13 ms·

The K Language

161 points by vonnik 11y ago

phaefele 11y ago
Has anyone looked at SciDB (http://www.paradigm4.com/ http://www.paradigm4.com/) as a replacement for KDB. Seems like it would fit the bill and has a community edition. I do see some usage in the financial markets.
payne92 11y ago
That looks like more of a grammar. A specification would describe, among many, many, many other things, how big an int is and what happens for overflow, etc.
- baddox 11y ago
  To be fair, those things could all be deliberately unspecified. Granted, the shortness of a language's spec is less impressive when it is simply the result of the language being woefully underspecified.
- dang 11y ago
  Ok, we changed the title from "The Complete Language Spec of K" to something less objectionable.
tlack 11y ago
So is the if syntax shown at the bottom coming to K or is that only for illustration? If not, why not use $[c;t;f] then?
- RodgerTheGreat 11y ago
  A good question. Older versions of K had if and while as syntactic sugar. You could always do without them by using cond and adverbs. K5 did away with these syntactic forms, and for whatever reason Arthur decided to put them back in k6.
wyc 11y ago
Why use such a thing? Array languages are very powerful for dealing with high-dimensional data. R, matlab, octave, and Julia can all do this and are satisfactory for most people. However, proponents claim that languages such as K are much more expressive. The APL family gets a bad rap for being "read-only", but I think it's mostly because they've fallen out of favor and have become unpopular. People who have experience working with these languages can encode/decode incredible amounts of information to/from a few lines once they see "phrases" and "sentences" instead of "my cat chewed the 56k modem line". We don't write Integral() in calculus when we want to take an integral, so why not have similar shorthands in computation? Here's the vocabulary of the sister language J for comparison: http://www.jsoftware.com/help/dictionary/vocabul.htm http://www.jsoftware.com/help/dictionary/vocabul.htm "The one-page thing": http://code.jsoftware.com/wiki/Essays/Incunabulum http://code.jsoftware.com/wiki/Essays/Incunabulum Naive K-Nearest Neighbors implementation: https://github.com/wyc/snippets/blob/master/j/knn.ijs https://github.com/wyc/snippets/blob/master/j/knn.ijs Community: https://www.reddit.com/r/apljk/ https://www.reddit.com/r/apljk/
- minikomi 11y ago
  A nicer to look at J Vocab has been published recently: http://code.jsoftware.com/wiki/NuVoc http://code.jsoftware.com/wiki/NuVoc It's a fun language to use to do /r/dailyprogrammer puzzles.
RodgerTheGreat 11y ago
Specifically, the reference card here is describing "k6".
nickpeterson 11y ago
How would one actually go about getting a username and password, I see these languages often, and know this is the true successor since Whitney is working on it, but i think all of these are neat. Or should I just learn Kona/kerf/xxl?
- olympus 11y ago
  tl;dr: I recommend learning J. If you just want to play around (no commercial use) you can download kdb+ from here: https://kx.com/software-download.php https://kx.com/software-download.php but you only get the 32-bit version for free, so keep your DB under 4 GB. With kdb+ you get K, the language, Q, which is a superset of K, and a column (time-series) oriented database engine. I recommend against using it, because if you want to do something meaningful (like make money somehow) then you need to buy a commercial license. I hear that they cost around $2k per machine (or possibly per core). Kona is nice but it is a full version behind K (Kona is a copy of K3, and kdb+ is on K4) and it isn't quite as fast/optimized. It's great if you are set on using K but don't have the cash and don't need database integration. Kerf (by the same guy who made Kona) has a friendlier syntax but seems to be commercially oriented similar to K (as in email us for free demo software but pay up when you want to do it for real). J is open source, free for commercial use, has some decent tutorials written for it, and even has a free database engine (JDB requires a license for commercial use, but Jd seems to be free for everything. It probably isn't as fast as K, but it has a nice feel to it. The runtime is under 3 MB and even with a Qt IDE and a bunch of extras it's under 30 MB. You can make Qt base GUIs with J and do quite a few things. I started learning J just last week and have been doing some problems on Project Euler to get familiar with it. I like it quite a bit. It even has built in functions for prime factorization, finding the prime number sieve, and and extended precision mode which makes solving some problems very easy.
ktamura 11y ago
