1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142

use syn::parse::ParseStream;
use syn::spanned::Spanned;
use syn::{token, Error, Ident, Token};

use crate::widgets::{
    parse_util, AssignProperty, Attrs, ConditionalWidget, ParseError, Property, PropertyName,
    PropertyType, SignalHandler, Widget, WidgetFunc,
};

impl Property {
    pub(super) fn parse(input: ParseStream<'_>) -> (Self, bool) {
        match Self::parse_failing(input) {
            Ok(prop) => (prop, false),
            Err(err) => (
                Self {
                    name: PropertyName::Ident(parse_util::string_to_snake_case("invalid_property")),
                    ty: PropertyType::ParseError(err),
                },
                true,
            ),
        }
    }

    fn parse_failing(input: ParseStream<'_>) -> Result<Self, ParseError> {
        // Handle `#[attrs]`
        let mut attributes: Option<Attrs> = if input.peek(Token![#]) {
            Some(input.parse()?)
        } else {
            None
        };

        // parse `if something { WIDGET } else { WIDGET}` or a similar match expression.
        if input.peek(Token![if]) || input.peek(Token![match]) {
            return Ok(Property {
                name: PropertyName::RelmContainerExtAssign(input.span()),
                ty: PropertyType::ConditionalWidget(ConditionalWidget::parse_with_name(
                    input,
                    None,
                    attributes.take(),
                    None,
                )?),
            });
        }

        // Parse path, ident or function
        let func = WidgetFunc::parse(input)?;

        // `gtk::Box { ... }`, `data.init_widget() -> gtk::Button { ... }` or `gtk::Box,`
        if input.peek(token::Brace) || input.peek(Token![->]) || input.peek(Token![,]) {
            let span = func.span();
            let ty =
                PropertyType::Widget(Widget::parse_for_container_ext(input, func, attributes)?);

            Ok(Property {
                name: PropertyName::RelmContainerExtAssign(span),
                ty,
            })
        } else {
            let name = func.into_property_name()?;

            // check for property[a, b, c]: ...
            let mut args = if input.peek(token::Bracket) {
                let paren_input = parse_util::brackets(input)?;
                Some(paren_input.parse()?)
            } else {
                None
            };

            // look for event handlers: signal[cloned_data, ...] => move |a, ...| { ... }
            let ty = if input.peek(Token! [=>]) {
                let _arrow: Token![=>] = input.parse()?;
                PropertyType::SignalHandler(SignalHandler::parse_with_args(input, args.take())?)
            }
            // look for widgets
            else if (input.peek(Token![=])
            || input.peek3(Token![=])
            || (input.peek(Token![:]) && input.peek2(Token![mut]) && input.peek3(Ident)))
            // Don't interpret `property: value == other,` as a widget
            && !input.peek3(Token![==])
            {
                let is_conditional = if input.peek(Token![=]) {
                    let _token: Token![=] = input.parse()?;
                    input.peek(Token![if]) || input.peek(Token![match])
                } else {
                    let _colon: Token![:] = input.parse()?;
                    input.peek3(Token![if]) || input.peek3(Token![match])
                };
                // match expression
                if is_conditional {
                    PropertyType::ConditionalWidget(ConditionalWidget::parse(
                        input,
                        attributes.take(),
                        args.take(),
                    )?)
                } else {
                    PropertyType::Widget(Widget::parse(input, attributes.take(), args.take())?)
                }
            }
            // look for properties or optional properties (?)
            else if input.peek(Token! [:]) || input.peek(Token! [?]) {
                // look for ? at beginning for optional assign
                PropertyType::Assign(AssignProperty::parse(
                    input,
                    attributes.take(),
                    args.take(),
                )?)
            } else {
                return Err(input.error("Unexpected syntax.").into());
            };

            // Attributes must have been set to `None` by `take()`
            if let Some(attrs) = attributes {
                if let Some(first_attr) = attrs.inner.first() {
                    return Err(Error::new(
                        first_attr.span(),
                        "No attributes allowed in the following expression.",
                    )
                    .into());
                }
            }

            // Arguments must have been set to `None` by `take()`
            if let Some(args) = args {
                if let Some(first_arg) = args.inner.first() {
                    return Err(Error::new(
                        first_arg.span(),
                        "No arguments allowed in this expression.",
                    )
                    .into());
                }
            }

            if !input.is_empty() && !input.peek(Token![,]) {
                Err(input
                    .error("expected `,`. Did you confuse `=` with`:`?")
                    .into())
            } else {
                Ok(Property { name, ty })
            }
        }
    }
}