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  3. August 2017

Re: Parsing JSON data into a data structure without knowing variable's names

Jon, thank you for your articles as they give me some hints for this and
other issues. Building a code generator is definitely a good option and I
will go on with it in case no other solutions are possibles.

Henrik, I don't know which language jsonToField function belongs to, but
yes it seems it fulfill my goal as long as even function's parameter can be
a variable and myvar is a variable containing the name or the pointer to a
data structure field.



2017-08-12 17:26 GMT+02:00 Henrik Rützou <hr@xxxxxxxxxxxx>:

Something like this?

myvar = jsonToField('jsonvar1');

On Sat, Aug 12, 2017 at 5:19 PM, Maria Lucia Stoppa <mlstoppa@xxxxxxxxx>
wrote:

Yes, as I said we are already and successfully using YAJL in many
programs
which deal with every single JSON object naming it explicitly.

What I am trying to do is to generalize the process making a routine
which
has a data structure and a JSON as input and can couple every JSON pair
assigning the value to the corresponding variable in the data structure.


2017-08-12 17:10 GMT+02:00 Jon Paris <jon.paris@xxxxxxxxxxxxxx>:

I'm pretty sure that YAJL was what she was talking about n the original
post Henrik.


Jon Paris

www.partner400.com
www.SystemiDeveloper.com

On Aug 12, 2017, at 10:38 AM, Henrik Rützou <hr@xxxxxxxxxxxx> wrote:

Hi Maria,

You should take at look at YAJL that is a C service program that
reads/writes JSON.

Scott Klement has made a RPG-wrapper around it
http://www.scottklement.com/yajl/

More on reading JSON in RPG:

https://www.nicklitten.com/rpg-example-reading-json-using-yajl-ifs/




On Sat, Aug 12, 2017 at 4:07 PM, Maria Lucia Stoppa <
mlstoppa@xxxxxxxxx>
wrote:

Henrik,
I know your points are true and that's how we have done so far, but
I
am
trying to figure out a general routine to be copied in many
different
programs so variable's name can't be hard coded.
Furthermore, JSON structure doesn't necessary reflects data
structure
fields order, only names and types in order to be valued when a
variable
with the same name and of the same type is present.


2017-08-12 15:45 GMT+02:00 Henrik Rützou <hr@xxxxxxxxxxxx>:

It is generally a very bad idea to map JSON to a datastructure (or
anything) without using
the variable name's since the whole idea in JSON is that you may
include
or
exclude
variables and beside that present them in a random sequence.

On Sat, Aug 12, 2017 at 9:12 AM, Maria Lucia Stoppa <
mlstoppa@xxxxxxxxx>
wrote:

Hello,

I am new to this forum, but I have done some research related to
JSON
and
couldn't find anything similar to my issue.

I am working on a proof of concept to code new programs in order
to
parse
the only received parameter formed as a JSON object into a data
structure.

I explain it better: previously, all our programs received a
single
parameter defined as an external data structure, so as soon as
*entry
plist
operation code is executed the data structure and all the fields
in
it
were
filled in and made available for programs to use them (quite
common
solution). External data structure are defined as PF without
member
and
can
be used by any program that need to call the one which received it
as
a
parameter to perform a specific function.

Now we are moving our ERP's graphic interface to web: it means
that
a
program call can be executed by a store procedure called either by
web
applications or by RPG programs. To serve the purpose of having a
quick
UI
response, parameters are passed coded in a JSON object and new
programs
have been coded to parse JSON input parameter field by field using
SK's
JSON APIs (thanks!).

I am guessing whether I can expand and generalize this behavior by
coding a
general routine which takes an external definition of JSON (even
nested)
structure and assigns each object's name found into JSON parameter
to
its
corresponding variable name's value.

My nightmares are: firstly, today's external DS are one level only
and
I
can't figure out how to represent nested levels; secondly how to
dynamically associate the value of JSON pair to its corresponding
variable's value according to its type.

One general idea might be to code some external D specifications
to
be
used
through /COPY option, which represent JSON structure in terms of
qualified
names and types, array included. Then JSON objects can be read
element
by
element but how can I address the right DS variable without
explicitly
write its name?

Can you suggest me some technique I haven't explored yet or any
other
way
to approach the problem?

Thank you


--

Maria Lucia Stoppa
mlstoppa@xxxxxxxxx
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--
Regards,
Henrik Rützou

http://powerEXT.com <http://powerext.com/>
--
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--

Maria Lucia Stoppa
mlstoppa@xxxxxxxxx
--
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(RPG400-L)
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--
Regards,
Henrik Rützou

http://powerEXT.com <http://powerext.com/>
--
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(RPG400-L)
mailing list
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--

Maria Lucia Stoppa
mlstoppa@xxxxxxxxx
--
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mailing list
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--
Regards,
Henrik Rützou

http://powerEXT.com <http://powerext.com/>
--
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