing the collapse of both towers in what President Bush called an "apparent terrorist attack".
Indices plunged in extremely volatile trade as the disaster escalated with reports of planes crashing into the Pentagon in Washington, causing part of the building to collapse. The White House and key federal buildings were evacuated. See Terrorism strikes hit U.S.
The Federal Aviation Authority said all aircraft had been grounded and all flights to the U.S. had been diverted to Canada.
World indices slump
Frankfurt's DAX 30 fell as much as 9 percent before rebounding slightly. It is presently off 7.4 percent at 4,324.4. In Paris, the CAC 40 [FR:1804546] fell 5.6 percent to 4,137.7 while Neuer Markt [DE:1809455] fell 9.3 percent to 827.5.
London's FTSE 100 [UK:1805550] shed 4 percent to 4,830.7 while the FTSE TechMARK [UK:1859502] fell 4.1 percent to 1,285.5. See London market report
Meanwhile, Stockholm's benchmark OEX index fell 8.3 percent, the Amsterdam AEX index [NL:1810101] fell 5.6 percent and Milan's MIB 30 was down 7.5 percent.
Latin American bourses also slumped after the attack. Trading was later halted in Argentina, Chile and Brazil.
The New York Stock Exchange delayed the market open indefinitely and the London Stock Exchange is being evacuated, although trading continued.
Currency markets also saw sharp swings in the wake of the disaster. Sterling hit six-month highs against the dollar at £1.4692 and traded recently at £1.463. The dollar spiked up against the Euro reaching a high around $0.909 and recently traded at $0.9030, up from earlier levels of $0.8975 before the blast.
October Brent Crude soared by $2.42 to $30.01 in London boosting oil majors BP [UK:BP] and Shell [UK:SHEL], up 5 percent and 6.1 percent respectively.
Gold surged, trading at $287, up $16 an ounce in London.
Insurers, airlines hit
European insurers across the board were dumped with UK insurers CGNU [UK:CGNU] and Royal Sun & Alliance [UK:RSA] off more than 9 percent. Germany's Allianz [DE:840400] [US:AZ] dropped 13 percent and Munich Re [DE:843000] plunged 16 percent.
Among the airlines, British Airways [UK:BAY] fell 22 percent and Lufthansa [DE:823212] followed suit, off 10 percent.
US President George W. Bush said on Tuesday that the full resources of the US would be used to "hunt down" the perpetrators of the World Trade Center and Pentagon attacks.
The immediate assumption was that a Middle Eastern group must be responsible for an attack of this magitude and complexity. Palestinian militants made an immediate claim of responsibility. The Democratic Front for the Liberation of Palestinian, a militant splinter group, issued a statement of responsibility to a TV station in Abu Dhabai.
Analysts said the claim should be treated with caution. The DFLP has no history of terrorist attacks outside Israel and the occupied territories. The group was founded in 1969 when it split from the Popular Front for the Liberation of Palestine (PFLP) and opposes the Middle East peace process.
The group conducted numerous small bombings and minor assaults, and some more spectacular operations in Israel during the 1970s, concentrating on Israeli targets. Since 1988 it has been limited to border raids around Israel.
Phil Butterworth-Hayes, the civil aviation editor with the Janes information group, said that aircraft attacks such as those on the WTC were very difficult to stop.
"The whole civil aviation system works on trust. In America,security systems are the responsibility of the Federal Aviation Administration. The first thing the FAA are going to have to do is completely rethink some of the security systems they have in place at the moment," Mr Butterworth-Hayes said.
"Terrorists are always one step ahead of the institutions that really need protection. Once you defeat one aspect of terrorism, you have to battle against something else," he said.
The current problem is that filesystems don't make it easy to store properties of a file. The HFS made a brave attempt by dividing files into content and properties (using data and resource forks), but it still didn't objectify the filesystem. For example, creating children of a particular file necessitated converting the file into a folder and then wondering what the hell you were going to do with the folder properties - were they going to be placed within the folder or within the parent folder.
A solution would be an object-oriented filesystem, that allows every file to have children without nasty conversions, and implements a simple store for properties (a Berkeley DB file would seem a natural solution).
