Portugol Studio 2.0

01 · Scope

About Portugol Studio 2.0

Portugol is a name used for several pseudolanguages. This page covers Portugol Studio 2.0 specifically; its rules do not define one universal standard for every pseudolanguage called Portugol.

The rules presented here describe the Portugol Studio 2.0 pseudolanguage and follow the sources listed at the end of this reference.

02 · Organization

Program structure

A file starts with programa and a block enclosed in braces. Library includes appear at the beginning of the block; global declarations and functions may follow. The conventional entry point is a function named inicio.

programa {
    inclua biblioteca Matematica --> mat

    const inteiro tentativas = 3
    inteiro acertos = 0

    funcao inicio() {
        escreva("Welcome to the exercise")
    }
}

Functions, conditions and loops use { and } for blocks. Semicolons separate the three fields in a para header; common examples place one statement on each line without ending every statement with a semicolon.

03 · Writing

Names, comments and literals

• Identifiers start with an ASCII letter or underscore; following characters may be ASCII letters, digits or underscores. The published grammar does not allow accented letters in identifiers.
• Keywords are written without accents and the grammar recognizes their lowercase forms, such as programa, funcao and enquanto.
• Line comments start with //; block comments are enclosed by /* and */.
• Real numbers use a period as the decimal separator. Strings use double quotes and individual characters use single quotes; the lexer also defines escapes and hexadecimal literals.
• Logical values are verdadeiro and falso.

// line comment
/* block
   comment */
cadeia mensagem = "Hello"
caracter inicial = 'A'
real media = 7.5
logico aprovado = verdadeiro

04 · Data

Types, variables and constants

Place the type before the name. A declaration can group names of the same type and include an initial expression. The const keyword marks constant declarations. Values and types must be compatible.

inteiro idade = 18, ano
real altura = 1.72
const real pi_aproximado = 3.14
cadeia nome = "Lia"
logico concluiu = falso

A variable declared inside a function or block has local scope; declarations in the main program outside functions are global. Declarations also allow vector and matrix initializers, described in Vectors and matrices.

05 · Expressions

Operators and precedence

The official grammar defines operators through recursive alternatives, but it does not publish a clear precedence table for every combination. Use parentheses to make evaluation order explicit, especially when mixing comparisons, logic and bitwise operations.

06 · Interaction

Input and output

escreva displays one or more expressions. To start a new line, include the \n escape sequence in a string passed to the function. leia reads values into variables. The predefined function limpa() clears the output area.

programa {
    funcao inicio() {
        cadeia nome
        escreva("What is your name? ")
        leia(nome)
        escreva("Hello, ", nome, "!\n")
    }
}

The way data is displayed and read depends on the functions and libraries available in the runtime described by the references.

07 · Decisions

Conditions and selection

se runs a branch when a logical expression is true; senao defines the alternative branch. Blocks can contain multiple statements. Multiway selection uses escolha, caso labels and the fallback case contrario.

se (nota >= 7) {
    escreva("Passed\n")
} senao {
    escreva("Keep practicing\n")
}

escolha (opcao) {
    caso 1:
        escreva("Start\n")
        pare
    caso contrario:
        escreva("Unknown option\n")
}

pare ends the current escolha case or exits a loop. Use a logical expression as the condition.

08 · Loops

Repetition

Portugol Studio 2.0 defines conditional loops and a loop with initialization, condition and increment fields:

inteiro contador = 1
enquanto (contador <= 3) {
    escreva(contador, "\n")
    contador++
}

faca {
    contador--
} enquanto (contador > 0)

para (inteiro i = 0; i < 3; i++) {
    escreva(i, "\n")
}

enquanto checks before each repetition; faca ... enquanto checks after the block. In para, semicolons separate fields that can initialize a variable, check a condition and update a counter. pare exits the current loop.

