halimp.txt

一个Delphi解释器的例子

Automatical Import 
------------------

Step by step instructions:

1. Compile and run HALIMP.DPR

2. Import neccesary units with "unit import" dialog. 

   a) In "Input unit" field select Delphi unit which should be processed
   b) In "Output unit" field select output unit name
   c) Press button "Import unit"
   
   Program will create output file.

3. Make some changes to output file. (read "Corrections" section below)

4. Add output file to your project. And all imported objects, procedures 
   and functions will be available for use in scripts.

Manual Import
-------------

Some useful procedures:

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1) Procedure AddProc(Const Aname: String; ProcAddr: TProcType; 
	       Const Params: Array of byte);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Registers Delphi's procedure or object method in interpreter. After 
 registration procedure will be accessible in scripts.

 AName     Procedure name. For registration object method use qualified 
           name ( 'TOBJECT.FREE')
 ProcAddr  Import function address. All import functions have this form:
 
           function myinsert(slf:tobject;var s:array of variant):variant;
           where 
              slf - object (for object methods)
                s - parameters array.

 Params    Array of parameters definitions
	   Params=[2] - no parameters, otherwise type of each parameter  
           should be specified. 
           Parameter types:      
             0 - stack parameter
             1 - var parameter
             3 - open array parameter 
              (Open array is passed by interpreter to import function in 
               variant with array type. Format of this array: V[0] - array 
               size. V[1]..V[V[0]] - array items.) 
 
 Example:

  // import function 
  function myTSTRINGSAPPEND(slf:tobject;var s:array of variant):variant;
  begin
    TSTRINGS(slf).APPEND(S[0]);
  End;

  // registration call. This line should present in initialization section
  AddProc('TSTRINGS.APPEND',myTSTRINGSAPPEND,[0]);

  Other examples can be found in \HALDPK subdirectory.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2)Procedure AddFun(Const Aname: String; ProcAddr: TProcType; 
	    Const Params: Array of byte);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Registers Delphi's functions or object method in interpreter. After 
 registration function will be accessible in scripts. parameters are the 
 same as in AddProc


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
3)Procedure AddProp(Const Aname: String; ProcAddr, SetProcAddr: TProcType);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Registers non-array object properties in interpreter. 

 AName       - Object property name. For example 'TOBJECT.CLASSNAME'
 ProcAddr    - Address of interface function for reading property
 SetProcAddr - Address of interface function for writing property. 
	       Nil if property is readonly.

 Example:

 // import function for getting property  
 Function TSTRINGSget_TEXT(slf:tobject;var s:array of variant):variant;
 Begin
   Result := TSTRINGS(slf).TEXT;
 End;

 // import function for setting property
 Function TSTRINGSset_TEXT(slf:tobject;var s:array of variant):variant;
 Begin
   TSTRINGS(slf).TEXT:=S[0];
 End;

 // registration call. this line should present in initialization section
 AddProp('TSTRINGS.TEXT',TSTRINGSget_TEXT,TSTRINGSset_TEXT);


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`
4)Procedure AddArrayProp(Const Aname: String; ADim: Integer; 
	    ProcAddr, SetProcAddr: TProcType);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`
 Registers array properties in interpreter

 AName       - Object property name. For example 'TOBJECT.CLASSNAME'
 ADim  	     - array property dimension. For example if property is declared
	       as 'property A[Index1,Index2:Integer]:String' then its 
	       dimension is 2.
 ProcAddr    - Address of interface function for reading property
 SetProcAddr - Address of interface function for writing property. 
	       Nil if property is readonly.

 Example:

 // import function for getting array property
 Function TStringsget_Strings(slf:tobject;var s:array of variant):variant;
 Begin
   Result := TSTRINGS(slf).Strings[S[0]];
 End;

 // import function for setting array property
 Function TStringsset_Strings(slf:tobject;var s:array of variant):variant;
 Begin
   TStrings(slf).Strings[S[0]]:=S[1];
 End;

 // registration call. Should present in initialization section
 AddArrayProp('TSTRINGS.STRINGS',1,TSTRINGSget_Strings,TSTRINGSset_Strings);

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
5) Procedure VarToConsts(Var V: Variant; Var P: Array of tvarrec; 
	Var MaxP: Integer);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Converts variant to array of constants. Returns Maxp - high bound of array. 
 Use only in interface functions. 

 Example:
 function myTDATASETINSERTRECORD(slf:tobject;var s:array of variant):variant;
 var R:Array[0..100] of tvarrec;
     maxr:integer;
 begin
  VarToConsts(S[0],R,maxR);
  TDATASET(slf).INSERTRECORD(slice(r,maxr));
  disposeconsts(R,maxr);
 end;

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
6)Procedure disposeconsts(Var c: Array of tvarrec; size: integer);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Releases memory occupied by array of constants, converted using
 function VARTOCONSTS. Example see above.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
7) Function ObjToVar(S: TObject): Variant;
   Function OV(S: TObject): Variant;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Converts object to variant. Used when writing interface functions.

 Example:

 Function TDATABASEget_PARAMS(slf:tobject;var s:array of variant):variant;
 Begin
   Result := ObjToVar(TDATABASE(slf).PARAMS);
 End;

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
8)Function VarToObj(S: Variant): TObject;
  Function VO(S: Variant): TObject;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Converts variant to object. Used when writing interface functions.

 Example:

 Function TDATABASEset_PARAMS(slf:tobject;var s:array of variant):variant;
 Begin
   TDATABASE(slf).PARAMS:=TStrings(VarToObj(S[0]));
 End;

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
9) Procedure AddConst(Const AName: String; V: Variant);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Registers constant with name ANAME and with value V. After registration 
 constant will be accessible in scripts.

 Example: 

 // this line should present in initialization section 
 AddConst('Pi',pi);

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
10) Procedure VarToStringS(Var V: Variant; Var P: Array of String; 
	Var MaxP: Integer);
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Converts variant to array of string. Returns Maxp - high bound of array. 
 Used only in interface functions.


Corrections
------------

Automatical import procedures are not perfect. Here is some solutions 
for problems you may encounter:

1. Error: 
     Incompatible types 'Variant' and 'Pointer'
     Incompatible types 'TListSortCompare' and 'Variant'
   Solution:
     Use ObjToVar and VarToObj functions

2. Error:
     Cannot assign to readonly property
   Solution:
     Remove interface function for setting property

3. Error:
     Types of actual and formal var parameters must be identical
   Solution on example:
   Before modification:
     function myTSTRINGLISTFIND(slf:tobject;var s:array of variant):variant;
     begin
       Result := TSTRINGLIST(slf).FIND(S[0],S[1]);
     End;
   After modification:
     function myTSTRINGLISTFIND(slf:tobject;var s:array of variant):variant;
     Var
       Index:integer;	
     begin            
       Index:=S[1]; 
       Result := TSTRINGLIST(slf).FIND(S[0],Index);
       S[1]:=Index; 
     End;

4. Array properties import functions and registration call should be corrected

5. Constructor import functions and registration call should be corrected

6. If imported function contain open array as parameter then registration call
   should be corrected. (type of parameter should be changed)

7. Set and enumeration types wasn't implemented in interpreter, so it won't 
   understand functions and procedures with parameter of 'set' type.
   However enumeration types can be emulated with AddConst registration 
   procedure