Cross Ref > Operators

ASP Classic uses = for it's assignment operator.

FullName = "Randy Spitz"
Age = 38

Delphi uses := for it's assignment operator.

var

  FullName: String;

  Age: Integer;

begin

  FullName := "Randy Spitz";
  Age := 38;

end

Save as VB Classic. Common comparison operators:

//Does ASP evaluate the math correctly? No!

If .1 + .1 + .1 = .3 Then
  Response.Write "correct"
Else
  Response.Write "not correct"
End If

 ASP Classic Comparison Operators (=, <>)

Common comparison operators:

//Does Delphi evaluate the math correctly? Yes!

//Refer to math.pas MaxSingle for more info.

if (0.1 + 0.1 + 0.1 = 0.3) then
  ShowMessage('correct')
else
  ShowMessage('not correct')

 Delphi Comparison Operators (=, <>)

In ASP Classic, you have to add an empty string to the value being compared in order to get consistent results. For example, add &"" to your string varilable or it's code equivalent &vbNullString. Then compare to an empty string or verify it's length to 0 with Len.

If s&"" = "" Then
  Response.Write("<br>Quotes with &'' say null is empty")
End If

 
If Len(s&"") = 0 Then
  Response.Write("<br>Len with &'' says null is empty")
End If

If Len(s&vbNullString) = 0 Then
  Response.Write("<br>Using vbNullString also works!")
End If

 ASP Classic Empty String Check (Len(s&vbNullString))  

Length() or SizeOf() will correctly identify an unassigned string variable or an empty string.

if length(s) = 0 then
  ShowMessage('empty string');

Same as VB. ASP Classic logical operators:

ASP Classic never short circuits. Given the expression this or that as well as this and that, if this evaluates to false, then that is still executed.

'Given expressions a, b, c, and d:

If Not (a and b) and (c or d) Then

  'Do something.

End If

 ASP Classic Logical Operators (and, or, not)  

Delphi logical operators:

The Delphi compiler default is to short circuit multi argument boolean expressions when the result is known before the evaluation completes. To disable short circuiting, use the {$B+} compiler directive. To reset it back to the compiler default of short circuting, use the {$B-} compiler directive.

//Given expressions a, b, c, and d:

if Not (a and b) and (c or d) then

  //Do something.

 Delphi Logical Operators  

Although you can use either a & or a + to concatenate values, my preference is to use a + because more languages use it. However, if you use & then some type conversions are done for you. If you use + you will sometimes have to cast a value to concatenate it. For example, you will have to use CStr to cast a number to a string if you use the + operator as a concatenation operator.

Dim FirstName
Dim LastName

FirstName  = "Mike"
LastName  = "Prestwood"

Response.Write "Full name: " & FirstName & " " + LastName

Response.Write "2+2=" + CStr(2+2)

Use the + operator to concatenate two strings. Use IntToStr to convert an integer to a string and FloatToStr to convert a floating point number to a string.

var 

  FirstName : String; 

  LastName : String;

begin 

  FirstName := 'Mike'; 

  LastName := 'Prestwood';

  ShowMessage('Full name: ' + FirstName + ' ' + LastName);

  ShowMessage(FloatToStr(3.2));

end;

An operation with only one operand (a single input) such as +, -, and Not.

 ASP Classic Unary Operators

An operation with only one operand (a single input). In Object Pascal, a unary operator has the highest precedence and always precedes its operand (for example, -B), except for the  ^ pointer operator, which follows its operand (for example, P^). In addition to the obvious +, -, and Not operators, Delphi also offers:

The TYPE operator is also a unary operator and is valuated at compile time. The TYPE operator returns the size in bytes of the operand,