While I really like K/Q/J/APL (some of this is Stockholm Syndrome: I spent the first 3 years of my career writing K/Q at a trading firm, eventually becoming the human debugger for my team's K/Q "investment". It got so annoying that I worked on a little parser library to help me debug: https://github.com/kiyoto/ungod https://github.com/kiyoto/ungod), they are doomed from a adoption/future viability point of view. 1. Steep learning curve without benefits: APLs like K/Q/J optimize for concision to the point of unreadability. Sure, it might be fun to decipher clever K/Q one-liners, but if you have to do it everyday for work in production, it's just exhausting. This lack of readability has limited adoption and the growth of its user community. For any technology is to have a viable community, it needs to be usable by a critical mass. K/Q in specific but APLs in general never had that, especially with more user-friendly alternatives like R/Matlab for scientific computing. 2. No open source community. There's Kona (https://github.com/kevinlawler/kona https://github.com/kevinlawler/kona) by Kevin Lawler, but again, its community has been small because the underlying language is not design to be usable by enough people. 3. Domain specificity of array languages: These days, array languages are just too limited in its scope. Scientific computing, the bread and butter of any array programming language, has been made possible in other languages (ex: Python), making array languages not powerful nor compelling enough to use because most of its strengths can be found in other languages and its weaknesses are too crippling. I heard that Arthur Whitney found his successors (a pair of Russian programmers from St. Petersburg, iirc), so K/Q will likely to be around beyond his retirement. That said, I think its user base will continue to shrink for above reasons.
- f3lix133 11y ago
  '3 years of my career writing K/Q at a trading firm, eventually becoming the human debugger for my team's K/Q "investment"' - that sounds so familiar to me lol, except it's my second year of using kdb in a trading firm, but still cannot run away from becoming a human debugger, and all I can use as a reference is code.kx.com.
  - jzwinck 11y ago
    Is code.kx.com your only resource because there's not much else written publicly in these languages, or is it because your employer blocks you from using other resources which are publicly available?
BWStearns 11y ago
Does anyone have a good resource on this family of languages or otherwise on any of them individually? Every time I've run across references to K/Q I've poked around a bit and it feels like they kind of exist as linguistic curiosities in some vacuum with a vaguely unexplained creation myth about a man named Whitney. Edit: found this paper which appears to be around the birth of array languages by the developer of APL. http://www.jsoftware.com/papers/tot.htm http://www.jsoftware.com/papers/tot.htm
boulos 11y ago
I enjoy the sudo of a non-https curl that copies this to /bin/k...
aplorbust 11y ago
I think http://kparc.com/lisp.txt http://kparc.com/lisp.txt would be easier for the HN crowd to digest. Better marketing. K is like Scheme but with vectors instead of lists. If you cannot handle the one character APL verbs, you can always sacrafice some resources and wrap them in verbosely named functions. Look at q/q.k
- nickpeterson 11y ago
  That is honestly quite helpful. I can't seem to find an actual link from the main kparc to that page. Any other hidden gem pages on that site?
riffic 11y ago
This is not an acceptable method of packaging, distributing, or installing software: sudo curl -u USR:PWD http://kparc.com/download/k http://kparc.com/download/k -o /bin/k;sudo chmod +x /bin/k
RodgerTheGreat 11y ago
Maybe this would be an appropriate place to drop a plug for iKe, a sandbox for writing interactive, graphical sketches in your browser using K: https://github.com/JohnEarnest/ok/tree/gh-pages/ike https://github.com/JohnEarnest/ok/tree/gh-pages/ike
deleted 11y ago
[deleted]
cousin_it 11y ago
For anyone wondering what K is, I'll repost this old email exchange between an ML person and a K person (it's already online, so no privacy violation): On Wed, 12 Oct 2005, Fermin Reig wrote: > Dear Rico, > > I have read Mark Joshi's book on C++ design patterns (as well as your > review) and I'd like to share my opinion of the book with you. (By the > way, I find the information in your website very useful.) > > My interest in the book was to try to learn how theory is put into > practise. The best way to do that is by actually implementing things, so > I did: I reimplemented his C++ code in OCaml, a functional, OO language > that I like using. However, instead of a direct translation of C++ > classes to OCaml classes, I chose a non-OO design. The result is quite > interesting from the point of view of code complexity and programming > productivity (and hence cost). Here's a summary: > > Monte Carlo (datatypes only) > C++: 264 lines of code (LOC), (7 classes, 20 methods), 12 files > ML : 33 LOC, (3 datatypes, 1 function), 2 files > LOC ML/C++: 33/264 = 13% > Binomial trees (datatypes only) > C++: 264 + 138 = 402 LOC, (10 classes, 30 methods), 18 files > ML : 33 + 12 = 45 LOC, (3 datatypes, 3 functions), 2 files > LOC ML/C++: 45/402 = 11% > Binomial trees (datatypes + main algorithm) > LOC ML/C++: 165/522 = 32% > > I'm not claiming that Mark's C++ code is bad (actually, it's quite > good). However, using a better tool results in obtaining a better final > product. (Performance of Ocaml's code is competitive with C++ as well.) > > I have written slides with more details about this, which I have shown > to a few friends. If you would like to see them, I can email them to > you. (I have also told Mark Joshi about my evaluation.) > > Regards, > Fermin Hi Fermin, Not bad. But my K implementation only uses 2 lines of code though... EuroOpt:{[S;K;r;v;T;n;po] / spot, strike, rate, vol, expir, steps, payoff / initialize constants p:(%2*m)*(1%D)-d:a-m:_sqrt -1+a*a:.5*(_exp dt*r+v*v)+D:_exp -r*dt:T%n; / apply n binomial steps :*n{-1_ D*(p*1!x)+x*1-p}/K po' S*(1%d)^(2*!n+1)-n } ...and here are some test cases... po:{0|x-y}; / arbitrary payoff function: max(0, K-S) for put / compare results for n = 16, 32, 64, 128, and 256 \t EuroOpt[5;10;.06;.3;.5;;po]' _16*2^!5 / pass in payoff functions for put, call, and digital \t EuroOpt[8;10;.06;.3;.5;500;]' {0|x-y},{0|y-x},{y>x} / investigating convergence for a digital option with 1-300 steps... EuroOpt[8;10;.06;.3;.5;;{y>x}]' 1+!300 So yes, I agree with you. Functional languages are cool and C++ is verbose & restrictive. Unfortunately, in the real world people don't care about any of this... :-) Cheers, - Rico And that was the previous version of K, before Q/kdb+. Things are probably even more concise now, but I've stopped following this about 10 years ago. Good times.
Chris2048 11y ago
What is K/KDB/Q/J like wrt concurrency?
- aet 11y ago
  Two processes can't write simultaneously to the same table partition.
alphapapa 11y ago
sudo curl -u USR:PWD http://kparc.com/download/k -o /bin/k;sudo chmod +x /bin/k No. No, no, no! Bad developer, bad!
- riffic 11y ago
  Not sure why a downvote was left without a comment but I'll upvote you and leave a comment that I wholeheartedly agree. This is not an acceptable method of packaging or distributing software.
  - alphapapa 11y ago
    Sometimes I feel like you are expected to check your sense of humor at the door here. :|
lolidaisuki 11y ago
>sudo curl -u USR:PWD http://kparc.com/download/k http://kparc.com/download/k -o /bin/k;sudo chmod +x /bin/k Is this targeted at web developers or something?
anonu 11y ago
Has anyone used kdb+ in a real-time, mission critical setup - where kdb+ is in the critical path? I am referring mainly to trading applications where kdb+ is in the critical path. Can it be used as a low-latency / high-throughput system, reliably?
- dintech 11y ago
  I know at least Bank of America and Marshall have/had this.
mathattack 11y ago
Interesting. 1010data was built on a version of K as well. Very fast computation, and a spreadsheet GUI to hide the language complexities.
jsgrahamusxxx 11y ago
Another K derivative is klong. I've communicated with the author and he is helpful and willing to fix things. Enjoy
treerex 11y ago
The symbolism implicit in the characters used in APL is lost with J/K/Q and any other ASCII variant. I highly recommend reading Ken Iverson's Turing Award Lecture too.
wrp 11y ago
K/Q is famous for extremely short code, but that is partly due to a misunderstanding of K/Q's nature. Sure, some things are expressed more concisely because you are operating on arrays rather than doing loops, but most of the conciseness comes from two other factors. First, there are syntacitc tricks to use fewer characters, e.g. single-character names and $[c;t;f] instead of IF-THEN-ELSE. But the big thing that most people ignore is that K/Q is a DSL. It is designed connect to a server, acquire tick data, and do time series analysis on clean numeric arrays. Stick to those operations and your code is amazingly short. If you expand the notation to something more readable and try doing more general programming tasks, the verbosity becomes about like Lua.
- icsa 11y ago
  IMHO, I would respectfully disagree. K/Q canbe used for all manner of software systems. PageRank can be done in a few lines of code - with clarity approaching the mathematical description. The solutions to the Advent of Code (http://adventofcode.com/ http://adventofcode.com/ and http://kparc.com/advent/ad.k http://kparc.com/advent/ad.k) are readily expressed/solved in k/Q. That said, it excels above other languages/systems at systems like real-time trading.