From his user page, it seems he's also given a gushing review of Your Step-by-step Guide to Health and Fitness
by Nina Bal, Mandip Bal.
I'M IN HEAVEN... December 27, 2000
I was nearly 275 pounds of pure unhealthy and unwanted FAT. I started this program about 3 weeks ago and have already lost 18 pounds. I am feeling good and am COMPLETELY confident in your easy to follow guide. I CAN NOT stress it enough!! Thanks you two, you've made it so easy for me to do! For those of you who are hesitant, DON'T BE. It's now or never!!
Although the two books he's reviewed have different publishers, the ISBNs are suspiciously close, and so are likely to have been published by the same parent company.
ISBN: 0968814964 - How to Make Money on the Internet
ISBN: 0968814905 - Your Step-by-step Guide to Health and Fitness
Slashdot Mirror
Compared to around £50 (c.$75) a week in the UK (with higher cost of living in London than in most US cities), this sounds great.
Quit moaning.
She has a common surname. Here's the correct search, which returns 212 results.
blockquoth:
I sort of agree. The design patterns shown in the Gang of Four (GOF) book are about class hierarchies, not their implementation in any particular language. However, they have provided implementations of these patterns in Smalltalk and C++. Later books have converted these implementations to Java, COBOL, and several other languages. It's fair enough that Perl programmers get a look in!
Again, although the patterns in GOF are fairly non-specific as to target language, later publications have emphasized language-dependent patterns. I'm sure that many of these patterns may prove to be directly transferable to mod_perl, but some will not. Likewise, I'm sure that some patterns will be found that are suitable for Perl but which are not transferable to Java.
Damian mentioned design patterns as one of the skills necessary to become a better programmer. As very little has been written about implementing design patterns in Perl, I've started a project to produce Perl implementations (and explanations) of the Gang of Four's patterns. Later, I hope that Perl-specific patterns may emerge, but for the moment I'm just trying to create interest in this important area for OO-Perl programmers.
I don't know about PHP, so I won't make any comment about that language, but Perl has an adequate interface for sharing persistent objects in the form of the CPAN module IPC::Shareable:
I think it's unlikely that a set of 'best practices' could encompass some of the contradictory approaches to systems analysis and design, without resorting to lowest-common-denominator definitions such as 'planning is good, design is good, testing is good'.
For example, I am probably not alone among UK coders to have been taught that SSADM was a good method for analysing a large software project. XP basically refutes the idea that structured methodologies are good for any project that has rapidly changing requirements.
Please give examples of software in use today that have been proven 100% correct. I'd be curious to know how many actually exist.
I think that most coders would agree that 100% correctness is probably impossible, but TeX is about as close as you can get.
I went to a meeting last night held by some guys from consume the net, a London-based community wireless project. The question-and-answer session brought up some questions that didn't seem to have been solved:
Overall, the guys running the project were helpful, and obviously trying to move forward by consensus. I think I'll buy the kit and get involved. However, there remain many problems with such schemes, both technical and legal, and it's only worthwhile getting involved at this early stage for the 'how does it work' factor.
Look at the Server header matching /Microsoft/ returned from a simple HTTP HEAD request. Your input in bold.
$ telnet www.microsoft.com 80Trying 207.46.197.113...
Connected to www.microsoft.akadns.net.
Escape character is '^]'.
HEAD / HTTP/1.0
HTTP/1.1 200 OK
Server: Microsoft-IIS/5.0
P3P: CP='ALL IND DSP COR ADM CONo CUR CUSo IVAo IVDo PSA PSD TAI TELo OUR SAMo CNT COM INT NAV ONL PHY PRE PUR UNI'
Content-Location: http://CPMSFTWBW34/default.htm
Date: Fri, 28 Sep 2001 15:12:58 GMT
Content-Type: text/html
Accept-Ranges: none
Last-Modified: Fri, 28 Sep 2001 12:28:47 GMT
Content-Length: 23232
Connection closed by foreign host.
