json_write_hook/4

Documentation
- Reference manual
- Packages
  - SWI-Prolog HTTP support
    - Supporting JSON
      - library(http/json): Reading and writing JSON serialization
        
        atom_json_term/3
        
        json_read/2
        
        json_read/3
        
        json_write/2
        
        json_write/3
        
        json_write_hook/4
        
        is_json_term/1
        
        is_json_term/2
        
        json_read_dict/2
        
        json_read_dict/3
        
        json_write_dict/2
        
        json_write_dict/3
        
        atom_json_dict/3

Availability::- use_module(library(http/json)).

[semidet,multifile]json_write_hook(+Term, +Stream, +State, +Options)

Hook that can be used to emit a JSON representation for Term to Stream. If the predicate succeeds it must have written a valid JSON data element and if it fails it may not have produced any output. This facility may be used to map arbitrary Prolog terms to JSON. It was added to manage the precision with which floating point numbers are emitted.

Note that this hook is shared by all users of this library. It is generally adviced to map a unique compound term to avoid interference with normal output.

State

and Options are opaque handles to the current output state and settings. Future versions may provide documented access to these terms. Currently it is adviced to ignore these arguments.