161 points by vonnik 11y ago

Has anyone looked at SciDB (http://www.paradigm4.com/ http://www.paradigm4.com/) as a replacement for KDB. Seems like it would fit the bill and has a community edition. I do see some usage in the financial markets.

payne92 11y ago

That looks like more of a grammar. A specification would describe, among many, many, many other things, how big an int is and what happens for overflow, etc.

baddox 11y ago
To be fair, those things could all be deliberately unspecified. Granted, the shortness of a language's spec is less impressive when it is simply the result of the language being woefully underspecified.
dang 11y ago
Ok, we changed the title from "The Complete Language Spec of K" to something less objectionable.

tlack 11y ago

So is the if syntax shown at the bottom coming to K or is that only for illustration? If not, why not use $[c;t;f] then?

RodgerTheGreat 11y ago
A good question. Older versions of K had if and while as syntactic sugar. You could always do without them by using cond and adverbs. K5 did away with these syntactic forms, and for whatever reason Arthur decided to put them back in k6.

wyc 11y ago

Why use such a thing? Array languages are very powerful for dealing with high-dimensional data. R, matlab, octave, and Julia can all do this and are satisfactory for most people. However, proponents claim that languages such as K are much more expressive. The APL family gets a bad rap for being "read-only", but I think it's mostly because they've fallen out of favor and have become unpopular. People who have experience working with these languages can encode/decode incredible amounts of information to/from a few lines once they see "phrases" and "sentences" instead of "my cat chewed the 56k modem line". We don't write Integral() in calculus when we want to take an integral, so why not have similar shorthands in computation? Here's the vocabulary of the sister language J for comparison: http://www.jsoftware.com/help/dictionary/vocabul.htm http://www.jsoftware.com/help/dictionary/vocabul.htm "The one-page thing": http://code.jsoftware.com/wiki/Essays/Incunabulum http://code.jsoftware.com/wiki/Essays/Incunabulum Naive K-Nearest Neighbors implementation: https://github.com/wyc/snippets/blob/master/j/knn.ijs https://github.com/wyc/snippets/blob/master/j/knn.ijs Community: https://www.reddit.com/r/apljk/ https://www.reddit.com/r/apljk/

minikomi 11y ago
A nicer to look at J Vocab has been published recently: http://code.jsoftware.com/wiki/NuVoc http://code.jsoftware.com/wiki/NuVoc It's a fun language to use to do /r/dailyprogrammer puzzles.

