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jacobwilliamsjacobwilliams
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preliminary "get by path" routine using the bracket notation.
added some unit tests.
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‎src/json_value_module.F90

Lines changed: 299 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -436,6 +436,7 @@ module json_value_module
436436
procedure,private :: MAYBEWRAP(json_get_alloc_string_vec_by_path)
437437
procedure,private :: json_get_by_path_default
438438
procedure,private :: json_get_by_path_rfc6901
439+
procedure,private :: json_get_by_path_jsonpath_bracket
439440

440441
procedure,public :: print_to_string => json_value_to_string !! Print the [[json_value]]
441442
!! structure to an allocatable
@@ -5530,7 +5531,7 @@ subroutine json_get_by_path(json, me, path, p, found)
55305531
logical(LK),intent(out),optional :: found !! true if it was found
55315532

55325533
character(kind=CK,len=max_integer_str_len),allocatable :: path_mode_str !! string version
5533-
!! of `json%path_mode`
5534+
!! of `json%path_mode`
55345535

55355536
nullify(p)
55365537

@@ -5542,6 +5543,8 @@ subroutine json_get_by_path(json, me, path, p, found)
55425543
call json%json_get_by_path_default(me, path, p, found)
55435544
case(2_IK)
55445545
call json%json_get_by_path_rfc6901(me, path, p, found)
5546+
case(3_IK)
5547+
call json%json_get_by_path_jsonpath_bracket(me, path, p, found)
55455548
case default
55465549
call integer_to_string(json%path_mode,int_fmt,path_mode_str)
55475550
call json%throw_exception('Error in json_get_by_path: Unsupported path_mode: '//&
@@ -5586,13 +5589,12 @@ subroutine json_create_by_path(json,me,path,p,found,was_created)
55865589

55875590
type(json_value),pointer :: tmp
55885591
character(kind=CK,len=max_integer_str_len) :: path_mode_str !! string version
5589-
!! of `json%path_mode`
5592+
!! of `json%path_mode`
55905593

55915594
if (present(p)) nullify(p)
55925595

55935596
if (.not. json%exception_thrown) then
55945597

5595-
! note: path_mode can only be 1 or 2 (which was checked in initialize)
55965598
select case (json%path_mode)
55975599
case(1_IK)
55985600
call json%json_get_by_path_default(me,path,tmp,found,&
@@ -5609,6 +5611,11 @@ subroutine json_create_by_path(json,me,path,p,found,was_created)
56095611
found = .false.
56105612
end if
56115613
if (present(was_created)) was_created = .false.
5614+
!case(3_IK)
5615+
! call json%json_get_by_path_jsonpath_bracket(me,path,tmp,found,&
5616+
! create_it=.true.,&
5617+
! was_created=was_created)
5618+
! if (present(p)) p => tmp
56125619
case default
56135620
call integer_to_string(json%path_mode,int_fmt,path_mode_str)
56145621
call json%throw_exception('Error in json_create_by_path: Unsupported path_mode: '//&
@@ -5658,6 +5665,7 @@ end subroutine wrap_json_create_by_path
56585665
!### Example
56595666
!
56605667
!````fortran
5668+
! type(json_core) :: json
56615669
! type(json_value),pointer :: dat,p
56625670
! logical :: found
56635671
! !...
@@ -5709,17 +5717,17 @@ subroutine json_get_by_path_default(json,me,path,p,found,create_it,was_created)
57095717
!! was actually created. Otherwise
57105718
!! it will be false.
57115719

5712-
integer(IK) :: i !! counter of characters in `path`
5713-
integer(IK) :: length !! significant length of `path`
5714-
integer(IK) :: child_i !! index for getting children
5715-
character(kind=CK,len=1) :: c !! a character in the `path`
5716-
logical(LK) :: array !! flag when searching for array index in `path`
5717-
type(json_value),pointer :: tmp !! temp variables for getting child objects
5718-
logical(LK) :: child_found !! if the child value was found
5719-
logical(LK) :: create !! if the object is to be created
5720-
logical(LK) :: created !! if `create` is true, then this will be
5721-
!! true if the leaf object had to be created
5722-
integer(IK) :: j !! counter of children when creating object
5720+
integer(IK) :: i !! counter of characters in `path`
5721+
integer(IK) :: length !! significant length of `path`
5722+
integer(IK) :: child_i !! index for getting children
5723+
character(kind=CK,len=1) :: c !! a character in the `path`
5724+
logical(LK) :: array !! flag when searching for array index in `path`
5725+
type(json_value),pointer :: tmp !! temp variables for getting child objects
5726+
logical(LK) :: child_found !! if the child value was found
5727+
logical(LK) :: create !! if the object is to be created
5728+
logical(LK) :: created !! if `create` is true, then this will be
5729+
!! true if the leaf object had to be created
5730+
integer(IK) :: j !! counter of children when creating object
57235731

57245732
nullify(p)
57255733

@@ -6190,6 +6198,283 @@ subroutine json_get_by_path_rfc6901(json, me, path, p, found)
61906198
end subroutine json_get_by_path_rfc6901
61916199
!*****************************************************************************************
61926200

