readme.md

Fortran 95 JSON Parser

Getting Started

program example1

    ! Typical usage should only require an explicit use of the fson module.
    ! The other modules will be used privatley by fson as required.  
    use fson

    ! declare a pointer variable.  Always use a pointer with fson_value.
    type(fson_value), pointer :: value

    ! parse the json file
    value => fson_parse("test1.json")

    ! print the parsed data to the console
    call fson_print(value)    

    ! extract data from the parsed value        

    ! clean up
    call fson_destroy(value)

end program example1

Example JSON

This JSON will serve as a reference for the following examples.
If you are not already familiar with JSON you can read more at: http://www.json.org/ and http://en.wikipedia.org/wiki/JSON.

{
    "name": {
        "first": "George",
        "last": "Crumb"
    },
    "age": 83,
    "website": "www.georgecrumb.net",
    "compositions": [
        {
            "title": "A Little Suite For Christmas, A.D. 1979",
            "instrument": "piano"
        }
    ]
}

Extracting Data

Getting the data from the parsed fson_value to your variable is easy. All extraction is performed through a call to fson_get().
This subroutine is overloaded for different target value types.

! Root fson value.  Remember, always use a pointer with fson value.
type(fson_value), pointer :: value

! The composer's information will be extracted into these variables
character(len=50) :: first,last
integer :: age

! Parse the file.  See the getting started example.

! Extract the name values.  Use the optional path parameter to specify nested values.
call fson_get(value, "name.first", first)
call fson_get(value, "name.last", last)

! Extract the age value. 
call fson_get(value, "age", age)

Extracting Array

Example coming soon. It works in the code, so if you really need it look for the array_callback.

JSON Path

| Operator | Description              | 
|----------|--------------------------|
|    $     | Root object/value        | 
|    @     | The current object/value |
|    .     | Child operator           |
|    []    | Array element            |