slint/internal/compiler/tests/syntax/functions/functions_purity.slint

// Copyright © SixtyFPS GmbH <info@slint.dev>
// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-Royalty-free-2.0 OR LicenseRef-Slint-Software-3.0

export component Foo {
    property <int> prop;
    callback c1;
    pure callback c2;

    function f1() {
        prop = 1;
    }
    function f2() -> int { 42 }

    pure function f3() {
        f2();
        f1();
//      ^error{Call of impure function 'f1'}

        prop /= 5;
//      ^error{Assignment in a pure context}
    }
    public function f4() {}


    pure function f5() {
        f1();
//      ^error{Call of impure function 'f1'}
        f2(); // ok, private function auto-detected as pure
        f3();
        f4();
//      ^error{Call of impure function 'f4'}
        c1();
//      ^error{Call of impure callback 'c1'}
        c2();
    }

    protected function f6() {}

    c1 => { f2() }
    c2 => {
        c1();
//      ^error{Call of impure callback 'c1'}
    }


    property <int> p1: f2();
    property <int> p2: {
        p1 = 42;
//      ^error{Assignment in a pure context}
        42
    };
    property <int> p3: {
        pw.show();
//         ^error{Call of impure function}
        fs.focus();
//         ^error{Call of impure function}
        f6();
//      ^error{Call of impure function 'f6'}
        42
    };

    pw := PopupWindow {}
    fs := FocusScope {}

    callback model() -> [int];
    for xx in model() : Rectangle {
//            ^error{Call of impure callback 'model'}
        property <int> abc: xx;
    }
}


export component Bar {
    pure callback xc1 <=> f.c1;
//  ^error{Purity of callbacks 'xc1' and 'f.c1' doesn't match}
    callback xc2 <=> f.c2;
//  ^error{Purity of callbacks 'xc2' and 'f.c2' doesn't match}
    f := Foo {
        c2 => {
            self.c1();
//               ^error{Call of impure callback 'c1'}
        }
    }
}





export Foo_Legacy := Rectangle {
//                ^warning{':=' to declare a component is deprecated. The new syntax declare components with 'component MyComponent {'. Read the documentation for more info}
    property <int> prop;
    callback c1;
    pure callback c2;

    function f1() {
        prop = 1;
    }
    function f2() -> int { 42 }

    pure function f3() {
        f2();
        f1();
//      ^warning{Call of impure function 'f1'}

        prop /= 5;
//      ^warning{Assignment in a pure context}
    }
    public function f4() {}


    pure function f5() {
        f1();
//      ^warning{Call of impure function 'f1'}
        f2(); // ok, private function auto-detected as pure
        f3();
        f4();
//      ^warning{Call of impure function 'f4'}
        c1();
//      ^warning{Call of impure callback 'c1'}
        c2();
    }

    c1 => { f2() }
    c2 => {
        c1();
//      ^warning{Call of impure callback 'c1'}
    }


    property <int> p1: f2();
    property <int> p2: {
        p1 = 42;
//      ^warning{Assignment in a pure context}
        42
    };
    property <int> p3: {
        pw.show();
//         ^warning{Call of impure function}
        fs.focus();
//         ^warning{Call of impure function}
        42
    };

    pw := PopupWindow {}
    fs := FocusScope {}
}


export Bar_Legacy := Rectangle {
//                ^warning{':=' to declare a component is deprecated. The new syntax declare components with 'component MyComponent {'. Read the documentation for more info}
    pure callback xc1 <=> f.c1;
//  ^error{Purity of callbacks 'xc1' and 'f.c1' doesn't match}
    callback xc2 <=> f.c2;
//  ^error{Purity of callbacks 'xc2' and 'f.c2' doesn't match}
    f := Foo {
        c2 => {
            self.c1();
//               ^warning{Call of impure callback 'c1'}
        }
    }
}