superobject

Posted 2020-12-28 hnxxcxg

GITHUB：

https://github.com/hgourvest/superobject

# 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](http://www.json.org).

```js
{
"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

```pas
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.

```pas
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 ?

```pas
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 ?

```pas
// 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:

```pas
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:

```pas
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:

```pas
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.

```pas
var
item: ISuperObject;
begin
for item in obj[‘items‘] do ...
```

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

```pas
var
item: TSuperAvlEntry;
begin
for item in obj.AsObject do ...
begin
item.Name;
item.Value;
end;
```

### Browsing object properties without enumerator

```pas
var
item: TSuperObjectIter;
begin
if ObjectFindFirst(obj, item) then
repeat
item.key;
item.val;
until not ObjectFindNext(item);
ObjectFindClose(item);
```

### Browsing array items without enumerator

```pas
var
item: Integer;
begin
for item := 0 to obj.AsArray.Length - 1 do
obj.AsArray[item]
```

## RTTI & marshalling in Delphi 2010

```pas
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

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

## Helpers

```pas
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.

```pas
// unquoted identifiers
SO(‘{foo: true}‘);
// unescaped or unquoted strings
SO(‘{собственность: bla bla bla}‘);
// excadecimal
SO(‘{foo: xFF}‘);
```