SuperObject

What is JSON ?

• JSON (JavaScript Object Notation) is a lightweight data-interchange format.
• It is easy for humans to read and write.
• It is easy for machines to parse and generate.
• It is based on a subset of the JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999.
• JSON is a text format that is completely language independent but uses conventions that are familiar to programmers.
• These properties make JSON an ideal data-interchange language.
• You can get more informations on json.org.

{"name": "Jon Snow",/* this is a comment */"dead": true,"telephones": ["000000000","111111111111"],"age": 33,"size": 1.83,"adresses": [{"adress": "foo","city": "The wall","pc": 57000},{"adress": "foo","city": "Winterfell","pc": 44000}]}

Parsing a JSON data structure

var
obj: ISuperObject;
begin
obj := SO('{"foo": true}');
obj := TSuperObject.ParseString('{"foo": true}');
obj := TSuperObject.ParseStream(stream);
obj := TSuperObject.ParseFile(FileName);
end;

Accessing data

There isn't individual datastructure for each supported data types. They are all an object: the ISuperObject.

 val := obj.AsString;
val := obj.AsInteger;
val := obj.AsBoolean;
val := obj.AsDouble;
val := obj.AsArray;
val := obj.AsObject;
val := obj.AsMethod;

How to read a property value of an object ?

 val := obj.AsObject.S['foo']; // get a string
val := obj.AsObject.I['foo']; // get an Int64
val := obj.AsObject.B['foo']; // get a Boolean
val := obj.AsObject.D['foo']; // get a Double
val := obj.AsObject.O['foo']; // get an Object (default)
val := obj.AsObject.M['foo']; // get a Method
val := obj.AsObject.N['foo']; // get a null object

How to read a value from an array ?

// the advanced way
val := obj.AsArray.S[0]; // get a string
val := obj.AsArray.I[0]; // get an Int64
val := obj.AsArray.B[0]; // get a Boolean
val := obj.AsArray.D[0]; // get a Double
val := obj.AsArray.O[0]; // get an Object (default)
val := obj.AsArray.M[0]; // get a Method
val := obj.AsArray.N[0]; // get a null object

Using paths

Using paths is a very productive method to find an object when you know where is it. This is some usage cases:

 obj['foo']; // get a property
obj['123']; // get an item array
obj['foo.list']; // get a property from an object
obj['foo[123]']; // get an item array from an object
obj['foo(1,2,3)']; // call a method
obj['foo[]'] := value; // add an item array

you also can encapsulate paths:

 obj := so('{"index": 1, "items": ["item 1", "item 2", "item 3"]}');
obj['items[index]'] // return "item 2"

or recreate a new data structure from another:

 obj := so('{"index": 1, "items": ["item 1", "item 2", "item 3"]}');
obj['{"item": items[index], "index": index}'] // return {"item": "item 2", "index": 1}

Browsing data structure

Using Delphi enumerator.

Using Delphi enumerator you can browse item's array or property's object value in the same maner.

var
item: ISuperObject;
beginfor item in obj['items'] do ...

you can also browse the keys and values of an object like this:

var
item: TSuperAvlEntry;
beginfor item in obj.AsObject do ...
begin
item.Name;
item.Value;
end;

Browsing object properties without enumerator

var
item: TSuperObjectIter;
beginif ObjectFindFirst(obj, item) thenrepeat
item.key;
item.val;
untilnot ObjectFindNext(item);
ObjectFindClose(item);

Browsing array items without enumerator

var
item: Integer;
beginfor item := 0to obj.AsArray.Length - 1do
obj.AsArray[item]

RTTI & marshalling in Delphi 2010

type
TData = record
str: string;
int: Integer;
bool: Boolean;
flt: Double;
end;
var
ctx: TSuperRttiContext;
data: TData;
obj: ISuperObject;
begin
ctx := TSuperRttiContext.Create;
try
data := ctx.AsType<TData>(SO('{str: "foo", int: 123, bool: true, flt: 1.23}'));
obj := ctx.AsJson<TData>(data);
finally
ctx.Free;
end;
end;

Saving data

 obj.AsJSon(options);
obj.SaveTo(stream);
obj.SaveTo(filename);

Helpers

 SO(['prop1', true, 'prop2', 123]); // return an object {"prop1": true, "prop2": 123}
SA([true, 123]); // return an array [true, 123]

Non canonical forms

The SuperObject is able to parse non canonical forms.

// unquoted identifiers
SO('{foo: true}');
// unescaped or unquoted strings
SO('{собственность: bla bla bla}');
// excadecimal
SO('{foo: \xFF}');