Conditionals

Control the order of execution in your scripts using conditionals and loops. DWScript combines traditional Pascal readability with enhancements like for..in and loop step.

If Statements

The if statement executes a block if a condition is true. The else part is optional.

var x := 10;

if x > 5 then
  PrintLn('Greater than 5')
else
  PrintLn('Less or equal');

// Nested
if x > 0 then begin
  if x < 100 then
     PrintLn('In range');
end;
Result
Greater than 5
In range

Case Statements

case is used for multi-way branching. In DWScript, it supports Integers, Characters, Enumerations, Strings, Booleans, Variants, and Floats.

var val := 7;
case val of
  0:          PrintLn('Zero');            // Single value
  1..5, 7:    PrintLn('Range and Seven'); // Mixed range and value
  10, 20, 30: PrintLn('Specific list');   // List of values
else 
  PrintLn('Other');                       // Default branch
end;

var fruit := 'Grape';
case fruit of
  'Apple', 'Grape', 'Orange': PrintLn('First group');
  'Peach', 'Plum', 'Watermelon': PrintLn('Second group');
else
  PrintLn('Unknown fruit');
end;

// Case with Floats and Ranges
var f := 2.5;
case f of
  0..0.99:   PrintLn('Small');
  1.0..2.99: PrintLn('Medium'); // Matches
else 
  PrintLn('Large');
end;
Result
Range and Seven
First group
Medium

Float Boundary Precision

Floating point ranges in case statements use inclusive boundaries (using standard <= and >= logic).

However, because floating-point math can have precision issues (e.g., 1.0 might be stored as 0.99999999999998), using case for exact boundaries can be risky. For mission-critical boundary logic, using if with an explicit epsilon or strict inequalities is recommended.

With Statements

The with statement in DWScript differs from traditional Pascal. It is used as a scoping construct to create local aliases for expressions, improving readability and reducing repetition.

// Use 'with' to simplify local access to complex expressions
with fullName := WebRequest.QueryField['first_name'] + ' ' + WebRequest.QueryField['last_name'] do begin
  if fullName.Trim <> '' then
     PrintLn('Welcome, ' + fullName);
end;

// Declare multiple locals to use within a block
with a := 10, b := 20, c := 30 do begin
  PrintLn('Sum: ' + (a + b + c).ToString);
end;
Result
Sum: 60

Important Difference from Delphi: In traditional Delphi, the with statement implicitly introduces an object's members into the current scope (e.g., with myPoint do X := 10;).

In DWScript, the with statement does not introduce members into the current scope. Instead, it requires an explicit alias (e.g., with p := myPoint do p.X := 10;).

This design decision was made to avoid the "scope pollution" and ambiguity found in traditional Pascal, where it can be unclear whether a variable name refers to a local variable or a member of the object in the with block.

The variables declared in a with statement are only visible within its do block.

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