Delphi Language Guide Delphi for Microsoft Win32 Delphi for the Microsoft. Net framework

Variant Type Conversions
All integer, real, string, character, and Boolean types are assignment-compatible with Variant. Expressions can be
explicitly cast as variants, and the 
VarAsType
 and 
VarCast
 standard routines can be used to change the internal
representation of a variant. The following code demonstrates the use of variants and some of the automatic
conversions performed when variants are mixed with other types.
var
   V1, V2, V3, V4, V5: Variant;
   I: Integer;
   D: Double;
   S: string;
93

---

   begin
      V1 := 1;         { integer value }
      V2 := 1234.5678; { real value }
      V3 := 'Hello world!'; { string value }
      V4 := '1000';         { string value }
      V5 := V1 + V2 + V4;   { real value 2235.5678}
      I  := V1;             { I = 1 (integer value) }
      D  := V2;              { D = 1234.5678 (real value) }
      S  := V3;              { S = 'Hello world!' (string value) }
      I  := V4;              { I = 1000 (integer value) }
      S  := V5;              { S = '2235.5678' (string value) }
   end;
The compiler performs type conversions according to the following rules.