Variables and types

Every variable in NeoObjectPascal has a declared type. The declaration uses the var keyword, followed by the name, a colon, and the type:

var idade: Integer;
var nome: String;

Values are assigned with the := operator (don't confuse it with =, which is the equality operator):

begin
    var idade: Integer;
    idade := 30;
    WriteLn("Idade: ", idade);
end.

Saída

 Idade: 30 

Where to declare

You can declare variables in two places:

• At the top of the file, before the main block.
• Inside a block begin ... end, as an ordinary statement.

var total: Integer;   // top-level declaration

begin
    total := 100;
    var imposto: Integer;   // declaration inside the block
    imposto := total / 10;
    WriteLn("Imposto: ", imposto);
end.

Saída

 Imposto: 10 

The ten types

NeoObjectPascal has ten built-in types:

Type	Description	Literal examples
Integer	Whole numbers	0, 42, -7
Real	Floating-point numbers (double precision)	3.14159, 5.0, -0.5
String	Text	"olá", 'mundo'
Boolean	Logical value	true, false
Array	Ordered collection of values	[1, 2, 3], ["a", "b"]
Object	Generic type (instances, JSON/CSV, assorted values)	new Pessoa("Ana")
Date	Calendar date (ISO yyyy-MM-dd)	today(), date(2026,12,25)
Time	Time of day (HH:mm:ss)	currentTime(), time(10,30,0)
DateTime	Combined date and time	now()
Currency	Exact decimal money (no floating-point error)	currency(199.90)

On top of these, Double and Float are aliases of Real (64-bit floating point) — use whichever name you prefer. The Date, Time, DateTime and Currency types are covered in detail in Dates, times & currency.

Literals and details of each type

Integer and Real

Integers are written directly: 10, -3, 0. Real numbers require digits on both sides of the decimal point:

begin
    var meio: Real;
    meio := 0.5;    // correct
    WriteLn(meio);
end.

Saída

 0.5 

Real requires complete digits

Write 5.0, never 5. — the second form is invalid. Likewise, use 0.5 and not .5.

When you mix Integer and Real in an expression, the integer is automatically promoted to Real. The same happens when assigning an integer to a Real variable:

begin
    var x: Real;
    x := 5;          // 5 becomes 5.0
    var y: Real;
    y := 2 * 3.5;    // Real result
    WriteLn("x = ", x);
    WriteLn("y = ", y);
end.

Saída

 x = 5.0 y = 7.0 

String

Strings can use double quotes or single quotes — both work the same way:

begin
    var a: String;
    var b: String;
    a := "aspas duplas";
    b := 'aspas simples';
    WriteLn(a);
    WriteLn(b);
end.

Saída

 aspas duplas aspas simples 

The + operator concatenates strings. If either side is a String, + joins the values instead of adding them:

begin
    var nome: String;
    nome := "Mundo";
    WriteLn("Olá, " + nome + "!");
end.

Saída

 Olá, Mundo! 

Boolean

A Boolean holds true or false (also accepted in uppercase, such as True or TRUE):

begin
    var ativo: Boolean;
    ativo := true;
    WriteLn("Ativo: ", ativo);
end.

Saída

 Ativo: true 

Object

Object is the language's generic type. It holds class instances, results of JSON.parse/CSV.parse, and any value whose specific type you don't need to name:

class Pessoa
    var nome: String;

    constructor Create(n: String)
    begin
        self.nome := n;
    end;

    public function saudar(): String
    begin
        return "Sou " + self.nome;
    end;
end;

var p: Object;

begin
    p := new Pessoa("Alice");
    WriteLn(p.saudar());
end.

Saída

 Sou Alice 

Choosing the type

Prefer the most specific type possible (Integer, String, etc.) and reserve Object for instances and dynamic data.

Now that you know how to declare variables, see how to combine them in Operators.