[Nix-dev] isFloat

[Christian Theune]

Hi,

(I lost a mail. Hopefully this doesn’t end up in a double post).

I got it working and made a ticket to get into a more structured working mode. :)

nix-instantiate --eval -E '123.45 * 1E2'
12345

If anyone wants to follow up:
https://github.com/NixOS/nix/issues/760

Happy to do whatever is necessary to wrap this up. :)

Cheers,
Christian

> On 05 Jan 2016, at 00:48, Christian Theune <ct at flyingcircus.io> wrote:
> 
> Hi,
> 
> alright. I was really interested in trying to see whether I can figure out what’s going on.
> 
> I didn’t quite get it working today and my lack of Flex/Bison understanding is blocking me from figuring out what’s going on. :/
> 
> Most changes were done by reviewing everything that touched the integer handling and following all traces of all things it touched.
> 
> My current work is here:
> https://github.com/NixOS/nix/compare/master...ctheune:ctheune-floats?expand=1
> 
> For some reason, the lexer seems to fail picking up the FLOAT symbol _at all_ and complains:
> 
> nix-instantiate --eval -E '123.1'
> error: syntax error, unexpected INT, expecting ID or OR_KW or DOLLAR_CURLY or '"', at (string):1:5
> 
> So it notices the first thing as an INT (I think, it might be a float, but I don’t think so) but the “.” seems to be interpreted as the attribute access operator. I didn’t find the rule for this - can someone point this out to me?
> 
> Overall, I hope I didn’t make too much of a mess. I picked up a few little things along the way that I think warranted a quick correction (NixInt vs. regular int references and using a custom parser instead of stoi - or should that be stol?).
> 
> If someone could help me figure out what I’m butchering in the Lexer (or elsewhere) …
> 
> Cheers,
> Christian
> 
>> On 04 Jan 2016, at 17:27, Eelco Dolstra <eelco.dolstra at logicblox.com> wrote:
>> 
>> Hi,
>> 
>> On 04/01/16 17:12, Rok Garbas wrote:
>> 
>>> should we add this to nixpkgs/lib? it is usefull (using it right now) :)
>> 
>> IMHO, it would be cleaner to add floats to the Nix language. Before somebody
>> decides to implement floating point arithmetic using a bunch of regexps ;-)
>> 
>> --
>> Eelco Dolstra | LogicBlox, Inc. | http://nixos.org/~eelco/
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>> nix-dev mailing list
>> nix-dev at lists.science.uu.nl
>> http://lists.science.uu.nl/mailman/listinfo/nix-dev
> 
> --
> Christian Theune · ct at flyingcircus.io · +49 345 219401 0
> Flying Circus Internet Operations GmbH · http://flyingcircus.io
> Forsterstraße 29 · 06112 Halle (Saale) · Deutschland
> HR Stendal HRB 21169 · Geschäftsführer: Christian. Theune, Christian. Zagrodnick
> 

--
Christian Theune · ct at flyingcircus.io · +49 345 219401 0
Flying Circus Internet Operations GmbH · http://flyingcircus.io
Forsterstraße 29 · 06112 Halle (Saale) · Deutschland
HR Stendal HRB 21169 · Geschäftsführer: Christian. Theune, Christian. Zagrodnick

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