fixing fast float stod conversion according to ST_Number schema specification

[gangatp]

• Allowing leading + sign

• Not allowing , separated values

  • example: for a comma separated value 123,456 . The result from from_chars will be result=123.0 and answer.ptr = ',456'

  auto answer = fast_float::from_chars(input.data(), input.data()+input.size(), result);
  if(answer.ec != std::errc()) {
  // check error
  }
  if(answer.ptr[0] == ',') {
  // unexpected delimiter
  }

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (e77162c) 69.19% compared to head (324ed58) 69.20%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #339   +/-   ##
========================================
  Coverage    69.19%   69.20%           
========================================
  Files          271      271           
  Lines        28688    28691    +3     
========================================
+ Hits         19851    19855    +4     
+ Misses        8837     8836    -1     

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[martinweismann]

good idea to add a test there.

Please explain what the content of the file is and why it should fail.
Also please change the name to something meaningfull.

[martinweismann]

let's also add a test for that, please.

[alexanderoster]

I would prefer that we do never add such style of code. While it is shorter, it is a landmine and who knows on what situation and platform (or little change by somebody) answer.ptr[0] is evaluated when answer.ptr == nullptr.

Making two if statements out of it is much easier to read and much safer.

[gangatp]

if(answer.ptr){
if(answer.ptr[0] == ','){
throw here
}
}

I can make this into two if statements for readability, but that would mean the same. Did you mean anything else?

[alexanderoster]

That's what I meant, yes :)