The Appveyor test failure is due to a problem with the continuous integration system itself (as noted in other pull requests), and not to the changes in my pull request. The tests do pass on my machine.

I don't really have an opinion for or against this pull request, but note that, as with your other pull request, this can be done from jq itself:

echo '{"test" : "1,000"}' | jq 'with_entries(.value |= (sub(","; "") | tonumber))'

Hi! I think it is is interesting. I'm not sure what's the best thing to do here. As @slapresta says, this can be done in jq code. In general I'd rather jq-code things than C-code them, but here it could be a performance issue. Also, if we're going to allow commas as thousands separators, how much should we care about properly formatted numbers? E.g., is 10,00 acceptable? How about 1,0, or 1,,0,0? What if someone expects 1,05 to be 1.05 (i.e., they expect internationalized number parsing)?

@nicowilliams You raise valid questions. My immediate goal was to fix the problem for my immediate purposes. I'll see if I can find some time to come up with a more general solution.

@slapresta Thanks for the jq version. As @nicowilliams noted there is a performance issue. Also, your solution would have to be adapted to deal with mixed input types (which would further increase complexity). For example,

echo '{"test" : "1,000", "test2" : 1000}' | jq 'with_entries(.value |= (sub(","; "") | tonumber))'
jq: error (at <stdin>:1): number (1000) cannot be matched, as it is not a string

In my opinion, the existing tonumber should be left as-is, partly for stability, but mainly because the existing definition matches the JSON concept of "number" exactly. Anything else it seems would run into internationalization issues.

As far as Anglo-American commas are concerned, it seems to me that it is somewhat arbitrary to remove just one of the commas. Removing commas that are in the wrong position has its disadvantages, but a reasonable generalization of tonumber would be as follows:

def to_n: if type == "string" then gsub(",";"") else . end | tonumber;