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The Awk Programming Language

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Re: The Awk Programming Language

#41

Post by pdw »

siraben wrote: post #19
bluetomcat wrote: post #16

Earlier quoted context omitted.

Is there a particular benefit in writing a VM in AWK, placed in a big BEGIN block? Very similar code can be written in Perl or Python. Isn't the strength of AWK in its line-matching capability, being able to pattern-match a line against a block of code?

> Is there a particular benefit in writing a VM in AWK Not really. Later on the book just ran out of line-matching examples to go through and started doing regular programming instead :P. When I actually write AWK code I rely on line-matching and using a variable to handle state.

At the time, awk was the only scripting language (other than shell) generally available on Unix systems. Perl, Tcl, Python didn't exist yet. So awk was often used for general-purpose programming.

Re: The Awk Programming Language

#42

Post by tyingq »

joeythedolphin wrote: post #28
kqr wrote: post #21

Earlier quoted context omitted.

This is exactly why I moved from AWK to Perl for these quick jobs a couple of years ago. If you stick to an AWK-like subset, Perl is also simple, fast and lightweight. If you want to grow your scripts (and you have a lot of discipline) Perl – in contrast to AWK – gives you enough noose to hang^W^W^W^Wthe tools you need.

Perl? Wow. Is that better than bash, python or even nodejs? Why write in Perl over these? Serious question, was propaghandized to hate Perl.

The same shortcut syntax that people complain about does make perl really handy for one-time tasks where you're iterating on ideas. Lots of features there that make that easy. One example:

  #!/usr/bin/perl
  while () {
      # various processing here
      # $ARGV is set to either "-" for piped input, or the current filename
      # $_ is the data of the current line
  }
That () construct accepts data from stdin, redirection or file(s) named as arguments and iterates over the data. There's lots of things like that throughout the language.

Re: The Awk Programming Language

#43

Post by Rediscover »

snitty wrote: post #40
usrbinbash wrote: post #3

Earlier quoted context omitted.

> but the fact that is simple, fast and lightweight I see awk as a DSL to be honest. Yes, it can be used as a general purpose language, but that quickly becomes, as you say, awkward :D Like many DSLs, it is simple, fast and lightweight as long as it is used for it's intended purpose . Once you start using it for something else, these advantages evaporate pretty quickly, because then you have to essentially work aroun…

DSL == Domain Specific Language?

Yes

Re: The Awk Programming Language

#44

Post by Woeps »

joeythedolphin wrote: post #28
kqr wrote: post #21

Earlier quoted context omitted.

This is exactly why I moved from AWK to Perl for these quick jobs a couple of years ago. If you stick to an AWK-like subset, Perl is also simple, fast and lightweight. If you want to grow your scripts (and you have a lot of discipline) Perl – in contrast to AWK – gives you enough noose to hang^W^W^W^Wthe tools you need.

Perl? Wow. Is that better than bash, python or even nodejs? Why write in Perl over these? Serious question, was propaghandized to hate Perl.

Perl better? maybe or maybe not.

It can be very useful and they are pretty robust. I often found Perl scripts running for years and years without issues at different companies.

My main issue with Perl-scripts is that they often are not "readable" by anybody but the original creator. Which of course left the company. (not a fault of Perl itself tough)

But your millage may vary and any script can be made (un)readable.

Re: The Awk Programming Language

#46

Post by ufo »

bluetomcat wrote: post #16
siraben wrote: post #10

Awk is awesome! Glad that they are looking to modernize the book. It wasn't really necessary, all the code examples in the original edition of the book still run just fine, although some are somewhat dated, like printing ASCII bar graphs. They also had examples of writing VMs, parsers and interpreters in the book, which run on modern implementations.[0] The language has some quirks. To declare temporary variables, it…

Is there a particular benefit in writing a VM in AWK, placed in a big BEGIN block? Very similar code can be written in Perl or Python. Isn't the strength of AWK in its line-matching capability, being able to pattern-match a line against a block of code?

I love telling about that example to my programming language friends.

> Hey you should read the AWK book, it even says how to write a VM!

> Why would I ever want to use AWK for that?

> Well, the input is a text file with one space-delimited instruction per line.

> Hmm... You have a point.

Re: The Awk Programming Language

#47

Post by technofiend »

Seems like the best time to ask since this is an awk thread: if anyone has a line on the original artwork or a source for the awk t-shirt please let me know. From memory it's of a gangly bird jumping / parachuting from an airplane (DC3?) and captioned with awk's infamous catch-all error message: "Awk: bailing out near line one".

Re: The Awk Programming Language

#49

Post by Simon_O_Rourke »

benhoyt wrote: post #25

I was privileged to be one of the technical reviewers for this book. There's a fair bit of the original content (which is still great), but Kernighan's done a great job with some good restructuring and some significant updates, too. The early chapters are very hands-on, with something of a focus on "exploratory data processing", particularly with CSV files. Big data with AWK, you could say. Gawk and awk will soon hav…

> Gawk and awk will soon have a new "--csv" option that enables proper CSV input mode

Awesome!!!! Super excited to see this!

Re: The Awk Programming Language

#50

Post by calvinmorrison »

benhoyt wrote: post #25

I was privileged to be one of the technical reviewers for this book. There's a fair bit of the original content (which is still great), but Kernighan's done a great job with some good restructuring and some significant updates, too. The early chapters are very hands-on, with something of a focus on "exploratory data processing", particularly with CSV files. Big data with AWK, you could say. Gawk and awk will soon hav…

Its a crying shame we never settled on a control character separated text format. There's a ascii control characters for record and field (unit) separators. A bit of user space support for that would have been great.
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