Implementing a bignum calculator – Rob Pike [video]

Re:Implementing a bignum calculator – Rob Pike [video] by willvarfar on Friday December 19, 2014 @04:50AM (#8771623)

He wants to compute some bignums, so he writes an APL interpreter in Go...

Now he is scratching his itch and making nice slides to boot.

However, it would have been simpler for him to have typed "python" at the commandline... Python ints are arb precision :)

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Re:Implementing a bignum calculator – Rob Pike [video] by tptacek on Friday December 19, 2014 @11:19AM (#8772851)

The premise of this comment being that it hadn't occurred to Rob Pike that there were already arbitrary-precision calculators.

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Re:Implementing a bignum calculator – Rob Pike [video] by arthurbrown on Friday December 19, 2014 @06:04AM (#8771776)

Arbitrary precision is handled by https://golang.org/pkg/math/big/

He isn't implementing a bignum package, this is all about the APL interpreter.

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Re:Implementing a bignum calculator – Rob Pike [video] by lispm on Friday December 19, 2014 @06:36AM (#8771844)

or GNU CLISP which not only has big ints, big ratios, big complex (like all Common Lisp implementations), but also big floats.

Big ratios:

    [2]> (/ 5723475972349572938475982734985723984759823749587 7239457928374598723984759237459723497598234)
    5723475972349572938475982734985723984759823749587/7239457928374598723984759237459723497598234

Big complex numbers:

    [4]> (* 572934759237495723482374957239475982374957239847523485 (sqrt -1))
    #C(0 572934759237495723482374957239475982374957239847523485)

Big float numbers:

    [8]> (SETF (EXT:LONG-FLOAT-DIGITS) 1000)
    1000
    [9]> (sqrt 2.0l0)
    1.4142135623730950488016887242096980785696718753769480731766797379907324784621070388503875343276415727350138462309122970249248360558507372126441214970999358314132226659275055927557999505011527820605714701095599716059702745345968620147285174186408891986095523292304843087143214508397626036279952514079896872534L0

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Re:Implementing a bignum calculator – Rob Pike [video] by angersock on Friday December 19, 2014 @11:32AM (#8772930)

Ah yes, but a small userbase!

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Re:Implementing a bignum calculator – Rob Pike [video] by pkhagah on Friday December 19, 2014 @11:52AM (#8773028)

If you're talking about userbase, I presume, Go should have less of a userbase than lisp.

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Re:Implementing a bignum calculator – Rob Pike [video] by deeviant on Friday December 19, 2014 @01:24PM (#8773578)

People use lisp for something other than a programming discussion talking point?

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Re:Implementing a bignum calculator – Rob Pike [video] by reportingsjr on Friday December 19, 2014 @01:43PM (#8773716)

The message board that you posted this to. Written in Arc which is a dialect of lisp.

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Re:Implementing a bignum calculator – Rob Pike [video] by deeviant on Friday December 19, 2014 @04:30PM (#8774644)

Once again, downvotes are leaned on in lieu of wit.

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Re:Implementing a bignum calculator – Rob Pike [video] by deeviant on Friday December 19, 2014 @03:44PM (#8774401)

So you mean they use it to create an application that allows them to... talk about lisp.

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Re:Implementing a bignum calculator – Rob Pike [video] by angersock on Saturday December 20, 2014 @04:27PM (#8777992)

So, the correct answer here would've been that Viaweb--Graham's company that later became Yahoo! Store--was done in Common Lisp. I'm not really aware of any other example of Common Lisp in a real commercial setting other than Mirai (which I think is dead nowadays anyway).

Graham later made Arc, the language in which HN is written. To the best of my knowledge Arc's only major project is in fact Hacker News.

So, essentially, yes, you're correct.

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Re:Implementing a bignum calculator – Rob Pike [video] by lispm on Saturday December 20, 2014 @05:30PM (#8778178)

http://www.ptc.com/product/creo/elements

largely written in a few million lines of Lisp...

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Re:Implementing a bignum calculator – Rob Pike [video] by dsymonds on Friday December 19, 2014 @06:31AM (#8771833)

Yes, but he wasn't trying to compute numbers. He was trying to build a calculator. There's a difference.

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Re:Implementing a bignum calculator – Rob Pike [video] by zaphar on Friday December 19, 2014 @04:27PM (#8774632)

You misattribute the motivation. He wants to play.

Implementing a BigNum calculator using APL concepts is one way to play. I do this all the time. I'll implement something that will never be in production somewhere or useful to anybody purely for the learning experience and challenge of it.

[EDIT: spelling]

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Re:Implementing a bignum calculator – Rob Pike [video] by pjmlp on Friday December 19, 2014 @05:54AM (#8771760)

Lisp would be even better, as he would get the speed of compiled language.

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Re:Implementing a bignum calculator – Rob Pike [video] by mseepgood on Friday December 19, 2014 @01:28PM (#8773615)

In the video he says that he already implemented an APL interpreter in Lisp.

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Re:Implementing a bignum calculator – Rob Pike [video] by raverbashing on Friday December 19, 2014 @05:04AM (#8771656)

> Python ints are arb precision

Python 2 longs or Python 3 ints ;)

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Re:Implementing a bignum calculator – Rob Pike [video] by willvarfar on Friday December 19, 2014 @05:30AM (#8771706)

Automatic promotion from a 32-bit or 64-bit storage to arbitrary precision.

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