6201+
!*****************************************************************************************
6202+
!> author: Jacob Williams
6203+
! date: 9/2/2017
6204+
!
6205+
! Returns the [[json_value]] pointer given the path string,
6206+
! using the "JSON Pointer" path specification defined by the
6207+
! JSONPath "bracket-notation".
6208+
!
6209+
!### Example
6210+
!
6211+
!````fortran
6212+
! type(json_core) :: json
6213+
! type(json_value),pointer :: dat,p
6214+
! logical :: found
6215+
! !...
6216+
! call json%get(dat,"$['store']['book'][1]['title']",p,found)
6217+
!````
6218+
!
6219+
! The first character `$` is optional, and signifies the root
6220+
! of the structure. If it is not present, the the first key is
6221+
! taken to be in the `me` object.
6222+
!
6223+
!### See also
6224+
! * [[json_get_by_path_default]] - subset of JSONPath "dot-notation"
6225+
! * [[json_get_by_path_rfc6901]] - RFC6901 "JSON pointer"
6226+
!
6227+
!### Reference
6228+
! * [JSONPath](http://goessner.net/articles/JsonPath/)
6229+
!
6230+
!@note Uses 1-based array indices (same as [[json_get_by_path_default]],
6231+
! but unlike [[json_get_by_path_rfc6901]] which uses 0-based indices).
6232+
!
6233+
!@warning The `create` logic hasn't been added yet !!!
6234+
6235+
subroutine json_get_by_path_jsonpath_bracket(json,me,path,p,found,create_it,was_created)
6236+
6237+
implicit none
6238+
6239+
class(json_core),intent(inout) :: json
6240+
type(json_value),pointer,intent(in) :: me !! a JSON linked list
6241+
character(kind=CK,len=*),intent(in) :: path !! path to the variable
6242+
!! (using JSONPath
6243+
!! "bracket-notation")
6244+
type(json_value),pointer,intent(out) :: p !! pointer to the variable
6245+
!! specify by `path`
6246+
logical(LK),intent(out),optional :: found !! true if it was found
6247+
logical(LK),intent(in),optional :: create_it !! if a variable is not present
6248+
!! in the path, then it is created.
6249+
!! the leaf node is returned as
6250+
!! a `null` json type and can be
6251+
!! changed by the caller.
6252+
logical(LK),intent(out),optional :: was_created !! if `create_it` is true, this
6253+
!! will be true if the variable
6254+
!! was actually created. Otherwise
6255+
!! it will be false.
6256+
6257+
character(kind=CK,len=:),allocatable :: token !! a token in the path
6258+
!! (between the `['']` or
6259+
!! `[]` characters)
6260+
integer(IK) :: istart !! location of current '['
6261+
!! character in the path
6262+
integer(IK) :: iend !! location of current ']'
6263+
!! character in the path
6264+
integer(IK) :: ival !! integer array index value
6265+
logical(LK) :: status_ok !! error flag
6266+
type(json_value),pointer :: tmp !! temporary variable for
6267+
!! traversing the structure
6268+
integer(IK) :: i !! counter
6269+
integer(IK) :: ilen !! length of `path` string
6270+
logical(LK) :: create !! if the object is to be created
6271+
logical(LK) :: created !! if `create` is true, then this will be
6272+
!! true if the leaf object had to be created
6273+
integer(IK) :: j !! counter of children when creating object
6274+
6275+
!TODO instead of reallocating `token` all the time, just
6276+
! allocate a big size and keep track of the length,
6277+
! then just reallocate only if necessary.
6278+
! [would probably be inefficient if there was a very large token,
6279+
! and then a bunch of small ones... but for similarly-sized ones
6280+
! it should be way more efficient since it would avoid most
6281+
! reallocations.]
6282+
6283+
nullify(p)
6284+
6285+
if (.not. json%exception_thrown) then
6286+
6287+
if (present(create_it)) then
6288+
create = create_it
6289+
else
6290+
create = .false.
6291+
end if
6292+
6293+
p => me ! initialize
6294+
created = .false.
6295+
6296+
if (path==CK_'') then
6297+
call json%throw_exception('Error in json_get_by_path_jsonpath_bracket: '//&
6298+
'invalid path specification: '//trim(path))
6299+
else
6300+
6301+
if (path(1:1)==root .or. path(1:1)==start_array) then ! the first character must be
6302+
! a `$` (root) or a `[`
6303+
! (element of `me`)
6304+
6305+
if (path(1:1)==root) then
6306+
! go to the root
6307+
do while (associated (p%parent))
6308+
p => p%parent
6309+
end do
6310+
end if
6311+
6312+
!keep trailing space or not:
6313+
if (json%trailing_spaces_significant) then
6314+
ilen = len(path)
6315+
else
6316+
ilen = len_trim(path)
6317+
end if
6318+
6319+
if (ilen>1) then
6320+
6321+
istart = 2 ! initialize first '[' location index
6322+
6323+
do
6324+
6325+
if (istart>ilen) exit ! finished
