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22:38:21
pjb
vms14: it's easy. In the case of lisp sexps, eg. if: (if <test> <then> [<else>]) -> (defclass lisp-if (lisp-expression) ((<test> :initarg :test :reader if-test) (<then> :initarg :then :reader if-then) (<else> :initarg :else :initform nil :reader if-else)))
22:39:06
pjb
vms14: then: (defmacro my-sexpified-language:if (<test> <then> &optional <else>) (make-instance 'lisp-if :test <test> :then <then> :else <else>))
22:40:24
pjb
Having classes has the big advantage that you can write generic functions dispatching on them, to do all kind of stuff on the programs thus represented. You can generate them in different languages, compile them to lisp or native code, pretty print them, transform them, etc.
22:41:03
White_Flame
I find it often yields smaller, more manageable code to do the same thing with plain data structures and manual functions
22:43:01
White_Flame
but yeah, it's still a tool in the toolbox. Just don't go all Java "OO = Object Obsessed" ;)
22:44:46
vms14
I don't see many advantadges using CLOS instead of just functions transpiling directly to what I want
22:45:53
pjb
vms14: the advantage is instead of having a procedural style, you can have a data driven style, where you have an internal representation of the program you want to generate. So you can manipulate it.
22:49:10
pjb
Instead of hardcoding stuff such as: (php-if (php-equal (php-var "a") (php-integer 0)) (php-function-call (php-function "foo") (php-var "b") (php-integer 42))), you can have some data |# (let ((php-code '(if (= a 0) (foo b 42)))) #| and process it: |# (generate (parse-php-sexp php-code)))
22:50:47
vms14
I had this (defun php-if (test &rest statements) (format nil "if(~a){~{~a~}}" test statements))
22:52:37
vms14
I'll think about writing an AST, because I'd like to learn more about compilers and metaprogramming
22:53:09
pjb
(case (first sexp) ((if) (format …)) ((= /= + - * / …) (format …)) (else #|mustbe funcall|# (format …)))
22:54:47
pjb
Or, you could (defgeneric (op &rest args) (:method ((op (eql if)) &optional then else) …) …)
22:58:11
vms14
the heredocs are because I wanted "" for the html and variable interpolation, but they make the code even uglier
23:22:55
HiRE
could someone provide me a few links of github repos or whatever with really well written modern CL code?
23:23:57
mason
HiRE: There are books worth reading. Here, for example: http://www.gigamonkeys.com/book/
23:24:40
HiRE
thanks Xach. Reason I ask is I'd like to take on a project to write a simple DNS server in CL for my own use.
23:28:01
HiRE
Xach, I'd love to take a look. One thing I was beginning to look at was even how to get started reading/writing packets in CL
23:28:37
pjb
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjU-KCOn4TnAhWRERQKHcS8Ad0QFjAAegQIAxAB&url=https%3A%2F%2Fgithub.com%2Ffjames86%2Fdragons&usg=AOvVaw15yBgmePwcAl1LunaxgUGy
23:28:38
pjb
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahUKEwjU-KCOn4TnAhWRERQKHcS8Ad0QFjABegQIBxAB&url=https%3A%2F%2Fgithub.com%2Fhanshuebner%2Fans&usg=AOvVaw3Foqv4BPm4Ihcr1iFJB68t
23:28:50
HiRE
mason, that was my initial idea but I'd like to keep it pure CL if possible. I really like CL and FFI seems like a last ditch effort for me.
23:30:12
Xach
*.asd files are input to a program that can compile and load multiple files in the right order
23:31:41
Xach
for typical lisp development you start with a running intractive system and then teach it new things to do
23:32:23
HiRE
oh I see. So instead of having to load a buffer complete in say SLIME you use *.asd to help suggest it stuff?
23:33:15
Xach
HiRE: no. more like someone says "i have a library that does X" and you get that library, the system can use the *.asd file to load that library
23:33:44
Xach
and if that library needs a library that does Y, the *.asd files arranges to load that first too
23:34:32
Xach
quicklisp is a program that handles that error and downloads libraries to make them available to load
23:35:36
HiRE
oh sweet, yeah found the website. Seems like a package manager similar to NPM or something
23:42:06
Xach
i wrote that dns client because i had a web service that fetched images from the web, and i wanted things arranged so that things wouldn't get hung up by DNS or TCP timeouts
23:43:34
HiRE
Xach, I want to write one to help get around the DNS hijacking going on by my ISP lol.
23:44:43
Xach
maybe these things drift offtopic...we can discuss it via private messages if you're inclined.
23:45:19
Xach
i used to work at an ISP, and i know a little about networking, so it is interesting to me.
2:36:46
no-defun-allowed
A lot of things in Common Lisp can have documentation strings, so you probably should be reminded by them in other languages.
2:37:19
no-defun-allowed
To generate a document with all the documentation strings, Staple <https://github.com/Shinmera/staple> could be used.
2:41:33
White_Flame
what's the proper term for a symbol's value binding outside of any dynamic binding scopes? global value, toplevel value, etc?
