File Structure

A Slint Source File

A .slint source file is a sequence of zero or more top-level items, separated only by whitespace and comments.[sls.file.source-file]

A source file that contains only whitespace and comments is well-formed and defines no components.[sls.file.source-file.empty]

Top-Level Items

A top-level item is a component definition.[sls.file.top-level-item]

Component Definitions

A component definition has one of the following two forms:[sls.file.component.definition-forms]

component Name { /* component body */ }
component Name inherits Base { /* component body */ }

slint

The identifier following the component keyword is the name of the component.[sls.file.component.name]

The first form defines a component with no explicit base; the second form defines a component that inherits from the element type named by Base.[sls.file.component.inherits]

A component that inherits extends its base: an instance of the component is an element of type Base.[sls.file.component.inherits.meaning]

The bindings of the component body apply to that element, and the elements instantiated in the component body become children of the element.[sls.file.component.inherits.body-applies]

The component has the properties of Base in addition to those declared in its body, and a binding in the component body may bind them.[sls.file.component.inherits.properties]

The identifier Base shall resolve to a built-in element or to a component defined earlier in the file.[sls.file.component.inherits.base]

The braces { and } delimit the component body.[sls.file.component.body-braces]

Component Bodies

A component body is a sequence of zero or more element instantiations, bindings, and property declarations, separated only by whitespace and comments.[sls.file.component.body]

A component body that contains no element instantiations is well-formed.[sls.file.component.body.empty]

Element Instantiations

An element instantiation has the form:[sls.file.element.instantiation-form]

TypeName { /* element body */ }

slint

The identifier TypeName shall resolve to a built-in or user-defined component.[sls.file.element.instantiation-typename]

An instantiation may be preceded by an id and :=, as in foo := Rectangle { }, naming the element within the component, so that a reference can reach its properties.[sls.file.element.id]

An id shall be unique within the component.[sls.file.element.id.unique]

The names self, parent, and root are reserved and shall not be used as an id.[sls.file.element.id.reserved]

Neither Window nor a component that directly or indirectly inherits Window shall be instantiated as an element.[sls.file.element.no-window-instantiation]

The braces delimit the element body. An element body is a sequence of zero or more nested element instantiations and bindings, separated only by whitespace and comments.[sls.file.element.body]

A nested element instantiation is a child of the element instantiation in whose body it appears. The child relationship forms a tree rooted at the elements that appear directly in a component body.[sls.file.element.tree]

Example

The following is a complete, well-formed .slint source file:[sls.file.example.intro]

export component Hello inherits Window {
    Rectangle {
    }
    Rectangle {
    }
}

slint

It exports one component, Hello, which inherits from Window and whose body contains two top-level Rectangle instantiations.[sls.file.example.description]