Operators

DWScript supports standard Pascal operators for arithmetic, logic, and comparisons.

Assignment & Arithmetic

var a := 10;
var b := 20;

PrintLn(a + b);
PrintLn(10 div 3);
PrintLn(10 mod 3);
PrintLn(10 / 3);

30
3
1
3.33333333333333

Arithmetic Operators

Logical Operators

Used with Boolean values. Logical operators in DWScript are short-circuiting, meaning the second operand is only evaluated if the first one doesn't determine the final result.

Comparison Operators

Collection & String Inclusion

In DWScript, the in operator is highly versatile and works with sets, arrays, and strings.

Set Inclusion & Ranges

You can check if a value belongs to a set of values or a specific range.

var c := 'k';

if c in ['a'..'z', '0'..'9', '_'] then
  PrintLn('Is Alphanumeric');

var x := 5;
if x in [1..10, 20..30] then
  PrintLn('Is in range');

var s := 'Grape';
if s in ['Apple'..'Orange'] then
  PrintLn('Between Apple and Orange');

Is Alphanumeric
Is in range
Between Apple and Orange

Array Inclusion

You can check if an element exists within an array. This works for simple types, records, and objects.

var colors := ['Red', 'Green', 'Blue'];

if 'Green' in colors then
  PrintLn('Found Green');
  
if 'Yellow' not in colors then
  PrintLn('Yellow is missing');

Found Green
Yellow is missing

String Inclusion

You can check if a string contains another string using the in operator or the .Contains() method. This is more readable and idiomatic than using Pos() > 0.

var msg := 'Hello World';

// Using 'in' operator
if 'World' in msg then
  PrintLn('Found using in');

// Using .Contains method
if msg.Contains('Hello') then
  PrintLn('Found using .Contains');

// Legacy style (not recommended)
if Pos('Hello', msg) > 0 then
  PrintLn('Found using Pos');

Found using in
Found using .Contains
Found using Pos

Operator Precedence

Higher priority operators are evaluated first. When operators have the same priority, they are evaluated from left to right.

1. not, Unary -
2. *, /, div, mod, and, shl, shr, sar, %
3. ?? (Coalesce)
4. +, -, or, xor
5. =, ==, <>, !=, <, >, <=, >=, in, not in, is, as, implies
6. if then else (Ternary)

Custom Operators

You can define custom behavior for operators when working with your own types.

• Class Operators: Define operators (like +=, in) for classes.
• Record Operators: Define global operators for record value types.