6326+
6327+
! must be the next start bracket:
6328+
if (path(istart:istart) /= start_array) then
6329+
call json%throw_exception(&
6330+
'Error in json_get_by_path_jsonpath_bracket: '//&
6331+
'expecting "[", found: "'//trim(path(istart:istart))//&
6332+
'" in path: '//trim(path))
6333+
exit
6334+
end if
6335+
6336+
! get the next token by checking:
6337+
!
6338+
! * is the token after istart a quote?
6339+
! if so, then search for the next `']`
6340+
! ['']
6341+
!
6342+
! * if not, then maybe it is a number,
6343+
! so search for the next `]`
6344+
! [1]
6345+
!
6346+
! istart iend
6347+
! | |
6348+
! [abcdefg][h][ijk]
6349+
6350+
! verify length of remaining string
6351+
if (istart+2<=ilen) then
6352+
if (path(istart+1:istart+1) == single_quote) then ! ['
6353+
istart = istart + 1 ! move to ' index
6354+
! it should be a key value
6355+
iend = istart + index(path(istart+1:ilen),&
6356+
single_quote//end_array) ! ']
6357+
if (iend>istart) then
6358+
if (iend>istart+1) then
6359+
token = path(istart+1:iend-1)
6360+
else
6361+
token = CK_'' ! blank string
6362+
end if
6363+
! remove trailing spaces in
6364+
! the token here if necessary:
6365+
if (.not. json%trailing_spaces_significant) &
6366+
token = trim(token)
6367+
! have a token, see if it is valid:
6368+
call json%get_child(p,token,tmp,status_ok)
6369+
if (status_ok) then
6370+
! it was found
6371+
p => tmp
6372+
else
6373+
call json%throw_exception(&
6374+
'Error in json_get_by_path_jsonpath_bracket: '//&
6375+
'invalid token found: "'//token//&
6376+
'" in path: '//trim(path))
6377+
exit
6378+
end if
6379+
iend = iend + 1 ! move to ]
6380+
else
6381+
call json%throw_exception(&
6382+
'Error in json_get_by_path_jsonpath_bracket: '//&
6383+
'invalid path: '//trim(path))
6384+
exit
6385+
end if
6386+
else
6387+
! it might be an integer value
6388+
iend = istart + index(path(istart+1:ilen),end_array) ! ]
6389+
if (iend>istart+1) then
6390+
6391+
! this should be an integer:
6392+
token = path(istart+1:iend-1)
6393+
6394+
! verify that there are no spaces or other
6395+
! characters in the string:
6396+
do i=1,len(token)
6397+
! It must only contain (0..9) characters
6398+
! (it must be unsigned)
6399+
if (scan(token(i:i),CK_'0123456789')<1) then
6400+
status_ok = .false.
6401+
exit
6402+
end if
6403+
end do
6404+
if (status_ok) then
6405+
call string_to_integer(token,ival,status_ok)
6406+
if (status_ok) status_ok = ival>0 ! assuming 1-based array indices
6407+
end if
6408+
if (status_ok) then
6409+
! have a valid integer to use as an index, so
6410+
! see if this element is really there:
6411+
call json%get_child(p,ival,tmp,status_ok)
6412+
if (status_ok) then
6413+
! found it
6414+
p => tmp
6415+
else
6416+
! not found
6417+
call json%throw_exception(&
6418+
'Error in json_get_by_path_jsonpath_bracket: '//&
6419+
'invalid array index found: "'//token//&
6420+
'" in path: '//trim(path))
6421+
exit
6422+
end if
6423+
else
6424+
call json%throw_exception(&
6425+
'Error in json_get_by_path_jsonpath_bracket: '//&
6426+
'invalid token: "'//token//&
6427+
'" in path: '//trim(path))
6428+
exit
6429+
end if
6430+
6431+
else
6432+
call json%throw_exception(&
6433+
'Error in json_get_by_path_jsonpath_bracket: '//&
6434+
'invalid path: '//trim(path))
6435+
exit
6436+
end if
6437+
end if
6438+
else
6439+
call json%throw_exception(&
6440+
'Error in json_get_by_path_jsonpath_bracket: '//&
6441+
'invalid path: '//trim(path))
6442+
exit
6443+
end if
6444+
6445+
! set up for next token:
6446+
istart = iend + 1
6447+
6448+
end do
6449+
6450+
end if
6451+
6452+
else
6453+
call json%throw_exception(&
6454+
'Error in json_get_by_path_jsonpath_bracket: '//&
6455+
'expecting "'//root//'", found: "'//path(1:1)//&
6456+
'" in path: '//trim(path))
6457+
end if
6458+
6459+
end if
6460+
6461+
if (json%exception_thrown) then
6462+
nullify(p)
6463+
if (present(found)) then
6464+
found = .false.
6465+
call json%clear_exceptions()
6466+
end if
6467+
else
6468+
if (present(found)) found = .true.
6469+
end if
6470+
6471+
else
6472+
if (present(found)) found = .false.
6473+
end if
6474+
6475+
end subroutine json_get_by_path_jsonpath_bracket
6476+
!*****************************************************************************************
6477+
61936478
!*****************************************************************************************
61946479
!>
61956480
! Alternate version of [[json_get_by_path]] where "path" is kind=CDK.

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