pax_runtime/
repeat.rs

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
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
use std::collections::HashMap;
use std::iter;
use std::rc::Rc;
use_RefCell!();

use pax_runtime_api::CoercionRules;
use pax_runtime_api::{
    borrow, borrow_mut, use_RefCell, ImplToFromPaxAny, PaxValue, Property, ToPaxValue, Variable,
};

use crate::api::Layer;
use crate::{
    BaseInstance, ExpandedNode, InstanceFlags, InstanceNode, InstantiationArgs, RuntimeContext,
};

/// A special "control-flow" primitive associated with the `for` statement.
/// Repeat allows for nodes to be rendered dynamically per data specified in `source_expression`.
/// That is: for a `source_expression` of length `n`, `Repeat` will render its
/// template `n` times, each with an embedded component context (`RepeatItem`)
/// with an index `i` and a pointer to that relevant datum `source_expression[i]`
pub struct RepeatInstance {
    pub base: BaseInstance,
}

impl ImplToFromPaxAny for RepeatProperties {}
///Contains modal _vec_ and _range_ variants, describing whether the Repeat source
///is encoded as a Vec<T> (where T is a `PaxValue` properties type) or as a Range<isize>
#[derive(Default)]
pub struct RepeatProperties {
    pub source_expression: Property<PaxValue>,
    pub iterator_i_symbol: Property<Option<String>>,
    pub iterator_elem_symbol: Property<Option<String>>,
}

impl ToPaxValue for RepeatProperties {
    fn to_pax_value(self) -> PaxValue {
        PaxValue::Object(
            vec![
                (
                    "source_expression".to_string(),
                    self.source_expression.to_pax_value(),
                ),
                (
                    "iterator_i_symbol".to_string(),
                    self.iterator_i_symbol.to_pax_value(),
                ),
                (
                    "iterator_elem_symbol".to_string(),
                    self.iterator_elem_symbol.to_pax_value(),
                ),
            ]
            .into_iter()
            .collect(),
        )
    }
}

pub struct RepeatItem {
    pub elem: Property<PaxValue>,
    pub i: Property<usize>,
}

impl ToPaxValue for RepeatItem {
    fn to_pax_value(self) -> PaxValue {
        PaxValue::Object(
            vec![
                ("elem".to_string(), self.elem.get().to_pax_value()),
                ("i".to_string(), self.i.get().to_pax_value()),
            ]
            .into_iter()
            .collect(),
        )
    }
}

impl InstanceNode for RepeatInstance {
    fn instantiate(args: InstantiationArgs) -> Rc<Self>
    where
        Self: Sized,
    {
        Rc::new(Self {
            base: BaseInstance::new(
                args,
                InstanceFlags {
                    invisible_to_slot: true,
                    invisible_to_raycasting: true,
                    layer: Layer::DontCare,
                    is_component: false,
                    is_slot: false,
                },
            ),
        })
    }

    fn resolve_debug(
        &self,
        f: &mut std::fmt::Formatter,
        _expanded_node: Option<&ExpandedNode>,
    ) -> std::fmt::Result {
        f.debug_struct("Repeat").finish()
    }

    fn base(&self) -> &BaseInstance {
        &self.base
    }

    fn update(self: Rc<Self>, _expanded_node: &Rc<ExpandedNode>, _context: &Rc<RuntimeContext>) {}

    fn handle_mount(
        self: Rc<Self>,
        expanded_node: &Rc<ExpandedNode>,
        context: &Rc<RuntimeContext>,
    ) {
        self.handle_setup(expanded_node, context, true);
    }

    fn handle_control_flow_node_expansion(
        self: Rc<Self>,
        expanded_node: &Rc<ExpandedNode>,
        context: &Rc<RuntimeContext>,
    ) {
        self.handle_setup(expanded_node, context, false);
    }
}

