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13:57:12
scymtym
elderK: for working with vectors of octets, you may find https://github.com/sharplispers/nibbles and https://github.com/scymtym/utilities.binary-dump interesting (if you haven't found them already)
13:58:40
pjb
elderK: or: com.informatimago.common-lisp.cesarum.ascii or com.informatimago.common-lisp.data-encoding.data-encoding etc.
13:59:44
didi
pjb: I worry about the behavior of mathematical functions when fed infinities. For example, do all SIN functions return the same value when fed infinity?
14:02:29
pjb
I would say, just define a proper type hierarchy for sets of numbers + infinity and sets of infinities, and define proper arithmetic operations on them.
14:04:22
pjb
This library can use NAN infinities for infinite decimals if they are available but it would use other representations if not, and it would have to have integer and real infinities too, (and I'd assume complex infinities).
14:12:17
pjb
for cl:short-float : Intel's new Bfloat16 floating-point format: 8 bit exponent, 7 bit mantissa [pdf] <https://software.intel.com/sites/default/files/managed/40/8b/bf16-hardware-numerics-definition-white-paper.pdf>
14:13:01
pjb
oops! nope. short-float must have at least 13 bits of mantissa, and can go down 5 bits exponents.
14:17:26
Bike
sine is a periodic function with a rank of [-1, 1]. it would be pretty weird if sin(inf) = inf.
14:22:33
Bike
it seems like the magnitude does increasing as you get off the real line, so maybe it actually is infinity on a riemann sphere or something.
14:25:38
elderK
Reading "binary-type" right now. Nice code. But the defmacro part for define-binary-record and stuff is pretty crazy
14:26:05
elderK
I mean, they obviously knew what they were doing, far more than I do. But, I could have tried to break the macro down. It's this gigantic thing.
14:26:21
pjb
Bike: for complex, just revert to the fundamental formula: 1+e^ip=0, therefore sin(x)=(e^ip-e^-ip)/2i
14:27:14
pjb
By the way teaching maths is also done very badly. If you started by teaching complex numbers and 1+e^ip=0, you could cover 4 years of elementary maths in one semester…
14:31:20
pjb
elderK: that said, the indenting conventions of CL makes it very possible to use proportional fonts for its sources (there's very little inner alignment if at all).
14:31:50
pjb
elderK: so lines that have more than 80 characters, can still be within reasonable width when displayed in a nice proportional font.
14:33:35
pjb
For example (frame-font) -> "-*-Bodoni 72-normal-normal-normal-*-17-*-*-*-p-0-iso10646-1"
14:34:01
makomo
pjb: re: learning a language: i do that as well. learn the little elements and the means of composition and voila
14:34:06
makomo
i don't like learning language features by "pattern matching", i.e. reading examples. reading the whole spec/reference of the thing is always the best
14:34:28
makomo
but one thing that requires lots of examples (i.e. reading lots of code) is developing a style and learning the idioms/conventions
14:35:26
pjb
(now, some symbols represent several concepts, such as function type etc, and some concept are not precisely represented by one single symbol, but learning 2 CL symbol a day should let you cover it all in one year).
14:35:53
pjb
So, with such a proportional font, you can easily pack twice the characters in the same window width!
14:42:02
elderK
As for line length, it's actually pretty important to me. I have extremely poor eyesight, text is usually large. 80 characters per line, fits pretty well. But not more than that.
14:43:51
elderK
Great. That would be too tiny for me to read. Unless I was at an extremely low resolution.
14:44:30
elderK
Back when 800x600 was the norm, I used to use the DEC Terminal font. It was nice. Unfortunately, at higher resolutions, that font stops being feasible. It makes me sad. It was a great font.
14:44:39
pjb
elderK: use (with-open-file (source "foo.lisp") (let ((*print-right-margin* 72)) (loop for sexp = (read source nil source) until (eq sexp source) do (pprint sexp))))
14:46:32
pjb
elderK: put (defun pp-list-source (file) (with-open-file (source file) (let ((*print-right-margin* 72)) (loop for sexp = (read source nil source) until (eq sexp source) do (pprint sexp))))) in your rc file, and use it in the repl to list the sources.
14:47:36
pjb
elderK: it's just a Q&D proof of concept of course. You may write better tools to help you.
14:48:13
elderK
I still have a lot to learn in that department regarding formatting of Lisp expressions.
