The FXSL library has a json-document() function (written entirely in
XSLT
2.0 and using the FXSL's LR parsing framework (also written entirely
in XSLT
2.0) ).

When this transformation:

<xsl:stylesheet version="2.0"
 xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
 xmlns:xs="http://www.w3.org/2001/XMLSchema"
 xmlns:f="http://fxsl.sf.net/"
 exclude-result-prefixes="f xs"
 >
 <xsl:import href="../f/func-json-document.xsl"/>

 <xsl:output omit-xml-declaration="yes" indent="yes"/>

 <xsl:variable name="vstrParam" as="xs:string">
{

  "teacher":{
    "name":
      "Mr Borat",
    "age":
      "35",
    "Nationality":
      "Kazakhstan"
             },


  "Class":{
    "Semester":
      "Summer",
    "Room":
      "null",
    "Subject":
      "Politics",
    "Notes":
      "We're happy, you happy?"
           },

  "Students":
  [
    {
      "Smith":
        [{"First_Name":"Mary","sex":"Female"}],
      "Brown":
        [{"First_Name":"John","sex":"Male"}],
      "Jackson":
        [{"First_Name":"Jackie","sex":"Female"}]
    }
  ],


  "Grades":
  [
    {
      "Test":
       [{"grade":"A","points":68},{"grade":"B","points":25},
{"grade":"C","points":15}],
      "Test":
        [{"grade":"C","points":2},{"grade":"B","points":29},
{"grade":"A","points":55}],
      "Test":
        [{"grade":"C","points":2},{"grade":"A","points":72},
{"grade":"A","points":65}]
    }
  ]

}
 </xsl:variable>

 <xsl:template match="/">
    <xsl:sequence select="f:json-document($vstrParam)"/>
 </xsl:template>
</xsl:stylesheet>

is applied (containing essentially your original data, with "First
Name"
changed to "First_Name", and null changed to "null

the following result is produced:

<teacher>
   <name>Mr Borat</name>
   <age>35</age>
   <Nationality>Kazakhstan</Nationality>
</teacher>
<Class>
   <Semester>Summer</Semester>
   <Room>null</Room>
   <Subject>Politics</Subject>
   <Notes>We're happy, you happy?</Notes>
</Class>
<Students>
   <Smith>
      <First_Name>Mary</First_Name>
      <sex>Female</sex>
   </Smith>
   <Brown>
      <First_Name>John</First_Name>
      <sex>Male</sex>
   </Brown>
   <Jackson>
      <First_Name>Jackie</First_Name>
      <sex>Female</sex>
   </Jackson>
</Students>
<Grades>
   <Test>
      <grade>A</grade>
      <points>68</points>
   </Test>
   <Test>
      <grade>B</grade>
      <points>25</points>
   </Test>
   <Test>
      <grade>C</grade>
      <points>15</points>
   </Test>
   <Test>
      <grade>C</grade>
      <points>2</points>
   </Test>
   <Test>
      <grade>B</grade>
      <points>29</points>
   </Test>
   <Test>
      <grade>A</grade>
      <points>55</points>
   </Test>
   <Test>
      <grade>C</grade>
      <points>2</points>
   </Test>
   <Test>
      <grade>A</grade>
      <points>72</points>
   </Test>
   <Test>
      <grade>A</grade>
      <points>65</points>
   </Test>
</Grades>

One can use json-document() in any XPath expressions, for example,
getting
all female students is as easy as:

    f:json-document($vstrParam)/Students/*[sex = 'Female']

and produces:

<Smith>
   <First_Name>Mary</First_Name>
   <sex>Female</sex>
</Smith>
<Jackson>
   <First_Name>Jackie</First_Name>
   <sex>Female</sex>
</Jackson>


I will fix the implementation of json-document() to replace whitespace
in
element names with underscores and to process the unquoted string
null.


Cheers,
Dimitre Novatchev



On Dec 13, 7:52 pm, "Jasper" <notaro...@dontmail.com> wrote:
> Hi, Maybe this is off-topic, but perhaps you can help. I'm looking for ideas
> on how to parse a data file.
>
> I dont know XML but I know it parses data in text format.
>
> I have a structured data file of the general form shown below. I dont have
> any definition of the data. Basically it looks like it is hierarchical,
> token/data pairs defined by brackets and square brackets.
>
> I would like to parse this out into some sort of data object(s) in C++  so
> that I can gain programmatic access to the variables.
>
> My app is C++ so the solution must be the same. Also it must be very
> lightweight and *very* fast as I must decode multiple pages in realtime.
>
> Would adapting an XML parser to do this be a possible solution?
>
> Any pointers/ideas/references/code snippets/observations appreciated.
>
> TIA
>
> Basic example showing data structure (whitespaces and carriage returns added
> by me for clarity).
>
> {
>
> "teacher":{
>   "name":
>     "Mr Borat",
>   "age":
>     "35",
>   "Nationality":
>     "Kazakhstan"},
>
> "Class":{
>   "Semester":
>     "Summer",
>   "Room":
>     null,
>   "Subject":
>     "Politics",
>   "Notes":
>     "We're happy, you happy?"},
>
> "Students":
> [
> {
>   "Smith":
>     [{"First Name":"Mary","sex":"Female"}],
>   "Brown":
>     [{"First Name":"John","sex":"Male"}],
>   "Jackson":
>     [{"First Name":"Jackie","sex":"Female"}]}
>
> ],
>
> "Grades":
> [
> {
>   "Test":
>      [{"grade":"A","points":68},{"grade":"B","points":25},{"grade":"C","points":-15}],
>   "Test":
>     [{"grade":"C","points":2},{"grade":"B","points":29},{"grade":"A","points":5-5}],
>   "Test":
>     [{"grade":"C","points":2},{"grade":"A","points":72},{"grade":"A","points":6-5}]}
>
> ]
>
>
>
> }- Hide quoted text -
>
> - Show quoted text -