Negative numbers in JSON turn to zero in from_json()

[totalgee]

• Compiler Used: Xcode 8.2.1 (clang-800.0.42.1)
• Operating System: OS X 10.11.6
• Architecture (ARM/x86/32bit/64bit/etc): 64bit
• ChaiScript commit: b7e8897 (Dec 29, 2016)

When parsing a JSON file with negative numbers in it (floating point or integer), the negative numbers are converted to zeros.

Minimal Example to Reproduce Behavior

    auto negativeJson = "{ \"x\" : -8, \"y\" : -15, \"z\" : 2 }";
    auto negativeJsonFloat = to_json(["x": -0.08, "y": -15.1, "z": 1.73]);
    print("from_json(${negativeJson}) gives ${from_json(negativeJson)}");
    print("from_json(${negativeJsonFloat}) gives ${from_json(negativeJsonFloat)}");

The above example results in the following output:

from_json({ "x" : -8, "y" : -15, "z" : 2 }) gives [<x, 0>, <y, 0>, <z, 2>]
from_json({
  "x" : -0.080000,
  "y" : -15.100000,
  "z" : 1.730000
}) gives [<x, 0>, <y, 0>, <z, 1.73>]

[totalgee]

Okay, I've got a fix for this, I'll submit a PR soon...

[totalgee]

I'm going to submit another PR, you can choose which of the two solutions you prefer! (-; Probably you'll go for the smaller change, isolated just to JSON code, I'd guess -- unless you think the regular parse_num should handle negatives (obviously, except for this JSON case, it doesn't need to right now)...

[totalgee]

Okay, I've closed #335, as it's probably best to keep this fix local to JSON parsing code. Better to use the fix in #336.

[lefticus]

You are correct that chaiscript's number parser has to be different because of that unary - issue we discussed before. Or at least, it can be different, the parser should consume the - first. I agree at some point we need to merge these fixes, when I last looked at it there was subtle differences with C++ style numbers and JSON style.

[lefticus]

I merged #336, closing this