14:49:27
elderK
One thing I'd like to know, is how to format long parameter lists. Or, the parameter list of a defun where the function name is pretty long, and the parameters wont fit on the same line.
14:51:06
elderK
:) I guess in time I'll develop a personal style to make it... sane for me. It's like conventions I follow when writing C, a lot of people hate it. But for me, they're vital for reasons mentioned above.
14:52:05
elderK
pjb: Aye. That's what I figured, but then you need some way to make the lambda list clear, that it IS the lambda list. Of course, anyone reading Lisp regularly will be able to tell that right away.
14:52:07
pjb
If the parameter list is long, you can put a newline between each parameter (and even add a 1-semi-color comment after each paramete).
14:53:20
elderK
I figure the lambda-list would be four spaces in, rather than the two for a usual body.
14:54:35
pjb
or keep using vi, and use 1,$|indent with: https://github.com/informatimago/bin/blob/master/indent
14:56:20
pjb
Well, indent is not a filter,you'd have to modify the script to make it a filter, which would allow you to re-indent only parts of your buffer.
14:58:16
elderK
Perhaps this is something I can contribute. An improved Lisp-indentation script for Vim :P
15:00:02
pjb
So, yes, read them, recover and document the indentation rules as specification, and implement them in vim or even in CL.
15:00:31
makomo
elderK: i started off with Vim first and used it for some time. i liked the concept of modal editing very much. then i found out about emacs but couldn't get myself to stick to it because of its non-modal defaults
15:00:35
elderK
I mean, the popular editors people use today seem to be stuff like Atom and stuff. And those have SLIME interfaces. Those people will have to manually indent, too, unless their "indenters" are more powerful or featureful out of the box than Vims.
15:01:36
makomo
Spacemacs is an emacs "configuration pack", i.e. a "ton" of Emacs Lisp that configures a lot of stuff for you out of the box. Spacemacs in particular configures Vim keybindings and "Evilifies" a lot of modes for you
15:02:26
makomo
i would say that the vim part of spacemacs is its best feature. it combines the power of modal editing with the power of emacs' extensibility (emacs lisp)
15:04:05
makomo
you can switch back to "emacs editing mode" (and back to "vim editing mode") at any time with a keybind
15:04:43
elderK
makomo: How about the other... stuff. Like say, sending stuff to the REPL or whatever. Do you find yourself having to use say, "Vi ish" keybinds for actual editing vs. Emacs-ish ones for the rest?
15:05:02
elderK
Like, maybe it seems dumb but I want to spend my time learning and experimenting with CL, not with Emacs.
15:05:51
makomo
elderK: that's exactly the problem that Spacemacs tries to solve. not only does it have vim keybinds for editing, but it also tries to configure vim-like keybindings for other "modes" (a mode in Emacs is what a filetype is in Vim, or at least that's the comparison i've heard)
15:06:03
elderK
Maybe Emacs is one of those "Dentist-like" things. It's really not so bad. It seems like this huge thing to get used to, but it's probably not so bad.
15:06:25
makomo
sometimes it happens that you'll have to configure a certain mode yourself, i.e. set up the vim-like keybindings for it yourself. but most of the popular stuff Spacemacs already handles for you, so it's very easy
15:07:35
makomo
elderK: i'm not sure how long it took, but assume a few weeks or something (i guess?)
15:08:10
makomo
elderK: yeah, it's not that bad, especially with Spacemacs around now. i'm not sure if i would have switched if it wasn't for Spacemacs, heh
15:09:06
makomo
some people say you shouldn't start with Spacemacs as it'll hide the vanilla behavior of Emacs from you and make it harder to understand stuff, etc. while that's true to some degree, i think the benefit of Spacemacs are much larger than that drawback
15:09:39
esper0s
i have been using emacs for a year now, loving it but oh my god the random buffer popping up is hideous
15:11:04
makomo
elderK: also, the drawback isn't that hard to overcome anyway. it's always the same -- rtfm. :-) read emacs' manual, read spacemacs' manual and see what exactly is the vanilla behavior and what new concepts spacemacs introduced
15:11:56
makomo
elderK: for example, emacs has the notion of a "package", but spacemacs introduces the notion of a "layer" which is a logical grouping of packages that are meant to be used together or are somehow logically connected
15:12:32
makomo
elderK: to install an emacs package you would use emacs' own commands, but to install a layer you would use spacemacs' commands
15:34:33
pjb
elderK: yes, and similarly, don't spend your time customizing vim. Instead, write your own environment and editing tools in Common Lisp. You can use portable Hemlock as basis, or start from scratch.
