Operators

Arithmetic operators

An arithmetic expression combines two operands with +, -, or *.[sls.op.form]

+ and - require both operands to have the same type.[sls.op.additive]

* multiplies a value by a number.[sls.op.multiplicative]

* binds tighter than + and -.[sls.op.precedence]

Arithmetic saturates at the bounds of the value’s type.[sls.op.saturating]

export component Example inherits Window {
    in property <length> a;
    in property <length> b;
    out property <length> total: a + b * 2;
}

slint

Comparison operators

The operators ==, !=, <, >, <=, and >= compare two operands of a common type and produce a bool.[sls.op.comparison]

== and != test whether the operands are equal.[sls.op.comparison.equality]

<, >, <=, and >= order two numbers or lengths.[sls.op.comparison.ordering]

export component Example inherits Window {
    in property <int> a;
    in property <length> w;
    in property <length> h;
    out property <bool> equal: a == 0;
    out property <bool> different: a != 0;
    out property <bool> wider: w > h;
}

slint

Logical operators

The binary operators && and || combine two boolean operands into a boolean: && is true when both operands are true, || when either is.[sls.op.logical]

The unary operator ! negates a boolean.[sls.op.not]

The operands must be bool; no other type is coerced to bool.[sls.op.bool-operands]

export component Example inherits Window {
    in property <bool> a;
    in property <bool> b;
    out property <bool> both: a && b;
    out property <bool> either: a || b;
    out property <bool> neither: !a && !b;
}

slint

Unary operators

The prefix operators are +, -, and !.[sls.op.prefix]

A unary + or - applies to a number or a length, and - negates it.[sls.op.unary]

export component Example inherits Window {
    in property <length> w;
    in property <bool> flag;
    out property <length> negated: -w;
    out property <bool> toggled: !flag;
}

slint

Ternary operator

condition ? value1 : value2 evaluates condition, a boolean, and yields value1 when it is true and value2 otherwise.[sls.op.ternary]

Both branches have the same type, which becomes the type of the whole expression.[sls.op.ternary.type]

A conditional associates to the right, so a ? b : c ? d : e groups as a ? b : (c ? d : e).[sls.op.ternary.assoc]

export component Example inherits Window {
    in property <bool> on;
    in property <color> active;
    in property <color> idle;
    out property <color> tint: on ? active : idle;
}

slint