Re: callback support for encoding JSON

[Marcus Comstedt (ACROSS) (Hail Ilpalazzo!) @ Pike (-) developers forum]

Also, testing on PIKE_T_FUNCTION might not be such a good idea, since
then using an object with a `() operator won't work, neither will
using a program as a callback.  The builtin callablep() recognizes
PIKE_T_FUNCTION, PIKE_T_PROGRAM, PIKE_T_OBJECT, and PIKE_T_ARRAY, but
a better approach might be to just try apply_svalue if the svalue is
nonzero and not a string (the case you want to handle differently).