RodgerTheGreat 11y ago

Specifically, the reference card here is describing "k6".

nickpeterson 11y ago

How would one actually go about getting a username and password, I see these languages often, and know this is the true successor since Whitney is working on it, but i think all of these are neat. Or should I just learn Kona/kerf/xxl?

olympus 11y ago
tl;dr: I recommend learning J. If you just want to play around (no commercial use) you can download kdb+ from here: https://kx.com/software-download.php https://kx.com/software-download.php but you only get the 32-bit version for free, so keep your DB under 4 GB. With kdb+ you get K, the language, Q, which is a superset of K, and a column (time-series) oriented database engine. I recommend against using it, because if you want to do something meaningful (like make money somehow) then you need to buy a commercial license. I hear that they cost around $2k per machine (or possibly per core). Kona is nice but it is a full version behind K (Kona is a copy of K3, and kdb+ is on K4) and it isn't quite as fast/optimized. It's great if you are set on using K but don't have the cash and don't need database integration. Kerf (by the same guy who made Kona) has a friendlier syntax but seems to be commercially oriented similar to K (as in email us for free demo software but pay up when you want to do it for real). J is open source, free for commercial use, has some decent tutorials written for it, and even has a free database engine (JDB requires a license for commercial use, but Jd seems to be free for everything. It probably isn't as fast as K, but it has a nice feel to it. The runtime is under 3 MB and even with a Qt IDE and a bunch of extras it's under 30 MB. You can make Qt base GUIs with J and do quite a few things. I started learning J just last week and have been doing some problems on Project Euler to get familiar with it. I like it quite a bit. It even has built in functions for prime factorization, finding the prime number sieve, and and extended precision mode which makes solving some problems very easy.

ktamura 11y ago

While I really like K/Q/J/APL (some of this is Stockholm Syndrome: I spent the first 3 years of my career writing K/Q at a trading firm, eventually becoming the human debugger for my team's K/Q "investment". It got so annoying that I worked on a little parser library to help me debug: https://github.com/kiyoto/ungod https://github.com/kiyoto/ungod), they are doomed from a adoption/future viability point of view. 1. Steep learning curve without benefits: APLs like K/Q/J optimize for concision to the point of unreadability. Sure, it might be fun to decipher clever K/Q one-liners, but if you have to do it everyday for work in production, it's just exhausting. This lack of readability has limited adoption and the growth of its user community. For any technology is to have a viable community, it needs to be usable by a critical mass. K/Q in specific but APLs in general never had that, especially with more user-friendly alternatives like R/Matlab for scientific computing. 2. No open source community. There's Kona (https://github.com/kevinlawler/kona https://github.com/kevinlawler/kona) by Kevin Lawler, but again, its community has been small because the underlying language is not design to be usable by enough people. 3. Domain specificity of array languages: These days, array languages are just too limited in its scope. Scientific computing, the bread and butter of any array programming language, has been made possible in other languages (ex: Python), making array languages not powerful nor compelling enough to use because most of its strengths can be found in other languages and its weaknesses are too crippling. I heard that Arthur Whitney found his successors (a pair of Russian programmers from St. Petersburg, iirc), so K/Q will likely to be around beyond his retirement. That said, I think its user base will continue to shrink for above reasons.

f3lix133 11y ago
'3 years of my career writing K/Q at a trading firm, eventually becoming the human debugger for my team's K/Q "investment"' - that sounds so familiar to me lol, except it's my second year of using kdb in a trading firm, but still cannot run away from becoming a human debugger, and all I can use as a reference is code.kx.com.
- jzwinck 11y ago
  Is code.kx.com your only resource because there's not much else written publicly in these languages, or is it because your employer blocks you from using other resources which are publicly available?