15:34:43
pjb
elderK: Have a look at https://www.informatimago.com/develop/lisp/com/informatimago/small-cl-pgms/sedit/index.html
15:37:57
jcowan
and likewise cos and tan; arcsin and arccos return #C(nan, nan), but atan(inf) is, bizarrely, 1.5707963267949.
15:42:50
esper0s
thank you for the links the second book about text editors was god send as iam now writtin a text editor
15:46:42
esper0s
no iam alright with it, i have not started it yet as iam making a library of ansi ascape sequences first
15:48:29
jcowan
I have concluded reluctantly that my editor (if/when I get to it) will have to have a few ANSI escapes, though I had hoped to make it pure TTY interaction
15:49:25
jcowan
I'm trying to hold it down to "up" and "reverse video" on a few characters (to show that they are not literal)
15:53:12
pjb
How to represent buffers is less important than to define a good interface to this abstraction. You can change the implementation later.
15:59:38
jackdaniel
its core runtime is in the C world, so it is easy to interoperate with software knowing how to deal with C ABI both ways
15:59:44
pjb
one strong point of ecl is that it has a libecl.so library so you can generate unix executables that are as small as C executables. Also, you can embed it in C applications.
16:01:13
esper0s
so basically you can right applications in ecl and run tose applications with a c compiler like gcc?
16:02:07
jackdaniel
jebes: wrong, clasp compiles to llvm (it is interesting but it has different qualities which make it interesting)
16:02:38
jackdaniel
esper0s: ecl has a compiler which compiles to c and then runs a c compiler on that for you, no need to do it by hand
16:04:07
jackdaniel
another interesting feature is that you may have Android applications which utilize ECL (see project eql5-android for examples)
16:09:14
elderK
I imagine being good at programming is less about the language, and more about the concepts and stuff you have to leverage. So, sure, you can be a good C programmer. Of course, as with human languages, the language you speak can influence how you think. So, some things that work really with in C, the C way, obviously do not translate well to say, Lisp. And vice versa.
16:09:28
elderK
But learning both, gives you access to more concepts and ways of thinking, which hopefully makes you a better programmer.
16:10:04
jackdaniel
having access to more convenient tools may prove fatal if you need to write later in a language which doesn't provide them
16:12:17
esper0s
exactly, iam just using c as a medium to become a better programmer, as i like embedded systems and those are mostly implemnted in c, also iam very diasspointed with university, they have been teaching us 7 languages and havent gone deep to any of those
16:12:50
esper0s
the language is just the syntax, but learning to represent concepts is the tricky part
16:12:52
jackdaniel
university is not for teaching you anything, only to show you directions in which you may teach yourself
16:14:35
minion
esper0s: please see SICP: The Structure and Interpretation of Computer Programs, a CS textbook using Scheme. Available under the CC-BY-NC Licence at <http://mitpress.mit.edu/sicp/> (HTML), <http://www.neilvandyke.org/sicp-texi/> (Texinfo), and <http://twb.ath.cx/ebooks/sicp.pdf> (PDF). Video lectures are available under the CC-BY-SA licence at <http://swiss.csail.mit.edu/classes/6.001/abelson-sussman-lectures/>
16:15:06
jackdaniel
this book is in scheme, but also covers many important subjects in programming and computer science
16:15:57
jackdaniel
studying either of these books will make you certainly a better programmer than you'd become if you had only followed assignments without expanding your knowledge
16:16:49
jackdaniel
I've said, that following assignments is not enough, not that it is unnecessary, make no mistake
16:17:03
esper0s
a terminal application to practice touch typing, a text editor and a dynamic interface to change the termios driver attributes
16:18:23
elderK
esper0s: A major issue I find is that no matter how much information you may read, how much code you study in a day, there's only so much of it that the brain can reliably digest and get something out of.
16:18:51
jackdaniel
as of embedded systems, as a former embedded systems engineer I can tell you without a doubt that low resource systems are a past
16:19:12
jackdaniel
it is simply cheaper to build toasters on arm chips than using atmega chips and similar
16:19:38
elderK
It's like Math. You can study Math, and do lots of practice. You need to to really nail the concepts. But, unless you periodically refresh it, it's going to decay. You might not forget it entirely - but it will definitely rust.
