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[Tim B.]

We have a JSON structure similar to the following being returned from a web service:-

{
  "id": "96gOMKS2",
  "count": 10,
  "feasible": true,
  "route": {
    "0": {
      "name": "LOC 1",
      "arrival": 0,
      "distance": 0
    },
    "1": {
      "name": "LOC 2",
      "arrival": 2,
      "distance": 1.2
    },
    "2": {
      "name": "LOC 3",
      "arrival": 4,
      "distance": 2.3
    }
  }
}

How does this translate into an FGL variable?  When I try "CALL util.JSON.parse" I get "JSON parse error: Unexpected '{', target is not a RECORD or DICTIONARY".

The problem, I assume, is the "0", "1", "2", which I'm not sure how to handle or translate.

I've tried the following:-

       m_resp DYNAMIC ARRAY OF RECORD
           id       CHAR(8),
           count    SMALLINT,
           feasable BOOLEAN,
           route DYNAMIC ARRAY OF RECORD
               name VARCHAR(40),
               arrival  DECIMAL(6,1),
               distance DECIMAL(6,1)
           END RECORD
       END RECORD
and
       m_resp DYNAMIC ARRAY OF RECORD
           id       CHAR(8),
           count    SMALLINT,
           feasable BOOLEAN,
           route DYNAMIC ARRAY OF RECORD
               num INT,
               rec RECORD
                   name VARCHAR(40),
                   arrival  DECIMAL(6,1),
                   distance DECIMAL(6,1)
               END RECORD
           END RECORD
       END RECORD
and
       m_resp DYNAMIC ARRAY OF RECORD
           id       CHAR(8),
           count    SMALLINT,
           feasable BOOLEAN,
           route DICTIONARY OF RECORD
                   name VARCHAR(40),
                   arrival  DECIMAL(6,1),
                   distance DECIMAL(6,1)
           END RECORD
       END RECORD


I assume "route" is a DICTIONARY(?), but I'm not sure how to create variable to fit this structure.

Solutions or ideas gratefully received.

Tim

[Rene S.]

Try this:

Code

m_resp RECORD
          id       CHAR(8),
          count    SMALLINT,
          feasable BOOLEAN,
          route DICTIONARY OF RECORD
                  name VARCHAR(40),
                  arrival  DECIMAL(6,1),
                  distance DECIMAL(6,1)
          END RECORD
      END RECORD
 

Rene

[Sebastien F.]

Try this:

Code

IMPORT util
 
DEFINE rec  RECORD
              id STRING,
              count FLOAT,
              feasible BOOLEAN,
              route DICTIONARY OF RECORD
                  name STRING,
                  arrival FLOAT,
                  distance FLOAT
              END RECORD
            END RECORD
 
MAIN
    DEFINE js STRING
    LET js = '{
  "id": "96gOMKS2",
  "count": 10,
  "feasible": true,
  "route": {
    "0": { "name": "LOC 1", "arrival": 0, "distance": 0 },
    "1": { "name": "LOC 2", "arrival": 2, "distance": 1.2 },
    "2": { "name": "LOC 3", "arrival": 4, "distance": 2.3 }
  }
}'
    CALL util.JSON.parse(js, rec)
    DISPLAY util.JSON.format( util.JSON.stringify(rec) )
END MAIN

[Sebastien F.]

Answers have crossed.
Sure using the original types CHAR, VARCHAR, INTEGER, DECIMAL(p,s) is certainly better for your application needs as STRING/FLOAT.
I have got STRING/FLOAT from util.JSON.proposeType()
Seb

[Tim B.]

Thank you both.  I was close, but not quite there.  DICTIONARY is new to me as we're just upgrading to 3.10.

Incidentally, GST 3.00.32 is showing compile errors for the DICTIONARY keyword ("The symbol 'DICTIONARY' does not represent a valid variable type.") but does compile & run OK.  I assume this is because GST is using the original FGL 3.00.10 package it was bundled with, whereas I am actually using FGL 3.10.09 now.  Is there a way to make the inline compiler use the same version of FGL you have in the configuration?

[Sebastien F.]

Why don't you use GST 3.10?
Seb

[Tim B.]

