huh, never seen operator "". Seems to be a c++11 feature.
[1] helped me understand it a bit, but Im not sure I see a compelling use case. Does it just provide a shorthand for calling functions on primitive types (and strings) or have I misunderstood? While requiring less characters might it not decrease readability?
The full trie implementation caught my eye, are there no suitable alternatives in std or boost?
Mixed tabs and spaces (?) cause strange display in github in json.h from 555 through 670 or so.
Also at the start of json.h it seems a shame to repeat __builtin_expect rules, how about #if defined() || ?