16:20:30
esper0s
so you mean to say that the way embedded systems is going the industry might choose to adopt different a different language as a standard?
16:20:35
makomo
whew, imagine connecting to your microwave that's running CL using SLIME from emacs :-D
16:34:22
elderK
Guys, any tips on how to approach the understanding of this macro? https://github.com/frodef/binary-types/blob/9ec42042a50403961c08179a892ae3de725b1d7a/binary-types.lisp#L545
16:37:10
trittweiler
elderK, look at usage examples, use an interactive macroexpander and annotate pieces of the code with calls to FORMAT to see in what steps the expansion is computed
16:37:12
elderK
I mean, I understand that if say, he split the functionality out into separate functions... just to make them smaller, easier to understand in and of themselves, he'd probably have to hand a bunch of extra parameters to stuff. AND make sure that they're around at compile-time / load-time, etc.
16:38:20
pjb
elderK: you know, you're not the first one to have those problems. They have been solved! in emacs.
16:41:19
pjb
elderK: ok, there's a solution: (defun pp-list-source (file &optional (*print-depth* nil)) (with-open-file (source file) (let ((*print-right-margin* 72)) (loop for sexp = (read source nil source) until (eq sexp source) do (pprint sexp)))))
16:42:26
pjb
but indeed, it'd be better to implement a little function that would allow you to hide or show each subexpression at will.
16:44:11
pjb
elderK: yes, slowly, write tools and commands to build up and customize your environment.
17:27:44
elderK
So, I'm slowly managing to understand it. Just by reading it... Force of will and all that.
17:27:57
elderK
It's made harder because it seems that he's used tabs in his source. But, inconsistently.
17:34:59
elderK
I mean, it's nice code and all. The majority of it is pretty nice. Just, iono, it gives me something to think about. Like, now that I'm starting to understand the ins and outs of his define-binary-struct macro, I'm thinking: Could this be written in a way that is clearer or easier to read?
17:35:29
elderK
Over the past few months, I've been spending a lot of time reading code. I wouldn't say I've spent more time reading than writing but I've definitely upped the amount of time I spent reading "foreign" code.
17:36:20
elderK
:P I've started telling my tiny group of friends that they should try and read code as much as they write it so that they like... develop a sense of what's hard to read, and what isn't and so on.
17:36:44
elderK
I /should/ be working on sleep. But, iono, I feel oddly compelled to keep reading. :)
17:56:49
jebes
with the direction the IT industry is going, we just need to rebrand it as something else
18:26:38
jackdaniel
Java is a decent language. it is not CL, but isn't as bad as people try to shame it
18:27:59
jackdaniel
as of name of a common lisp for wide audience, we should call it "Not a Common Lisp" and claim that it has been developed by "The average Joe programmer"
18:30:21
jcowan
The R2RS report on Scheme was subtitled "An Uncommon Lisp". A stupid piece of snark IMAO, and I'm glad we dropped it.
18:31:44
elderK
Interesting. CLHS says that unless you specify :read-only nil as a defstruct slot option, it's implemention-defined whether or not there'll be a setf expander for it.
18:37:56
elderK
This really does seem kind of.. confusing: http://www.lispworks.com/documentation/lw70/CLHS/Body/m_defstr.htm
18:38:03
jcowan
The sentence "When this option is false or unsupplied, it is implementation-dependent whether the ability to write the slot is implemented by a setf function or a setf expander" has a bad ambiguity in it
18:38:09
elderK
Early in the description, it states that it creates readers for the slots, and they are setfable
18:38:38
elderK
Then later it says if you don't specify :read-only, or give it a falsey value for :read-only, it's implementation defined whether the slots are setfable.
18:38:58
jcowan
I read it as meaning that an implementation may use a setf function or a setf expander, whereas you are reading it as if it ended in "... or not".
18:39:43
elderK
I thought like, if you wanted to do (setf (something) value), you had to have a setf expansion?
18:40:13
pjb
elderK: setf can work in other ways than with a setf function or a defsetf or setf expander.
18:40:17
jcowan
On my reading, it doesn't say that setfability is optional, it says that the means of providing it (function or expander) is up to the implementation. But I agree that it's badly drafted.
