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13:56:47
tfb
edgar-rft: setiously, in my most recent job the system was configured by, I think, two (perhaps three) layered m4-style macro languages, each treating the languages below it as strings.
13:59:48
splittist
everyone knows there is no problem in devops that can't be solved by another layer of yaml
14:06:43
tfb
edgar-rft: well, they weren't idiots, anywhere near. I think that the ideas that make Lisp so interesting just are still not widely distributed.
20:49:05
phoe
"eql may not be true of two floats even when they represent the same value. = is used to compare mathematical values."
20:51:27
sjl
1.0d0 and 1.0f0 represent the same value but might not be eql because they're different types (in SBCL)
20:58:27
mfiano
The standard doesn't adopt IEEE754, only recommends its use. They may have been implying that depending on the floating point encoding, it may not hold true, but = does. (eql 0f0 -0f0) ; => NIL, but (= 0f0 -0f0) ; => T
20:58:33
daphnis
how do you write a macro that accepts unquoted symbols and produces a function call with quoted symbols? eg.: (mac a b c) --> (fun 'a 'b 'c)
20:59:11
no-defun-allowed
(defmacro mac (&rest rest) `(fun ,@(loop for symbol in rest collect (list 'quote rest))))
21:03:48
mfiano
alternatively, something like: (defmacro foo (sym &body body) `(,sym ,@(mapcar (lambda (x) `',x) body)))
21:04:29
Nilby
phoe: consider maybe an implementation that natively supported different float formats like maxima's bigfloat
21:05:51
_death
phoe: you can encode all pairs, sans a few large easy-to-demarcate portions of equivalence classes, of floats by bruteforce and try them
21:10:11
mfiano
Always found CLISP's arbitrary precision floats strange, in regard to the constant value pi. IIRC, the manual even says that it is no longer a constant value, which seems wrong to me.
21:12:54
Nilby
_death: Yes, but I'm not that pleased with clisp anymore, and I haven't used sb-mpfr because I worry about implementation in C and possible overhead.
21:17:06
_death
I never found actual use for them.. for floating point, I'm fine with single and double precision.. and sometimes I need to move to a fixed point or maintain my own scaling or use rationals (slow..) or logarithms solve the issue.. but not arbitrary precision floats
21:21:50
Nilby
I love how close to mathematically correct Lisp math is relative to other languages, but it starts getting corrupt with floating point error. I've be gravely injured before (in virtual realites) by floating point error.
21:24:33
_death
Nilby: I love it too, but computation is its own field, and in this field modular arithmetic and floating point have advantages as well