Degenerate Conic

JSON

There are a lot a JSON libraries available for Fortran nowadays. The complete list, as far as I know is:

fson Fortran 95 JSON Parser. JSON-Fortran is a fork of this library. (started 2012).
YAJL-Fort A Modern Fortran Interface to YAJL. This one is an interface to a C library, and not pure Fortran. See also petaca. (started 2013).
JSON-Fortran A Fortran 2008 JSON API. This is my library. As far as I know, this was the first production-ready JSON parser written in modern Fortran. (started 2014).
fortjson JSON library written in Fortran 2003. Designed with portability across HPC architectures in mind. (started 2018).
jsonff JSON for Fortran. (started 2019).

Example

Here's an example of using JSON-Fortran to read in some data from a JSON string:

program test

 use json_module, wp => json_RK, ip => json_IK

 implicit none

 type(json_file) :: json
 integer(ip) :: t
 real(wp),dimension(:),allocatable :: x

 call json%deserialize('{"t": 1, "x": [2.0, 3.0, 4.0]}')

 call json%get('t', t); write(*,*) t
 call json%get('x', x); write(*,*) x

end program test

This prints:

           1
   2.00000000000000        3.00000000000000        4.00000000000000

Note that JSON-Fortran has all sorts of options for:

Using different real (real32, real64, and real128) and integer kinds (int8, int16, int32, and int64).
Controlling the JSON format for printing, including number of spaces for indenting, printing vectors on one line only, or full minification with no extra whitespace or line breaks.
Support for comments in a JSON file.
Multiple ways to get data from a JSON structure, such as RFC 6901 "JSON Pointer" paths or JSONPath) "bracket-notation".
Graceful handing of unusual inputs such as NaN or Infinity.
Thread safe error handling.

Degenerate Conic

Algorithms • Modern Fortran Programming • Orbital Mechanics

Jun 13, 2021

JSON

Example

See also