impl RepeatInstance {
    fn handle_setup(
        self: Rc<Self>,
        expanded_node: &Rc<ExpandedNode>,
        context: &Rc<RuntimeContext>,
        is_mount: bool,
    ) {
        // No-op: wait with creating child-nodes until update tick, since the
        // condition has then been evaluated
        let weak_ref_self = Rc::downgrade(expanded_node);
        let cloned_self = Rc::clone(&self);
        let cloned_context = Rc::clone(context);
        let source_expression =
            expanded_node.with_properties_unwrapped(|properties: &mut RepeatProperties| {
                properties.source_expression.clone()
            });

        let i_symbol =
            expanded_node.with_properties_unwrapped(|properties: &mut RepeatProperties| {
                properties.iterator_i_symbol.clone()
            });
        let elem_symbol =
            expanded_node.with_properties_unwrapped(|properties: &mut RepeatProperties| {
                properties.iterator_elem_symbol.clone()
            });

        let deps = [
            source_expression.untyped(),
            i_symbol.untyped(),
            elem_symbol.untyped(),
        ];

        let last_length = Rc::new(RefCell::new(0));
        let last_elem_sym = Rc::new(RefCell::new(None));
        let last_i_sym = Rc::new(RefCell::new(None));

        let children = Property::computed_with_name(
            move || {
                let Some(cloned_expanded_node) = weak_ref_self.upgrade() else {
                    panic!("ran evaluator after expanded node dropped (repeat elem)")
                };
                let source = source_expression.get();
                let source_len = if let PaxValue::Range(start, end) = source {
                    (isize::try_coerce(*end).unwrap() - isize::try_coerce(*start).unwrap()) as usize
                } else if let PaxValue::Vec(v) = source {
                    v.len()
                } else {
                    log::warn!("source is not a vec");
                    0
                };
                if source_len == *borrow!(last_length)
                    && i_symbol.read(|i| i == &*borrow!(last_i_sym))
                    && elem_symbol.read(|e| e == &*borrow!(last_elem_sym))
                {
                    return cloned_expanded_node.children.get();
                }
                *borrow_mut!(last_length) = source_len;
                *borrow_mut!(last_i_sym) = i_symbol.get();
                *borrow_mut!(last_elem_sym) = elem_symbol.get();

                let template_children = cloned_self.base().get_instance_children();
                let children_with_envs = iter::repeat(template_children)
                    .take(source_len)
                    .enumerate()
                    .flat_map(|(i, children)| {
                        let property_i = Property::new(i);
                        let cp_source_expression = source_expression.clone();
                        let property_elem = Property::computed_with_name(
                            move || {
                                let source = cp_source_expression.get();
                                if let PaxValue::Range(start, _) = source {
                                    let start = isize::try_coerce(*start).unwrap();
                                    let elem = (start + i as isize).to_pax_value();
                                    elem
                                } else if let PaxValue::Vec(v) = source {
                                    v[i].clone()
                                } else {
                                    log::warn!("source is not a vec");
                                    Default::default()
                                }
                            },
                            &[source_expression.untyped()],
                            "repeat elem",
                        );

                        let mut scope: HashMap<String, Variable> = HashMap::new();
                        if let Some(i_symbol) = i_symbol.get() {
                            scope.insert(
                                i_symbol.clone(),
                                Variable::new_from_typed_property(property_i),
                            );
                        }
                        if let Some(elem_symbol) = elem_symbol.get() {
                            scope.insert(
                                elem_symbol,
                                Variable::new_from_typed_property(property_elem),
                            );
                        }

                        let new_env = cloned_expanded_node.stack.push(scope);
                        borrow!(children)
                            .clone()
                            .into_iter()
                            .zip(iter::repeat(new_env))
                    });
                let ret = cloned_expanded_node.generate_children(
                    children_with_envs,
                    &cloned_context,
                    &cloned_expanded_node.parent_frame,
                    is_mount,
                );
                ret
            },
            &deps,
            &format!("repeat_children (node id: {})", expanded_node.id.0),
        );
        expanded_node.children.replace_with(children);
    }
}