* Some minimal documentation

git-svn-id: trunk@15978 -

.gitattributes

@@ -2014,6 +2014,7 @@ packages/fcl-json/examples/parsedemo.pp svneol=native#text/plain
 packages/fcl-json/examples/simpledemo.lpi svneol=native#text/plain
 packages/fcl-json/examples/simpledemo.pp svneol=native#text/plain
 packages/fcl-json/fpmake.pp svneol=native#text/plain
+packages/fcl-json/src/README.txt svneol=native#text/plain
 packages/fcl-json/src/fpjson.pp svneol=native#text/plain
 packages/fcl-json/src/jsonconf.pp svneol=native#text/plain
 packages/fcl-json/src/jsonparser.pp svneol=native#text/plain

packages/fcl-json/src/README.txt

@@ -0,0 +1,163 @@
+This package implements JSON support for FPC.
+
+JSON support consists of 3 parts:
+
+unit fpJSON contains the data representation. Basically, it defines a set of
+classes:
+
+TJSONData
++- TJSONNumber
+   +- TJSONIntegerNumber
+   +- TJSONFloatNumber
+   +- TJSONInt64Number
++- TJSONString
++- TJSONBoolean
++- TJSONNull
++- TJSONObject
++- TJSONArray
+
+The TJSONData.JSONType property is an enumerated:
+TJSONtype = (jtUnknown, jtNumber, jtString, jtBoolean, jtNull, jtArray, jtObject);
+
+Which allows to determine the type of a value.
+
+The following methods exist:
+
+Procedure Clear;
+  Clears the value. For arrays and objects, removes all elements/members
+Function Clone : TJSONData;
+  Creates an exact replica of the valye
+property Count: Integer;
+  For simple values this is zero, for complex values this is the number of
+  elements/members. Read only.
+property Items[Index: Integer]: TJSONData
+  For simple values, reading this will result in an error. For complex
+  values, this gives access to the members.
+property Value: variant;
+  The value as a variant. Only for simple values.
+Property AsString : TJSONStringType:
+   The value as a string. Only for simple values.
+Property AsFloat : TJSONFloat;
+  The value as a float (double). only for simple values.
+Property AsInteger : Integer ;
+  The value as an integer. only for simple values.
+Property AsInt64 : Int64;
+  The value as an 64-bit integer. only for simple values.
+Property AsBoolean : Boolean ;
+  The value as a boolean.
+Property IsNull : Boolean ;
+  Is the value Null ?
+Property AsJSON : TJSONStringType 
+  Return the value in JSON notation. For simple and complex values.
+
+The TJSONArray type provides access to the elements in the array in the
+following ways:
+
+Property Types[Index : Integer] : TJSONType;
+ Indexed access to the types of the elements in the array.
+Property Nulls[Index : Integer] : Boolean 
+ Checks if the Index-the element is NULL.
+Property Integers[Index : Integer] : Integer
+  Read/Write element values as integers.
+Property Int64s[Index : Integer] : Int64 
+  Read/Write element values as 64-bit integers.
+Property Strings[Index : Integer] : TJSONStringType;
+  Read/Write element values as strings.
+Property Floats[Index : Integer] : TJSONFloat ;
+  Read/Write element values as floats (doubles).
+Property Booleans[Index : Integer] : Boolean;
+  Read/Write element values as booleans.
+Property Arrays[Index : Integer] : TJSONArray;
+  Read/Write element values as arrays.
+Property Objects[Index : Integer] : TJSONObject;
+  Read/Write element values a strings
+
+Reading an element as a type which is incompatible, will result in an
+exception. For instance if element 5 is an object value, then the following
+will result in an exception:
+  i:=i+Array.Integers[5]
+
+The TJSONObject type similarly provides access to the elements in the array
+using the member names:
+property Names[Index : Integer] : TJSONStringType;
+  Indexed access to the member names.
+property Elements[AName: string] : TJSONData;
+  Read/Write a member as a raw TJSONData value.
+Property Types[AName : String] : TJSONType Read GetTypes;
+  Read/Write the type of a member.
+Property Nulls[AName : String] : Boolean;
+  Read/Write a member as a NULL value.
+Property Floats[AName : String] : TJSONFloat;
+  Read/Write a member as a float value (double)
+Property Integers[AName : String] : Integer;
+  Read/Write a member as an integer value
+Property Int64s[AName : String] : Int64;
+  Read/Write a member as an 64-bit integer value
+Property Strings[AName : String] : TJSONStringType;
+  Read/Write a member as a string value.
+Property Booleans[AName : String] : Boolean;
+  Read/Write a member as a boolean value.
+Property Arrays[AName : String] : TJSONArray;
+  Read/Write a member as an array value.
+Property Objects[AName : String] : TJSONObject
+  Read/Write a member as an object value.
+
+Members can be added with the Add() call, which exists in various overloaded
+forms:
+   function Add(const AName: TJSONStringType; Const AValue): Integer;
+Where the type of AVAlue is one of the supported types: 
+integer, int64, double, string, TJSONArray or TJSONObject.
+
+The Delete() call deletes an element from an array or object.
+
+Important remark:
+The array and object classes own their members: the members are destroyed as
+they are deleted. For this, the Extract() call exists: it removes an
+element/member from the array/object, without destroying it.
+
+The JSONSCanner unit contains a scanner for JSON data: TJSONScanner. 
+Currently it does not support full unicode, only UTF-8 is supported.
+
+The JSONParser unit contains the parser for JSON data: TJSONParser. 
+It uses to scanner to read the tokens. The scanner is created automatically.
+
+
+The Parse method will parse the data that was passed to the parser and will
+return the JSON value.
+
+Sample use:
+
+Var
+  P : TJSONParser;
+  S : String;
+  D : TJSONObject;
+
+begin
+  P:=TJSONParser.Create('{ "top": 10, "left": 20}');
+  try
+    D:=P.Parse as TJSONObject;
+    Writeln('Top : ',D.Integers['top']);
+    Writeln('Left : ',D.Integers['left']);
+    D.free;
+  Finally
+    P.free;
+  end;
+end;
+
+Note that the member names are case sensitive. 
+
+As an alternative, a stream may be passed to the constructor of TJSONParser.
+
+The scanner and parser support the 'Strict' property. 
+Strict JSON syntax requires the member names of an object to be strings:
+{ "top": 10, "left": 20}
+However, due to the sloppy definition of Javascript (and hence JSON), 
+the following type of JSON notation is frequently encountered:
+{ top: 10, left: 20}
+By default, this sloppy notation is accepted. Setting 'Strict' to true will
+reject this.
+
+A second effect of the Strict property is the requirement of " as a string
+delimiter. A single quote is also often found in Javascript and JSON:
+{ title: 'A nice title' }
+By default, this is accepted. Setting 'Strict' to true will reject this.