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I use to program financial applications in K/Q for a stint. Very elegant and orthogonal language. And very well documented. One major issue I had with it and ot

I use to program financial applications in K/Q for a stint. Very elegant and orthogonal language. And very well documented. One major issue I had with it and other APL-ish languages: lack of skimmability. I can easily skim thousands of lines of Perl and Java in seconds and have a rough idea of what the code does. Reading K, however, requires careful and deliberate attention to every single character. I found it useful to maintain documentation on how to /read/ the code (almost a literate programming approach).

BiteCode_dev 7y ago
That's bad in my book. I write a line once for a 100 times I read it.
- Roboprog 7y ago
  OTOH, there is something to be said for reading fewer lines in some cases. Conifer forest Vs Pine Pine Cedar Spruce Pine Cedar ...
  - threatofrain 7y ago
    Isn't Lisp that Conifer forest.
oddthink 7y ago
Yeah, I agree. I wrote some mortgage prepayment models in q for a while, but didn't dip into K itself. Q is fantastic as a database query language (assuming you have time-series databases and are mostly doing fairly simple operations.) Implementing a full model in it is fine, but can get hard to maintain. Also it has (or had, maybe they fixed it) a bunch of weird quirks, like "sum foo" skipping all the NAs in a list while "+/foo" didn't, resulting in NaN. (Or maybe it was +/ over an int array didn't work while a double array did. I forget.) Arrays of dicts were immediately turned into tables, which didn't work the same as an array of dicts, etc. But, yeah, it's not crazy implementing things in q/K, as long as they're mostly linear things. Trees are hard, iterative methods are hard, and it's really hard to skim code, other than to just rely on names and comments.
- ectoplasmaboiii 7y ago
  I believe they have fixed it. I just did the following: q)a: 1 2 3 0N 3 4 q)sum a 13 q)+/[a] 13

BiteCode_dev 7y ago

That's bad in my book. I write a line once for a 100 times I read it.

Roboprog 7y ago
OTOH, there is something to be said for reading fewer lines in some cases. Conifer forest Vs Pine Pine Cedar Spruce Pine Cedar ...
- threatofrain 7y ago
  Isn't Lisp that Conifer forest.

oddthink 7y ago

Yeah, I agree. I wrote some mortgage prepayment models in q for a while, but didn't dip into K itself. Q is fantastic as a database query language (assuming you have time-series databases and are mostly doing fairly simple operations.) Implementing a full model in it is fine, but can get hard to maintain. Also it has (or had, maybe they fixed it) a bunch of weird quirks, like "sum foo" skipping all the NAs in a list while "+/foo" didn't, resulting in NaN. (Or maybe it was +/ over an int array didn't work while a double array did. I forget.) Arrays of dicts were immediately turned into tables, which didn't work the same as an array of dicts, etc. But, yeah, it's not crazy implementing things in q/K, as long as they're mostly linear things. Trees are hard, iterative methods are hard, and it's really hard to skim code, other than to just rely on names and comments.

ectoplasmaboiii 7y ago
I believe they have fixed it. I just did the following: q)a: 1 2 3 0N 3 4 q)sum a 13 q)+/[a] 13