BWStearns 11y ago

Does anyone have a good resource on this family of languages or otherwise on any of them individually? Every time I've run across references to K/Q I've poked around a bit and it feels like they kind of exist as linguistic curiosities in some vacuum with a vaguely unexplained creation myth about a man named Whitney. Edit: found this paper which appears to be around the birth of array languages by the developer of APL. http://www.jsoftware.com/papers/tot.htm http://www.jsoftware.com/papers/tot.htm

boulos 11y ago

I enjoy the sudo of a non-https curl that copies this to /bin/k...

aplorbust 11y ago

I think http://kparc.com/lisp.txt http://kparc.com/lisp.txt would be easier for the HN crowd to digest. Better marketing. K is like Scheme but with vectors instead of lists. If you cannot handle the one character APL verbs, you can always sacrafice some resources and wrap them in verbosely named functions. Look at q/q.k

nickpeterson 11y ago
That is honestly quite helpful. I can't seem to find an actual link from the main kparc to that page. Any other hidden gem pages on that site?

riffic 11y ago

This is not an acceptable method of packaging, distributing, or installing software: sudo curl -u USR:PWD http://kparc.com/download/k http://kparc.com/download/k -o /bin/k;sudo chmod +x /bin/k

RodgerTheGreat 11y ago

Maybe this would be an appropriate place to drop a plug for iKe, a sandbox for writing interactive, graphical sketches in your browser using K: https://github.com/JohnEarnest/ok/tree/gh-pages/ike https://github.com/JohnEarnest/ok/tree/gh-pages/ike

deleted 11y ago

[deleted]

cousin_it 11y ago

For anyone wondering what K is, I'll repost this old email exchange between an ML person and a K person (it's already online, so no privacy violation): On Wed, 12 Oct 2005, Fermin Reig wrote: > Dear Rico, > > I have read Mark Joshi's book on C++ design patterns (as well as your > review) and I'd like to share my opinion of the book with you. (By the > way, I find the information in your website very useful.) > > My interest in the book was to try to learn how theory is put into > practise. The best way to do that is by actually implementing things, so > I did: I reimplemented his C++ code in OCaml, a functional, OO language > that I like using. However, instead of a direct translation of C++ > classes to OCaml classes, I chose a non-OO design. The result is quite > interesting from the point of view of code complexity and programming > productivity (and hence cost). Here's a summary: > > Monte Carlo (datatypes only) > C++: 264 lines of code (LOC), (7 classes, 20 methods), 12 files > ML : 33 LOC, (3 datatypes, 1 function), 2 files > LOC ML/C++: 33/264 = 13% > Binomial trees (datatypes only) > C++: 264 + 138 = 402 LOC, (10 classes, 30 methods), 18 files > ML : 33 + 12 = 45 LOC, (3 datatypes, 3 functions), 2 files > LOC ML/C++: 45/402 = 11% > Binomial trees (datatypes + main algorithm) > LOC ML/C++: 165/522 = 32% > > I'm not claiming that Mark's C++ code is bad (actually, it's quite > good). However, using a better tool results in obtaining a better final > product. (Performance of Ocaml's code is competitive with C++ as well.) > > I have written slides with more details about this, which I have shown > to a few friends. If you would like to see them, I can email them to > you. (I have also told Mark Joshi about my evaluation.) > > Regards, > Fermin Hi Fermin, Not bad. But my K implementation only uses 2 lines of code though... EuroOpt:{[S;K;r;v;T;n;po] / spot, strike, rate, vol, expir, steps, payoff / initialize constants p:(%2*m)*(1%D)-d:a-m:_sqrt -1+a*a:.5*(_exp dt*r+v*v)+D:_exp -r*dt:T%n; / apply n binomial steps :*n{-1_ D*(p*1!x)+x*1-p}/K po' S*(1%d)^(2*!n+1)-n } ...and here are some test cases... po:{0|x-y}; / arbitrary payoff function: max(0, K-S) for put / compare results for n = 16, 32, 64, 128, and 256 \t EuroOpt[5;10;.06;.3;.5;;po]' _16*2^!5 / pass in payoff functions for put, call, and digital \t EuroOpt[8;10;.06;.3;.5;500;]' {0|x-y},{0|y-x},{y>x} / investigating convergence for a digital option with 1-300 steps... EuroOpt[8;10;.06;.3;.5;;{y>x}]' 1+!300 So yes, I agree with you. Functional languages are cool and C++ is verbose & restrictive. Unfortunately, in the real world people don't care about any of this... :-) Cheers, - Rico And that was the previous version of K, before Q/kdb+. Things are probably even more concise now, but I've stopped following this about 10 years ago. Good times.