18:40:50
pjb
elderK: this is a door open to let implementation optimize structures in very special ways.
18:41:26
pjb
Some old implementations took advantage of it. Modern implementations tend to define structures as subclasses of clos objects.
18:41:28
makomo
elderK: a "setf function" and a "setf expander" are just two ways of providing a "place" for SETF to operate on
18:43:52
elderK
So, as long as you are able to (setf (struct-slot ...) ...), it's just saying how you manage to provide that ability is open.
18:45:02
elderK
I have now learned that if you create a macro, you really should define the grammar of that somewhere so people can see exactly how it is to be used, just like CLHS does for say, defstruct or defclass. :D
18:45:40
elderK
It's not really doing anything all that complicated, not really. Just, very... clumped together.
18:45:46
makomo
or if the macro is simple enough, a couple of examples with their expansions or something
18:46:07
elderK
And ideally, you'd have all of those figured out before you started writing the macro, anyway.
18:46:29
elderK
I get the feeling that the binary-types stuff was intended to support more stuff originally, or in the future, but was never... fully completed.
18:48:09
elderK
Or rather, the goalpost changed. It is complete. But there are signs that it was meant to do more.
19:02:24
elderK
Question: If a macro is meant to evaluate one of its arguments, does it have to call eval on it?
19:03:11
makomo
elderK: good question. you're referring to evaluating the argument whilst computing the expansion, right?
19:03:39
makomo
(instead of arranging for the argument to be evaluated within the generated expansion)
19:03:49
elderK
I think so, yes. I'm not entirely 100% sure what I'm asking. I just know that some macros say "The argument is not evaluated" and others say "The argument is evaluated in the environment active at the time the macro was called."
19:04:01
pjb
elderK: no it doesn't have to evaluate, but ensure that the argument is evaluated at run-time.
19:04:26
makomo
elderK: you're thinking of the latter then. the former would be macroexpansion-time evaluation, which is a rare thing to do
19:04:29
pjb
elderK: in general it would be difficult to evaluate something at macroexpansion time, because EVAL doesn't take an environment argument.
19:05:32
elderK
Interesting. So, "argument is not evaluated", is that the same as just... splicing it directly into the expansion somehow? Or do you splice in the argument, quoted?
19:05:35
pjb
elderK: so the only case where you would "evaluate" something at macroexpansion time, would be when that something would be a macro or symbol-macro and you would 'evaluate" it by macroexpanding it.
19:06:34
pjb
(defmacro set-double (var expression) "evaluates the expressions and binds the resulting value to the variable var" `(setf ,var ,expression))
19:06:43
pjb
(defmacro set-double (var expression) "evaluates the expressions and binds the resulting value times 2 to the variable var" `(setf ,var (* 2 ,expression)))
19:06:56
elderK
Okay, and if the argument /is/ evaluated, you mentioned you'd arrange to /have/ it evaluated at the right time. How would you go about doing that? Would you create some gensymed variable somewhere and say, hey, evaluate this at whatever time, and use this gensym when referring to the "argument"?
19:07:36
makomo
what pjb just described is the case when the arguments /are/ evaluated (by arranging for them to be evaluated within the expansion)
19:07:44
pjb
Here, since ,var is in a place position in the setf form, it's not "evaluated" as such (it's evaluated as a place by setf). But since expression is expanded in a position that is evaluated by setf, then set-double has fulfilled its contract.
19:08:18
makomo
elderK: to "arrange for something to be evaluated" means to splice it into the proper places within the expansion
19:08:39
elderK
Okay, and to have it /not evaluated/ would mean to splice it in, but make sure it's quoted when spliced?
19:08:57
pjb
Basically, standard special operators and macros define what argument is evalauted and when, and what are not. And function calls evalutes all its arguments.
19:09:35
pjb
So macros can use their own parameters in those different ways, by putting them in forms using those special operators and macros or fucntion correspondingly.
19:10:51
elderK
Aye, but what's to stop them giving us some (make-symbol ....) thing? In that case, we are relying on LET not evaluating the names, right?
19:11:16
makomo
elderK: if they do so, the expansion will be incorrect, as the NAME will be the actual form (MAKE-SYMBOL ...)
19:11:35
elderK
For argument sake, let's assume LET itself is a macro and expands to something else, maybe a lambda or something, who knows. Then the name would be expanded into a lambda list. And that's where the error would be caught, no?