3:20:37
pjb
"eternal" would be a dynamic (time) notion, but it implies some level of immutability, so it would do only for defconstant…
3:20:51
White_Flame
The length of time is a scope with a definite beginning and usually definite ending
3:21:17
White_Flame
"global" means many things, and the binding in question is the shared one that everybody sees without a local private override
3:21:34
no-defun-allowed
SBCL has a macro named DEFGLOBAL, so there is some precedent to calling it a global value.
3:22:31
pjb
White_Flame: defining a variable with defparameter or defvar doesn't propagate its definition in the past. Therefore it cannot be a "global temporal" scope.
3:23:37
White_Flame
the scope is the distinction between this one and private bindings that other threads of execution create
3:27:29
White_Flame
but I did default to "global" as well, just couldn't find any specific basis for it
3:28:01
HiRE
I think its just the names of the scope. The process is intuitive but "dynamic" goofs me up for some reason.
3:28:32
Bike
the clhs entry for defvar/defparameter calls it the "value cell" but that's kinda bad for other reasons
3:28:37
pjb
If you use the same word for the two orthogonal notion, you are bound to be confused, and to confuse everybody.
3:29:03
White_Flame
and does the "value cell" point to a private location when another dynamic binding is in effect?
3:36:59
White_Flame
" A dynamic variable can be referenced outside the dynamic extent of a form that binds it. Such a variable is sometimes called a ``global variable'' but is still in all respects just a dynamic variable whose binding happens to exist in the global environment rather than in some dynamic environment. "
3:44:22
White_Flame
well, specific to the comment I'm writing, "global value" would imply the value held in symbol's said "global binding", even if there are other dynamic bindings flying around
3:48:22
White_Flame
oh, and "global variable" is in the glossary as well: "global variable n. a dynamic variable or a constant variable."
6:14:29
smokeink
how to muffle such notes? note: doing unsigned word to integer coercion (cost 20) to "<return value>"
7:14:50
White_Flame
I have a macro that generates `(locally (declare ....) ,@body) so I can easily wrap it around small operations
7:15:43
White_Flame
(declare (sb-ext:unmuffle-conditions optimization-note)) around the parameters of the subform also allows its whinings to not be muffled, just the singular form in question
8:41:49
trittweiler
White_Flame, "global binding" versus "thread-local binding" (non-standard, of course) versus "local binding" is decent terminology I would reckon
8:44:48
jackdaniel
isn't the terminology: deep binding and shallow binding (and a symbol value which is not a binding)?
8:46:14
jackdaniel
and a consequence of deep binding implementation technique are thread-local bindings, and shallow gives you bindigns which are shared across threads (n.b probably harder to synchronize )
8:51:17
beach
jackdaniel: The distinction between deep and shallow binding is just an implementation issue.
8:52:34
beach
jackdaniel: Correct implementation of shallow binding in a multi-thread context is that there must be a per-thread "value cell".
8:54:06
beach
From memory, SBCL assigns a number to a symbol as soon as it is used as a variable. This number is used as an index into a table in the reified thread.
8:54:12
jackdaniel
hm, thanks for correcting me. I'll re-read the relevant parts of LiSP then to improve my understanding
9:07:35
jackdaniel
sorry, I can't tell from top of my head (and I'm focused on McCLIM issue atm so I'm not eager to look up ECL's internals code)
9:09:07
jackdaniel
I think that the location is on the stack and the array element is updated to point at that location
9:10:49
beach
But I wasn't asking what happens when a binding is done or undone. Just what SYMBOL-VALUE does. Again, if you are busy, you don't have to answer.
9:15:57
beach
For what it's worth, my current hypothesis is to use deep binding for SICL. I.e., the dynamic environment stack contains binding entries, and there is no per-thread table. SYMBOL-VALUE then has to search the stack to find the most recent binding.
9:16:50
beach
So searching for the current value or setting that value is more expensive than with shallow binding, at least if the stack is somewhat deep. Though finding the table in the thread is not free either.
9:17:30
beach
On the other hand, binding/unbinding is cheaper in deep binding than in shallow binding.
9:19:00
beach
If it turns out that 1. Access to special variables is frequent, and 2. Those accesses are often to deeply nested bindings, then I may have to reconsider.
9:28:19
White_Flame
beach: in SBCL, the TLS is always in a register, so "finding the table in the thread" actually is free
9:30:46
LdBeth
currying is just a function (defun currying (fn) (lambda (x) (lambda (y) (funcall fn x y))))
9:36:19
beach
It is *so* inspiring to answer questions from someone who 1. does not acknowledge this fact, and 2. leaves instead.
9:42:01
phoe
beach: the channel is logged, so if they ever come again and/or ask again, you can point them towards the logs in the channel topic.
9:43:18
jackdaniel
"- hey, I remember your nick from 5months ago, you did not thank me - do you remember that? - no (leaves the channel)", pretty burdensome strategy
9:44:04
jackdaniel
and I doubt that would change the culture of a person who is reminded that they did not follow proper netiquette
9:45:44
phoe
I thought of something like more like "oh I happen to recognize that nickname, they asked a question that was answered but they left, the answer is in the channel logs"