Chris2048 11y ago

What is K/KDB/Q/J like wrt concurrency?

aet 11y ago
Two processes can't write simultaneously to the same table partition.

alphapapa 11y ago

sudo curl -u USR:PWD http://kparc.com/download/k -o /bin/k;sudo chmod +x /bin/k No. No, no, no! Bad developer, bad!

riffic 11y ago
Not sure why a downvote was left without a comment but I'll upvote you and leave a comment that I wholeheartedly agree. This is not an acceptable method of packaging or distributing software.
- alphapapa 11y ago
  Sometimes I feel like you are expected to check your sense of humor at the door here. :|

lolidaisuki 11y ago

>sudo curl -u USR:PWD http://kparc.com/download/k http://kparc.com/download/k -o /bin/k;sudo chmod +x /bin/k Is this targeted at web developers or something?

anonu 11y ago

Has anyone used kdb+ in a real-time, mission critical setup - where kdb+ is in the critical path? I am referring mainly to trading applications where kdb+ is in the critical path. Can it be used as a low-latency / high-throughput system, reliably?

dintech 11y ago
I know at least Bank of America and Marshall have/had this.

mathattack 11y ago

Interesting. 1010data was built on a version of K as well. Very fast computation, and a spreadsheet GUI to hide the language complexities.

jsgrahamusxxx 11y ago

Another K derivative is klong. I've communicated with the author and he is helpful and willing to fix things. Enjoy

treerex 11y ago

The symbolism implicit in the characters used in APL is lost with J/K/Q and any other ASCII variant. I highly recommend reading Ken Iverson's Turing Award Lecture too.

wrp 11y ago

K/Q is famous for extremely short code, but that is partly due to a misunderstanding of K/Q's nature. Sure, some things are expressed more concisely because you are operating on arrays rather than doing loops, but most of the conciseness comes from two other factors. First, there are syntacitc tricks to use fewer characters, e.g. single-character names and $[c;t;f] instead of IF-THEN-ELSE. But the big thing that most people ignore is that K/Q is a DSL. It is designed connect to a server, acquire tick data, and do time series analysis on clean numeric arrays. Stick to those operations and your code is amazingly short. If you expand the notation to something more readable and try doing more general programming tasks, the verbosity becomes about like Lua.

icsa 11y ago
IMHO, I would respectfully disagree. K/Q canbe used for all manner of software systems. PageRank can be done in a few lines of code - with clarity approaching the mathematical description. The solutions to the Advent of Code (http://adventofcode.com/ http://adventofcode.com/ and http://kparc.com/advent/ad.k http://kparc.com/advent/ad.k) are readily expressed/solved in k/Q. That said, it excels above other languages/systems at systems like real-time trading.