19:12:43
elderK
So, basically, whether or not something is evaluated or not, really depends on 1. We quote it when we create our expansion like ',name. OR it depends on what operators we use with that spliced argument.
19:13:09
pjb
(defmacro let ((&rest bindings) &body declarations-and-body) `((lambda ,@(mapcar (lambda (x) (if (listp x) (first x) x)) bindings) ,@declaration-and-body) ,@(mapcar (lambda (x) (if (listp x) (second x) nil))))) ; more or less
19:13:17
makomo
elderK: perhaps. what if you pass in an expression that is something like (&optional hi) and the LET macro splices its arguments? you might actually get a valid lambda list :-)
19:13:49
White_Flame
elderK: the way I normally state it is that macros take source code and return source code. If your macro foo is called as (foo a b (bar baz)), it gets the _source code_ forms A, B, (BAR BAZ). Any values associated to those probably don't exist, unless you're very particular in your build to assure some (usually global) values exist at compile-time
19:13:49
elderK
pjb: I appreciate you trying to help but code dumps like that in IRC are not all that helpful.
19:13:58
makomo
elderK: but yes, hopefully the error would be caught somewhere (either in the expansion (at run-time when the code is run) or the macro itself would catch it by doing some analysis)
19:14:05
pjb
(defmacro let. ((&rest bindings) &body declarations-and-body) `((lambda ,@(mapcar (lambda (x) (if (listp x) (first x) x)) bindings) ,@declarations-and-body) ,@(mapcar (lambda (x) (if (listp x) (second x) nil)) bindings))) (macroexpand-1 '(let. ((a 1) (b 2)) (+ a b))) #| --> ((lambda a b (+ a b)) 1 2) ; t |#
19:14:44
makomo
elderK: in the end, whether or not a macro argument is evaluated depends on the expansion produced. if the expansion evaluates an expression that was bound to a macro argument ARG, we say that the macro evaluates ARG
19:14:45
pjb
elderK: Sorry, I don't see the difference between 300 characters of english and 300 characters of lisp.
19:15:23
elderK
pjb: It's less the code that is the problem, tbh. It's more than in IRC, it's all squished into one or two lines and I'd need to copy it out, format it, so that I could understand it. The more code there is, the more I need to do that.
19:15:48
makomo
elderK: but saying that "the macro evaluates ARG" is technically incorrect, as it's not the macro that evaluates it (at macroexpansion time), it's the expansion that it produces
19:16:07
makomo
but evaluating at macroexpansion-time is so rare that we take that sentence to mean the conventional thing that everyone just described
19:16:12
pjb
emacs matches the parentheses so you don't have to copy and paste and indent in general. it's enough to move the cursor over the parentheses. emacs shows the structure autoamtically.
19:17:07
elderK
makomo: Thank you. And aye, I should be clearer. White_Flame, that's how I see macros too.
19:17:28
pjb
elderK: but don't you already have a command that does that automatically? I thought vim was scritable too.
19:18:00
elderK
pjb: Vim handles paren matching, etc, etc. But code in IRC still requires me to copy the stuff out of IRC, into Vim, then I have to do whatever to format it.
19:18:04
makomo
elderK: if you want to document that something actually gets evaluated at macroexpansion-time, then you would say "evaluates ARG at macroexpansion-time" (instead of just "evaluates ARG")
19:18:06
pjb
elderK: see for example: com.informatimago.common-lisp.cesarum.utility:define-structure-class
19:19:26
pjb
(defpackage "COM.INFORMATIMAGO.MY.CURRENT.PROGRAM" (:use "COMMON-LISP" "COM.INFORMATIMAGO.COMMON-LISP.CESARUM.UTILITY)) (in-package "COM.INFORMATIMAGO.MY.CURRENT.PROGRAM")
19:20:04
pjb
elderK: Since most of my code is written in libraries, it cannot use package nicknames.
19:22:16
elderK
I kind of want to reimplement binary-types as a learning exercise. I'd like to see if I can do it cleaner.
19:23:03
elderK
Which raises another question: Macro expansion is recursive, right? Like, if a macro's expansion has another macro in it, that macro will be expanded and do on until it's entirely expanded?
19:23:56
jcowan
Specifically, when a form is being macroexpanded, it is examined for the outermost macro(s) and they are expanded and plugged back into the form. This repeats until no more macroexpansion can be done.
