Author: Tercio Ferdinando Gaudencio Filho

Replacement for the C ternary conditional operator "?"

Answer:

Solve 1:

Original functions by Project JEDI Code Library (JCL). 

It's better(read faster) than use Variant Type. 

Ps.: Portuguese comments. 
1   
2   //*******************************************************
3   // Declara??o
4   // Substitui??o do operador "?" em C
5   //*******************************************************
6   
7   function Iff(const Condition: Boolean; const TruePart, FalsePart: Boolean): Boolean;
8     overload;
9   function Iff(const Condition: Boolean; const TruePart, FalsePart: Byte): Byte;
10    overload;
11  function Iff(const Condition: Boolean; const TruePart, FalsePart: Cardinal):
12    Cardinal; overload;
13  function Iff(const Condition: Boolean; const TruePart, FalsePart: Char): Char;
14    overload;
15  function Iff(const Condition: Boolean; const TruePart, FalsePart: Extended):
16    Extended; overload;
17  function Iff(const Condition: Boolean; const TruePart, FalsePart: Integer):
18    Integer; overload;
19  function Iff(const Condition: Boolean; const TruePart, FalsePart:
20    Pointer): Pointer; overload;
21  function Iff(const Condition: Boolean; const TruePart, FalsePart:
22    string): string; overload;
23  {$IFDEF SUPPORTS_INT64}
24  function Iff(const Condition: Boolean; const TruePart, FalsePart:
25    Int64): Int64; overload;
26  {$ENDIF SUPPORTS_INT64}
27  
28   //*******************************************************
29   // Fun?ões
30   // Substitui??o do operador "?" em C
31   //*******************************************************
32  
33  function Iff(const Condition: Boolean; const TruePart, FalsePart:
34    Boolean): Boolean; overload;
35  begin
36    if Condition then
37      Result := TruePart
38    else
39      Result := FalsePart;
40  end;
41  //*******************************************************
42  
43  function Iff(const Condition: Boolean; const TruePart, FalsePart:
44    Byte): Byte; overload;
45  begin
46    if Condition then
47      Result := TruePart
48    else
49      Result := FalsePart;
50  end;
51  //*******************************************************
52  
53  function Iff(const Condition: Boolean; const TruePart, FalsePart:
54    Cardinal): Cardinal; overload;
55  begin
56    if Condition then
57      Result := TruePart
58    else
59      Result := FalsePart;
60  end;
61  //*******************************************************
62  
63  function Iff(const Condition: Boolean; const TruePart, FalsePart:
64    Char): Char; overload;
65  begin
66    if Condition then
67      Result := TruePart
68    else
69      Result := FalsePart;
70  end;
71  //*******************************************************
72  
73  function Iff(const Condition: Boolean; const TruePart, FalsePart:
74    Extended): Extended; overload;
75  begin
76    if Condition then
77      Result := TruePart
78    else
79      Result := FalsePart;
80  end;
81  //*******************************************************
82  
83  function Iff(const Condition: Boolean; const TruePart, FalsePart:
84    Integer): Integer; overload;
85  begin
86    if Condition then
87      Result := TruePart
88    else
89      Result := FalsePart;
90  end;
91  //*******************************************************
92  
93  function Iff(const Condition: Boolean; const TruePart, FalsePart:
94    Pointer): Pointer; overload;
95  begin
96    if Condition then
97      Result := TruePart
98    else
99      Result := FalsePart;
100 end;
101 //*******************************************************
102 
103 function Iff(const Condition: Boolean; const TruePart, FalsePart:
104   string): string; overload;
105 begin
106   if Condition then
107     Result := TruePart
108   else
109     Result := FalsePart;
110 end;
111 //*******************************************************
112 {$IFDEF SUPPORTS_INT64}
113 
114 function Iff(const Condition: Boolean; const TruePart, FalsePart:
115   Int64): Int64; overload;
116 begin
117   if Condition then
118     Result := TruePart
119   else
120     Result := FalsePart;
121 end;
122 {$ENDIF SUPPORTS_INT64}



Solve 2:

Delphi 6+ has the following functions: 
123 
124 function IfThen(AValue: Boolean; const ATrue: Integer; const AFalse: Integer = 0):
125   Integer; overload;
126 
127 function IfThen(AValue: Boolean; const ATrue: Int64; const AFalse: Int64 = 0): 
128 Int64;
129   overload;
130 
131 function IfThen(AValue: Boolean; const ATrue: Double; const AFalse: Double = 0.0):
132   Double; overload;
133 
134 function IfThen(AValue: Boolean; const ATrue: string; const AFalse: string =
135   ''): string; overload;