09 · Collections

Vectors and matrices

Vectors use one index in square brackets; matrices use two. An explicit size must be a positive integer constant expression; in declarations with an initializer, the size can be inferred. The grammar also allows matrices initialized by rows.

programa {
    funcao inicio() {
        inteiro notas[3] = {8, 9, 10}
        inteiro quadro[2][2] = {{1, 2}, {3, 4}}
        escreva(notas[0], "\n")
        escreva(quadro[1][0], "\n")
    }
}

Indices are integer expressions. Function parameters can declare dimensions without fixed sizes, for example inteiro valores[] or inteiro tabela[][].

10 · Reuse

Functions and parameters

A function may declare its return type before its name; omitting the type means it returns no value, which may also be written as vazio. Parameters have a type and name, can be comma-separated, and may receive vectors or matrices. An & before the name marks a reference parameter.

funcao inteiro dobrar(inteiro valor) {
    retorne valor * 2
}

funcao atualizar(inteiro &total, inteiro acrescimo) {
    total += acrescimo
}

funcao inicio() {
    inteiro resultado = dobrar(4)
    atualizar(resultado, 1)
    escreva(resultado, "\n")
}

retorne ends the function and may return an expression. The official reference describes calls in expressions, functions with return values and functions without one.

11 · Standard resources

Portugol Studio 2.0 libraries

Include a library with inclua biblioteca Name; an alias may follow -->. Calls use the name or alias followed by a period. The table summarizes the pseudolanguage modules documented in the sources for this reference; class documentation lists signatures, parameters and constants.

inclua biblioteca Matematica --> mat

funcao inicio() {
    escreva(mat.potencia(2, 3), "\n")
}

The libraries belong to the Portugol Studio 2.0 reference environment; not every library fits every interpreter or execution context.

Signatures and results

The calls below use the mat alias from the previous example. Functions return values that can be assigned to variables or combined in expressions.

inclua biblioteca Texto --> txt

funcao inicio() {
    cadeia palavra = "logica"
    escreva(txt.numero_caracteres(palavra), "\n")
    escreva(txt.caixa_alta(palavra), "\n")
    escreva(txt.extrair_subtexto(palavra, 0, 3), "\n")
}

Output: 6, LOGICA and log, each on its own line.

inclua biblioteca Tipos --> tipos

funcao inicio() {
    escreva(tipos.cadeia_e_inteiro("101", 2), "\n")
    escreva(tipos.cadeia_para_inteiro("101", 2), "\n")
}

Output: verdadeiro and 5. The first call validates the binary notation; the second converts the same value to an integer.

12 · Example

Complete program

This example combines a declaration, input and output, a condition, a function and a logical expression:

programa {
    funcao logico eh_par(inteiro numero) {
        retorne numero % 2 == 0
    }

    funcao inicio() {
        inteiro valor
        escreva("Enter an integer: ")
        leia(valor)

        se (eh_par(valor)) {
            escreva("The number is even\n")
        } senao {
            escreva("The number is odd\n")
        }
    }
}

13 · Reading tips

Common mistakes and how to avoid them

• Mixing assignment and equality: use = to assign and == to compare values.
• Forgetting the separators in a para loop: initialization, condition and update fields are separated by semicolons.
• Using an index outside a vector: indices start at zero; a vector of size 3 has positions 0 through 2.
• Expecting a function from another library: include the module with inclua biblioteca Name and use its name or alias before the period.
• Confusing length with the last index: a six-character string has last index 5; in extrair_subtexto, the final index is the boundary and is not included in the result.
• Using pare anywhere: it ends the current loop or selection case; outside those contexts, it does not replace retorne.

14 · Further reading

Portugol Studio 2.0 pseudolanguage references

Portugol Studio 2.0 originates from Portugol Studio. That project appears in this section only as a source for the references used to document the pseudolanguage.

• The official Portugol Studio repository identifies the pseudolanguage as Portugol Studio 2.0.
• The official grammar and official lexer.
• The official input/output help, including the \n newline escape, and its semantic analyzer, which lists predefined functions.
• Standard library source code and documented functions; see Matematica, Texto, Tipos and Util directly.

These references belong to separate projects. Check them for behavior and compatibility details before relying on a specific function.