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Expressions and Operators

Operators​

Increment and Decrement Operators​

The operands' types of the increment and decrement operators must be integer, float, or any.

  • Postfix Increment/Decrement Operators
    The value is incremented or decremented by 1, and the original value is returned.

    let x = 1;
    print(x++); // 1
    print(x);   // 2

    let y = 1.0;
    print(y--); // 1.0
    print(y);   // 0.0

  • Prefix Increment/Decrement Operators
    The value is incremented or decremented by 1, and the updated value is returned.

    let x = 1;
    print(++x); // 2
    print(x);   // 2

Unary Operators​

BlueScript supports the following unary operators:

  • + (Unary plus)

    It returns the value of its operand. The operand's type must be integer, float, or any.

  • - (Unary negation)

    It returns the negation of its operand. The operand's type must be integer, float, or any.

  • ~ (Bitwise NOT)

    The operand's type must be integer or any.

  • ! (Logical NOT)

    The operand's type can be any kind of type.

The following example shows the use of the unary negation.

print(-3)  // -3

Arithmetic Operators​

The operands' types must be integer, float, or any. If either the left operand or the right operand is any, the resulting type is any. If either left or right is float, the resulting type is float. Otherwise, it is integer.

  • + (Addition)

  • - (Subtraction)

  • * (Multiplication)

  • / (Division)

  • % (Modulus)

    The operands must be an integer value or an any-type value holding an integer value.

  • ** (Exponentiation)

    The operands are converted into double values, and pow() in C computes the result.

Relational Operators​

The operands' types must be integer, float, string, or any. The resulting type is boolean. Both operands share the same type or any-type. If a left or right operand is any-type, the value of the other operand is converted into an any-type value before comparison.

  • < (Less than)
  • > (Greater than)
  • <= (Less than or equal to)
  • >= (Greater than or equal to)

Equality Operators​

  • == and === are used as equality operators. Their semantics is the same as the === operator in JavaScript.
  • != and !== are used as inequality operators. Their semantics is the same as the !== operator in JavaScript.

If either the left operand or the right operand is a boolean type, the other operand must be also boolean type.

Bitwise Shift Operators​

The operands' types must be integer. It may not be any-type. The type of the resulting value is integer.

  • << (Left shift)
  • >> (Right shift)
  • >>> (Unsigned right shift)

Binary Bitwise Operators​

The operands' types must be integer. It may not be any-type. The type of the resulting value is integer.

  • & (AND)
  • | (OR)
  • ^ (XOR)

Binary Logical Operators​

  • && (Logical AND)
  • || (Logical OR)

Type operators​

  • typeof

    It returns the static type name of its operand. Unlike JavaScript, it is not a dynamic type name.

  • instanceof

    It checks whether the left operand is an instance of the class given as the right operand or its subclass. The right operand may be string or Array. The type of the left operand must be a class type, string, an array type, or any.

obj instanceof Array results in true when obj is an array object no matter what its element type is.

Ternary Operator​

The ternary operator ? : is used for conditional expressions:

let result = condition ? trueValue : falseValue;

Assignment Operators​

BlueScript supports the following assignment operators:

  • =

  • +=, -=, *=, /=

    Compound assignment operators. The operands' type must be integer, float, or any.

  • %=

    The operands' type must be integer or any.