If you're not eligible to work for Uncle Sam, try here.
add a shorter name to your /etc/hosts
German and English lyrics. I have no idea what is so controversial:
Hast Du etwas Zeit fuer mich
Dann singe ich ein Lied fuer Dich
Von 99 Luftballons
Auf ihrem Weg zum Horizont
Denkst Du vielleicht grad' an mich
Dann singe ich ein Lied fuer Dich
Von 99 Luftballons
Und dass sowas von sowas kommt
You and I in a little toy shop
Buy a bag of balloons with the money we've got.
Set them free at the break of dawn
'Til one by one, they were gone.
Back at base, bugs in the software
Flash the message, Something's out there.
Floating in the summer sky.
99 red balloons go by.
99 Luftballons
Auf ihrem Weg zum Horizont
Hielt man fuer UFOs aus dem All
Darum schickte ein General
Eine Fliegerstaffel hinterher
Alarm zu geben, wenn es so war
Dabei war da am Horizont
Nur 99 Luftballons
99 red balloons.
floating in the summer sky.
Panic bells, it's red alert.
There's something here from somewhere else.
The war machine springs to life.
Opens up one eager eye.
Focusing it on the sky.
Where 99 red balloons go by.
99 Duesenjaeger
Jeder war ein grosser Krieger
Hielten sich fuer Captain Kirk
Das gab ein grosses Feuerwerk
Die Nachbarn haben nichts gerafft
Und fuehlten sich gleich angemacht
Dabei schoss man am Horizont
Auf 99 Luftballons
99 Decision Street.
99 ministers meet.
To worry, worry, super-scurry.
Call the troops out in a hurry.
This is what we've waited for.
This is it boys, this is war.
The president is on the line
As 99 red balloons go by.
99 Kriegsminister
Streichholz und Benzinkanister
Hielten sich fuer schlaue Leute
Witterten schon fette Beute
Riefen: Krieg und wollten Macht
Mann, wer haette das gedacht
Dass es einmal soweit kommt
Wegen 99 Luftballons
99 Knights of the air
Ride super-high-tech jet fighters
Everyone's a superhero.
Everyone's a Captain Kirk.
With orders to identify.
To clarify and classify.
Scramble in the summer sky.
As 99 red balloons go by.
99 Jahre Krieg
Liessen keinen Platz fuer Sieger
Kriegsminister gibt es nicht mehr
Und auch keine Duesenflieger
Heute zieh ich meine Runden
Seh die Welt in Truemmern liegen
Hab' nen Luftballon gefunden
Denk' an Dich und lass' ihn fliegen
99 dreams I have had.
In every one a red balloon.
It's all over and I'm standing pretty.
In this dust that was a city.
If I could find a souvenier.
Just to prove the world was here.
And here is a red balloon
I think of you and let it go.
All UK Government facilities have gone to 'Orange'.
If they're going to say anything, it'll appear here.
From http://www.ftmarketwatch.com/news/story.asp?guid={ 9883D663-8C39-41B3-8316-D49BBECD9F2E}
World markets plummet after "apparent terrorist attack"
By Heather Peacocke, FTMarketWatch.com 4:29:00 PM BST Sep 11, 2001
LONDON (FTMW) - Global markets slumped on Tuesday afternoon after two aircraft crashed into New York's World Trade Center, causing the collapse of both towers in what President Bush called an "apparent terrorist attack".
Indices plunged in extremely volatile trade as the disaster escalated with reports of planes crashing into the Pentagon in Washington, causing part of the building to collapse. The White House and key federal buildings were evacuated. See Terrorism strikes hit U.S.
The Federal Aviation Authority said all aircraft had been grounded and all flights to the U.S. had been diverted to Canada.
World indices slump
Frankfurt's DAX 30 fell as much as 9 percent before rebounding slightly. It is presently off 7.4 percent at 4,324.4. In Paris, the CAC 40 [FR:1804546] fell 5.6 percent to 4,137.7 while Neuer Markt [DE:1809455] fell 9.3 percent to 827.5.