Not quite got round to updating it on this machine.  I should do really though.

[Reuben B.]

Incidentally, GST 3.00.32 is showing compile errors for the DICTIONARY keyword ("The symbol 'DICTIONARY' does not represent a valid variable type.") but does compile & run OK.  I assume this is because GST is using the original FGL 3.00.10 package it was bundled with, whereas I am actually using FGL 3.10.09 now.  Is there a way to make the inline compiler use the same version of FGL you have in the configuration?

... to give you some background,  for real time syntax checking, code completion etc, Studio does not use the same fglcomp as it does for the actual compilation.  If you do a search inside Studio files for fglcomp etc you will find the cut down versions that Studio uses for these code editing purposes.  You will hopefully see a few different versions of this file and can hopefully appreciate why the new 3.1 syntax is not recognised by the 3.0 version of Studio.  You will also face the same issue editing any .xml type files such as .4ad, .4st etc.  Any new tag names, attribute names and values introduced in 3.1 will not be included in the 3.0 definitions and hence will raise false errors in the 3.0 code editor.

With Studio, there should not be anything that holds you back upgrading relatively promptly after each release.  Whilst we can appreciate why sites are still running FGL/GAS/GDC.GRE 3.0, 2.5, 2.4 and worse etc in production, with GST there aren't those same excuses.  By not upgrading promptly, your developers are missing out on the new functionality introduced in Studio in 3.1 http://4js.com/online_documentation/fjs-gst-manual-html/#gst-topics/gst_whatsnew_310.html.  Ideally with GST you have participated and used it during the Early Access Program (EAP) and have the confidence to upgrade to it not long after its general release.

Reuben

[Reuben B.]

This is interesting, with regards the JSON structure, my first instinct upon reading was to use the util.JSON.proposeType method http://4js.com/online_documentation/fjs-fgl-manual-html/#c_fgl_ext_util_JSON_proposeType.html this should propose a sensible solution.   However if I ran that I got the following proposed structure ...

Code

RECORD
    id STRING,
    count FLOAT,
    feasible BOOLEAN,
    route RECORD
        0 RECORD
            name STRING,
            arrival FLOAT,
            distance FLOAT
        END RECORD,
        1 RECORD
            name STRING,
            arrival FLOAT,
            distance FLOAT
        END RECORD,
        2 RECORD
            name STRING,
            arrival FLOAT,
            distance FLOAT
        END RECORD
    END RECORD
END RECORD

... which is not a valid Genero definition, and is not as appropriate as Rene and Seb's suggestion using DICTIONARY.

So question should perhaps be asked, why proposeType did not propose a solution that could be used.  There are two new features introduced in Genero 3.10 that this method was not incorporating.

1. The record names, 0,1,2 are not valid Genero identifiers.  In 3.10 we introduced the json_name to help with the mapping of JSON identifiers to Genero identifiers http://4js.com/online_documentation/fjs-fgl-manual-html/#c_fgl_json_utils_names.html.  Should proposeType have suggested their use?  This is a slight modification on what proposeType proposed, is syntactically valid and "works" with a sample size of 1, but it would most likely not handle real data ...

Code

DEFINE x RECORD
    id STRING,
    count FLOAT,
    feasible BOOLEAN,
    route RECORD
        r0 RECORD ATTRIBUTES (json_name="0")
            name STRING,
            arrival FLOAT,
            distance FLOAT
        END RECORD,
        r1 RECORD ATTRIBUTES (json_name="1")
            name STRING,
            arrival FLOAT,
            distance FLOAT
        END RECORD,
        r2 RECORD ATTRIBUTES(json_name="2")
            name STRING,
            arrival FLOAT,
            distance FLOAT
        END RECORD
    END RECORD
END RECORD

2.  Should proposeType have proposed to use the new DICTIONARY syntax http://4js.com/online_documentation/fjs-fgl-manual-html/#c_fgl_Dictionary_syntax.html that Rene and Seb have suggested in their solutions?  Is it possible for us to simply detect a JSON pattern that matches DICTIONARY and have proposeType suggest it? instead of proposing multiple consecutive records with an identical structure?

Reuben