test_1 Subroutine

    subroutine test_1(error_cnt)

    !! Read a sample JSON file and retrieve some data from it

    implicit none

    type(json_file) :: json       !! the JSON structure read from the file
    type(json_value),pointer :: p !! a pointer for low-level manipulations
    type(json_core) :: core       !! factory for manipulating `json_value` pointers
    integer,intent(out) :: error_cnt
    integer :: ival
    character(kind=json_CK,len=:),allocatable :: cval
    real(wp) :: rval
    logical :: found

    error_cnt = 0
    call json%initialize()
    if (json%failed()) then
      call json%print_error_message(error_unit)
      error_cnt = error_cnt + 1
    end if

    write(error_unit,'(A)') ''
    write(error_unit,'(A)') '================================='
    write(error_unit,'(A)') '   TEST 1'
    write(error_unit,'(A)') '================================='
    write(error_unit,'(A)') ''

    ! parse the json file:
    write(error_unit,'(A)') ''
    write(error_unit,'(A)') 'parsing file '//dir//filename1

    call json%load_file(filename = dir//filename1)

    if (json%failed()) then    !if there was an error reading the file

      call json%print_error_message(error_unit)
      error_cnt = error_cnt + 1

    else

      ! print the parsed data to the console
      write(error_unit,'(A)') ''
      write(error_unit,'(A)') 'printing the file...'
      call json%print_file()
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      end if

      ! -------------------------
      ! print each variable:

      call core%initialize()
      call json%get(p) ! get root

      namelist_style = .true.
      write(error_unit,'(A)') ''
      write(error_unit,'(A)') 'printing each variable [namelist style]'
      write(error_unit,'(A)') ''
      call core%initialize(unescape_strings=.false.)
      call core%traverse(p,print_json_variable)

      namelist_style = .false.
      write(error_unit,'(A)') ''
      write(error_unit,'(A)') 'printing each variable [JSON style]'
      write(error_unit,'(A)') ''
      call core%initialize(unescape_strings=.true.)
      call core%traverse(p,print_json_variable)

      ! -------------------------

      ! extract data from the parsed value
      write(error_unit,'(A)') ''
      write(error_unit,'(A)') 'get some data from the file...'

      write(error_unit,'(A)') ''
      call json%get('version.svn', ival)
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A,I5)') 'version.svn = ',ival
      end if

      write(error_unit,'(A)') ''
      call json%get('data(1).array(2)', cval)
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A)') 'data(1).array(2) = '//trim(cval)
      end if

      write(error_unit,'(A)') ''
      call json%get('files(1)', cval)
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A)') 'files(1) = '//trim(cval)
      end if

      write(error_unit,'(A)') ''
      call json%get('files(2)', cval)
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A)') 'files(2) = '//trim(cval)
      end if

      write(error_unit,'(A)') ''
      call json%get('files(3)', cval)
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A)') 'files(3) = '//trim(cval)
      end if

      write(error_unit,'(A)') ''
      call json%get('data(2).real', rval)
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A,E30.16)') 'data(2).real = ',rval
      end if

      write(error_unit,'(A)') ''
      call json%get('files[4]', cval)      !has hex characters
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A)') 'files[4] = '//trim(cval)
      end if

      write(error_unit,'(A)') ''
      call json%get('files[5]', cval)      !string with spaces and no escape characters
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      else
        write(error_unit,'(A)') 'files[5] = '//trim(cval)
      end if

      !
      ! Test of values that aren't there:
      ! Note: when using the "found" output, the exceptions are cleared automatically.
      !

      write(error_unit,'(A)') ''
      call json%get('files[10]', cval, found)      !value that isn't there
      if (.not. found) then
        write(error_unit,'(A)') 'files[10] not in file.'
      else
        write(error_unit,'(1x,A)') 'files[10] = '//trim(cval)
        error_cnt = error_cnt + 1
      end if

      write(error_unit,'(A)') ''
      call json%get('version.blah', ival, found)      !value that isn't there
      if (.not. found) then
        write(error_unit,'(A)') 'version.blah not in file.'
      else
        write(error_unit,'(A)') 'version.blah = ',ival
        error_cnt = error_cnt + 1
      end if

      write(error_unit,'(A)') ''
      write(error_unit,'(A)') ' Test removing data from the json structure:'

      call json%get('files', p)         !in the middle of a list
      if (json%failed()) then
          call json%print_error_message(error_unit)
          error_cnt = error_cnt + 1
      else
          call core%initialize()
          call core%remove(p)
          if (core%failed()) then
            call core%print_error_message(error_unit)
            error_cnt = error_cnt + 1
          end if
      end if

      call json%get('data(1).array', p)   !at the end of a list
      if (json%failed()) then
          call json%print_error_message(error_unit)
          error_cnt = error_cnt + 1
      else
          call core%initialize()
          call core%remove(p)
          if (core%failed()) then
            call core%print_error_message(error_unit)
            error_cnt = error_cnt + 1
          end if
      end if

      call json%get('data(2).number', p)  !at the beginning of a list
      if (json%failed()) then
          call json%print_error_message(error_unit)
          error_cnt = error_cnt + 1
      else
          call core%initialize()
          call core%remove(p)
          if (core%failed()) then
            call core%print_error_message(error_unit)
            error_cnt = error_cnt + 1
          end if
      end if

      write(error_unit,'(A)') ''
      write(error_unit,'(A)') 'printing the modified structure...'
      call json%print_file()
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      end if

      write(error_unit,'(A)') ''
      write(error_unit,'(A)') ' Test replacing data from the json structure:'

      call json%get('data(1)', p)
      if (json%failed()) then
          call json%print_error_message(error_unit)
          error_cnt = error_cnt + 1
      else
          call core%initialize()
          call core%update(p,'name','Cuthbert',found)
          if (core%failed()) then
            call core%print_error_message(error_unit)
            error_cnt = error_cnt + 1
          end if
      end if

      !call json%get('data(2)', p)
      !call json%update(p,'real',[1.0_wp, 2.0_wp, 3.0_wp],found)   !don't have one like this yet...

      !use the json_file procedure to update a variable:
      call json%update('version.svn',999,found)
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      end if

      write(error_unit,'(A)') ''
      write(error_unit,'(A)') 'printing the modified structure...'
      call json%print_file()
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      end if

      write(error_unit,'(A)') ''
      write(error_unit,'(A)') 'printing the modified structure (compact mode)...'
      call json%initialize(no_whitespace=.true.)
      call json%print_file()
      if (json%failed()) then
        call json%print_error_message(error_unit)
        error_cnt = error_cnt + 1
      end if

    end if

    ! clean up
    write(error_unit,'(A)') ''
    write(error_unit,'(A)') 'destroy...'
    call json%destroy()
    if (json%failed()) then
      call json%print_error_message(error_unit)
      error_cnt = error_cnt + 1
    end if

    end subroutine test_1