19:24:08
elderK
It seems like it might be useful to have helper-macros then. Smaller macros that help implement the larger ones. Maybe that would have helped make define-binary-struct more understandable.
19:25:24
elderK
So, is there anything wrong with using macros as a way to conveniently destructure stuff?
19:28:40
pjb
quicklisp uses it to log the packages that are loaded and display the dots when compiling, I believe.
19:29:04
elderK
binary-types goes through a lot of effort to like, destructure it's input in a lot of ways. Is there anything against defining a macro to do that for you?
19:29:31
elderK
Probably best to write it as a normal function though, right? Maybe local to the macro itself.
19:29:58
pjb
again, macros are functions like other functions, So you can refactorize them as you wish and would do for other functions.
19:30:33
elderK
I guess this does raise an interesting question though, at least for me: How do you ensure that a macro, which has a ton of local functions, is understandable? Do you just ensure they are all small? Is there some conventional way to format it such that things are better... delineated?
19:30:39
pjb
And if you re-read my example substituting backquote with list and other abstract functions I gave yesterday, it more readable.
19:31:10
elderK
I would have broken the expansion process into a lot of little helper functions, that would be available at compile-time.
19:32:41
elderK
It's a lot easier for me to deal with lots of small functions, than one giant overnested one.
19:33:35
elderK
Although, there must be a way to format the code such that a bunch of local functions bound with flet, are jsut as understandable as a bunch of functions made with defun.
19:34:02
elderK
The deeper you are nested when you define your functions, the less space you have per line for the body of a function.
19:34:38
elderK
So, just because things are all in a list, doesn't mean they have to be rammed up together, you can insert whitespace and stuff where you please, if it helps. Cool :)
19:35:14
elderK
equwal: Longer vs Wider? :) I don't own the LoL book yet, I am unfamiliar with those macros.
19:36:12
equwal
I just mean if you want to have locally bound functions without using let-like forms you can use anaphors. https://letoverlambda.com/index.cl/toc
19:37:17
makomo
equwal: yeah, same. i read it already, but i wanted to have a deadtree copy as well :-D
19:38:35
equwal
makomo: I used to have paper copies of a bunch of books, but once I read them I found it is easier to have the HTML files stored locally from httrack.
19:39:05
makomo
say i have a "context macro" (i.e. WITH-SOMETHING) but it doesn't really take any arguments except for the body. should i still have an empty list as its 2nd argument just because of convention or not?
19:39:51
makomo
equwal: i also read all of my books in digital form most of the time, but this one i wanted to have irl :-)
19:40:12
equwal
I like to minimize parentheses even when it breaks convention. Anyone with slime can see the arglist in the minibuffer anyway, why not use it?
19:41:22
equwal
Personally I think COND is a bit of a mistake with the (cond (predicate result)) syntax. (cond predicate result) would have been better I think, for example.
19:42:29
pjb
(cond (condition1 expr11 expr12 … expr1n) (condition2 expr21 expr22 … expr2n) … (conditionp exprp1 exprp2 … exprpn)
19:43:00
pjb
also, there's no difference in memory and processing time between an a-list and a p-list.
19:43:18
elderK
equwal: I find electronic books to be a lot better than deadtree these days, mostly because of the ability to zoom :)
19:43:57
pjb
You can even define a macro (cond. test1 => a b c test2 => d e test3 => f g h else i j)
19:44:22
equwal
Well that is a place where I don't want a print copy. The locally stored hyperspec with slime is the best way to look at code docs I've ever used.
19:46:37
jackdaniel
I'm talking about his personal aesthetics, not yours, so you can't informely say nope (unless you are the same person)
19:47:17
pjb
or (if* condition then something else) if you prefer. or (if* condition else something) for unless
19:48:23
equwal
I think an example that supports my case is where you have a macro that calls another macro for every argument. Like if you have a unit test macro (deftest code result) you might have (deftests code1 result code2 result...) instead of (deftests (code1 result) (code2 result)).
19:52:19
NoNumber
Is PCL still a recommended text here in #lisp? Want to make sure I'm not wasting my time going through it.
19:52:30
pjb
and of course, with embedded ifs: (loop repeat 1 if (= a 1) then if (= b 1) do (something) else do (something-else) end else do (something-a/=1))