[Nix-dev] isFloat

[Christian Theune]

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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