London's FTSE 100 [UK:1805550] shed 4 percent to 4,830.7 while the FTSE TechMARK [UK:1859502] fell 4.1 percent to 1,285.5. See London market report
Meanwhile, Stockholm's benchmark OEX index fell 8.3 percent, the Amsterdam AEX index [NL:1810101] fell 5.6 percent and Milan's MIB 30 was down 7.5 percent.
Latin American bourses also slumped after the attack. Trading was later halted in Argentina, Chile and Brazil.
The New York Stock Exchange delayed the market open indefinitely and the London Stock Exchange is being evacuated, although trading continued.
Currency markets also saw sharp swings in the wake of the disaster. Sterling hit six-month highs against the dollar at £1.4692 and traded recently at £1.463. The dollar spiked up against the Euro reaching a high around $0.909 and recently traded at $0.9030, up from earlier levels of $0.8975 before the blast.
October Brent Crude soared by $2.42 to $30.01 in London boosting oil majors BP [UK:BP] and Shell [UK:SHEL], up 5 percent and 6.1 percent respectively.
Gold surged, trading at $287, up $16 an ounce in London.
Insurers, airlines hit
European insurers across the board were dumped with UK insurers CGNU [UK:CGNU] and Royal Sun & Alliance [UK:RSA] off more than 9 percent. Germany's Allianz [DE:840400] [US:AZ] dropped 13 percent and Munich Re [DE:843000] plunged 16 percent.
Among the airlines, British Airways [UK:BAY] fell 22 percent and Lufthansa [DE:823212] followed suit, off 10 percent.
By FT.com staff - Sep 11 2001 15:35:23
US President George W. Bush said on Tuesday that the full resources of the US would be used to "hunt down" the perpetrators of the World Trade Center and Pentagon attacks.
The immediate assumption was that a Middle Eastern group must be responsible for an attack of this magitude and complexity. Palestinian militants made an immediate claim of responsibility. The Democratic Front for the Liberation of Palestinian, a militant splinter group, issued a statement of responsibility to a TV station in Abu Dhabai.
Analysts said the claim should be treated with caution. The DFLP has no history of terrorist attacks outside Israel and the occupied territories. The group was founded in 1969 when it split from the Popular Front for the Liberation of Palestine (PFLP) and opposes the Middle East peace process.
The group conducted numerous small bombings and minor assaults, and some more spectacular operations in Israel during the 1970s, concentrating on Israeli targets. Since 1988 it has been limited to border raids around Israel.
Phil Butterworth-Hayes, the civil aviation editor with the Janes information group, said that aircraft attacks such as those on the WTC were very difficult to stop.
"The whole civil aviation system works on trust. In America,security systems are the responsibility of the Federal Aviation Administration. The first thing the FAA are going to have to do is completely rethink some of the security systems they have in place at the moment," Mr Butterworth-Hayes said.
"Terrorists are always one step ahead of the institutions that really need protection. Once you defeat one aspect of terrorism, you have to battle against something else," he said.
© Copyright The Financial Times Limited 2001.
news.bbc.co.uk is still responding.
What do you get when you put a baby in a liquidizer?
...
An erection.
Taken with SpeedCam:
Fantastic range of images available here.
Available here. I particularly like the cornstarch balloons.
See also these famous high-speed photos of nuclear tests (and some pictures of the 'shadow effect' from Hiroshima): http://www.fas.org/nuke/hew/Library/Effects/
The current problem is that filesystems don't make it easy to store properties of a file. The HFS made a brave attempt by dividing files into content and properties (using data and resource forks), but it still didn't objectify the filesystem. For example, creating children of a particular file necessitated converting the file into a folder and then wondering what the hell you were going to do with the folder properties - were they going to be placed within the folder or within the parent folder.
A solution would be an object-oriented filesystem, that allows every file to have children without nasty conversions, and implements a simple store for properties (a Berkeley DB file would seem a natural solution).
From his user page, it seems he's also given a gushing review of Your Step-by-step Guide to Health and Fitness by Nina Bal, Mandip Bal.
Although the two books he's reviewed have different publishers, the ISBNs are suspiciously close, and so are likely to have been published by the same parent company.
Astroturfing, I feel.
Yes, the people on dot-slash always read the articles first.