change unit_to_g() to unit_to_default_unit() ?

[hangy]

openfoodfacts-server/lib/ProductOpener/Food.pm

Line 186 in 501837d

$unit eq 'kcal' and return int($value * 4.184 + 0.5);

openfoodfacts-server/lib/ProductOpener/Food.pm

Line 217 in 501837d

$unit eq 'kcal' and return int($value / 4.184 + 0.5);

Apparently, 1 cal = 4.184 J, but why would it make sense to calculate unit_to_g(1, 'kcal') to 4.684 g? Wouldn't this need to use 9 g for fat and 4 g for protein and carbohydrates?

[stephanegigandet]

The function should be named unit_to_default_unit, which is g for pretty much everything, except energy where it's J.

[teolemon]

Renaming to make it clearer