Hacker Newsnew | past | comments | ask | show | jobs | submit | tromp's commentslogin

> fly two to three times faster (about 460 miles per hour, compared to 90 miles per hour)

Is this AI math? That's over 5 times faster.

reply


> The Simple Rule

> If the Friday you’re referring to is beyond seven days from today, including today, it’s next Friday.

That's not a such simple rule. I'm not even sure what "including today" means.

A simple rule would be: next Friday is the first Friday after today.

The whole existence of this website suggests that the term "Next Friday" is at best ambiguous. Especially on a Saturday or Sunday, many people will interpret "Next Friday" as the Friday of next week. So just be explicit and say "Friday next week".

reply


Your rule is describing this Friday, not next Friday.

reply


Except on Friday's, when "this Friday" means today. On other days, many people indeed use "this" and "next" synonymously.

reply


Perhaps this is regional? I would identify this Friday as the 15th, and next Friday as the 22nd. Next Friday always means the Friday after the next one, which I notice is insane as a matter of logic, but is the local usage I am familiar with.

reply


> Next Friday always means the Friday after the next one

You're using "the next one" i.e. the next Friday, to refer to the first one after today.

reply


Yes, next Friday is not the next Friday, those two phrases are very different despite that being weird.

Not endorsing this, just reporting from usage.

reply


I've become used to saying: "This coming Friday"

reply


One of the smallest implementations is my heavily obfuscated https://www.ioccc.org/2012/tromp/ :

           Int L[A],m,b,*D=A,
            *c,*a=L,C,*U=L,u;s
             (_){u--&&s(a=*a);}
              char*B,I,O;S(){b=b
               --?b:m|read(0,&I,1
                )-1;return~I>>b&1;
                 }k(l,u){for(;l<=u;
                  U-L<A?*U++=46^l++[
                   "-,&,,/.--/,:-,'/"
                   ".-,-,,/.-,*,//..,"
                  ]:exit(5));}p(Int*m){
                 return!*U?*m=S()?U++,!S
                ()?m[1]=p(++U),2:3:1,p(U)
               :S()?U+=2:p(U[1]++),U-m;}x(
              c){k(7*!b,9);*U++=b&&S();c&&x
             (b);}d(Int*l){--l[1]||d(l[d(*l),
            *l=B,B=l,2]);}main(e){for(k(10,33
           ),a[4]-=m=e-2&7,a[23]=p(U),b=0;;e-2
          ?e?e-3?s(D=a),C=a  [3],++1[a=a[2]],d(
         D):c?D=c,c=*D,*D=    a,a=D:exit(L[C+1])
        :C--<23?C=u+m&1?O      =O+O|C&1,9:write(m
       ||(O=C+28),&O,1)+        1:(S(),x(0<b++?k(0,
      6),U[-5]=96:0)):(          D=B?B:calloc(4,X))
     ?B=*D,*D=c,c=D,D[            2]=a,a[++D[1]]++,D
    [3]=++C+u:exit(6)              )e=L[C++],u=L[C];}
while a less obfuscated and highly performant implementation https://github.com/tromp/AIT/blob/master/uni.c based on combinatory graph reduction takes 446 lines.

reply


Even the unobfuscated version is a work of art. You rarely see such concise and honestly beautiful C code.

reply


> Alonzo Church developed the lambda calculus in 1929.

His first publication that showed the elements of the lambda calculus was the 1932 paper "A set of postulates for the foundation of logic", as I cited in my recent paper [1]. It's quite possible he worked on it prior to 1932, but I don't know of any credible evidence on that (would be very interested to learn about any).

> Wait! How the heck is this a "programming" language? > At first glance, this simple language seems to lack both recursion and iteration, not to mention numbers, booleans, conditionals, data structures and all the rest. How can this language possibly be general-purpose?

What most stops lambda calculus from being a programming language is that it doesn't directly support I/O. However, one can adopt some very simple conventions for representing bits, lists of bits (bytes), and lists of bytes, and for letting a lambda term operate on these [2] which make the so-called Binary Lambda Calculus (BLC) a programming language.

And a very expressive language it is too: a BLC self interpreter [4] can be as small as the 170-bits

    01000110100001000
    00001100000010111
    00110000111111100
    00101110011111110
    00000111100000010
    11101110011011110
    01111111100001111
    11110000101111010
    01110100101111101
    00101101010011010

 which encodes the term

    (λ11)(λ(λλλ1(λλ2(1(λ6(λ2(6(λλ3(λλ23(14))))(7(λ7(λ31(21)))))))(41(111))))(11))
in De Bruijn notatation, with lambda diagram [3]

    ┬─┬ ────────────────────────────────────────────┬─┬
    └─┤ ──────┬───────────────┬──────────────────── ├─┘
      │ ──────┼───┬───────────┼─┬─────────┬──────── │
      │ ┬─────┼───┼───────────┼─┼─────────┼──────── │
      │ │ ┬───┼───┼───────────┼─┼─────────┼──────── │
      │ │ ┼─┬─┼───┼───────────┼─┼─────────┼─┬─┬─┬─┬ │
      │ │ │ │ ┼─┬─┼───────────┼─┼──────── └─┤ └─┤ │ │
      │ │ │ │ │ ┼─┼─┬─────────┼─┼─┬──────   │   ├─┘ │
      │ │ │ │ │ │ │ ┼───────┬ │ ┼─┼───┬──   ├───┘   │
      │ │ │ │ │ │ │ ┼───┬───┼ │ │ ┼─┬─┼─┬   │       │
      │ │ │ │ │ │ │ │ ┬─┼───┼ │ │ └─┤ ├─┘   │       │
      │ │ │ │ │ │ │ │ ┼─┼─┬─┼ │ │   ├─┘     │       │
      │ │ │ │ │ │ │ │ └─┤ ├─┘ │ ├───┘       │       │
      │ │ │ │ │ │ │ │   ├─┘   ├─┘           │       │
      │ │ │ │ │ │ │ ├───┘     │             │       │
      │ │ │ │ │ │ ├─┘         │             │       │
      │ │ │ │ │ └─┤           │             │       │
      │ │ │ │ │   ├───────────┘             │       │
      │ │ │ │ ├───┘                         │       │
      │ │ │ ├─┘                             │       │
      │ │ └─┤                               │       │
      │ │   ├───────────────────────────────┘       │
      │ └───┤                                       │
      │     ├───────────────────────────────────────┘
      └─────┘
10 times smaller than the 7 lines of R5RS Scheme

    (define (eval e env) (cond
      ((symbol? e)       (cadr (assq e env)))
      ((eq? (car e) 'λ)  (cons e env))
      (else              (apply (eval (car e) env) (eval (cadr e) env)))))
    (define (apply f x)
      (eval (cddr (car f)) (cons (list (cadr (car f)) x) (cdr f))))
    (display (eval (read) '())) (newline)
> This code will read a program from stdin, parse it, evaluate it and print the result.

Except that it leaves all the actual parsing to the "read" library function.

In contrast, the BLC code does all parsing itself. One of the neatest tricks is how it represents the environment as a list built with

      cons' =  \x\y\zx\zy. zx x (zy y)
which allows a list of bits like "1110" (the code for de Bruijn index 3) to index the environment by simply applying it to the environment.

[1] https://www.mdpi.com/1099-4300/28/5/494 "The Largest Number Representable in 64 Bits"

[2] https://gist.github.com/tromp/86b3184f852f65bfb814e3ab0987d8...

[3] https://tromp.github.io/cl/diagrams.html

[4] https://github.com/tromp/AIT/blob/master/ait/int.lam

reply


The build process: https://www.youtube.com/watch?v=HzI2GgTZAfE

reply


something similar: https://www.npmjs.com/package/best-sugar-daddy-apps

reply


Design of this (not quite) unpickable lock: https://www.youtube.com/watch?v=-qUu8kIliy8

reply


> import Control.Monad (guard)

> "fizz" <$ guard (rem i 3 == 0)

I prefer the more transparent

    if i `mod` 3 == 0 then Just "fizz" else Nothing

reply


By having a small daily dollar value (the column "PoW Produced (24h) in [1]). All but the top 15 coins sorted by that column have less than $10k emitted per day in block rewards, which limits the power that miners can spend on competing for it.

[1] https://www.f2pool.com/coins

reply


That would mean all but the top 15 coins are exploitable for under $10k per day

reply


But the value of a 51% attack is roughly proportional to marketcap, so while they are cheaper to attack, there's less incentive for the attack. The most (relatively) vulnerable coins are those where the daily dollar value is low relative to the market cap.

reply


Correct; both Bitcoin and Monero use Hashcash as PoW, only differing in the choice of hash function. Verification is only different from a solution attempt in asymmetric (i.e. non-Hashcash) PoW, such as Cuckoo Cycle or (the poorly named) Equihash.

reply


A similar Haskell success story (from Bellroy) is the subject of an upcoming Melbourne Compose meeting: https://luma.com/uhdgct1v

reply


Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: