legato 0.0.10

Legato is a WIP audiograph and DSL for quickly developing audio applications
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

use crate::dsl::{ir::*, pipeline::GraphPass};
use indexmap::IndexMap;
use std::collections::HashMap;

/// This pass expands all [`IRMacros`] into the interior nodes,
/// wires the new interior connections, then handles connections
/// in and out to the macro instance.
#[derive(Default)]
pub struct MacroExpansionPass;

const MAXIMUM_DEPTH: u8 = 16;

impl GraphPass for MacroExpansionPass {
    fn name(&self) -> &'static str {
        "MacroExpansionPass"
    }
    /// Expand macros while they still exist.
    fn run(&self, mut graph: IRGraph) -> IRGraph {
        let mut depth = 0u8;
        while graph.has_unresolved_macros() {
            assert!(
                depth < MAXIMUM_DEPTH,
                "MacroExpansionPass exceeded maximum depth — possible cycle in macro definitions"
            );
            let macro_ids: Vec<NodeId> = graph.macro_nodes().map(|n| n.id).collect();
            for id in macro_ids {
                self.expand_macro(&mut graph, id);
            }
            depth += 1;
        }
        graph
    }
}

impl MacroExpansionPass {
    fn expand_macro(&self, graph: &mut IRGraph, node_id: NodeId) {
        let node = graph.get_node(node_id).unwrap().clone();

        let ir_macro = graph
            .macro_registry
            .get(&node.node_type)
            .cloned()
            .unwrap_or_else(|| panic!("Macro '{}' not found in registry", node.node_type));

        let mut resolved_params = ir_macro.default_params.clone().unwrap_or_default();
        for (k, v) in &node.params {
            resolved_params.insert(k.clone(), v.clone());
        }

        let incoming: Vec<IREdge> = graph.incoming_edges(node_id).cloned().collect();
        let outgoing: Vec<IREdge> = graph.outgoing_edges(node_id).cloned().collect();
        graph.remove_node(node_id);

        // Expand n=count instances, each with a distinct alias prefix.
        let mut new_sinks: Vec<NodeId> = Vec::with_capacity(node.count as usize);

        for i in 0..node.count as usize {
            let instance_alias = if node.count == 1 {
                node.alias.clone()
            } else {
                format!("{}.{}", node.alias, i)
            };

            let id_map = self.clone_body_into(graph, &ir_macro, &instance_alias, &resolved_params);
            let new_sink = id_map[&ir_macro.sink];
            new_sinks.push(new_sink);

            let remapped_virtual: IndexMap<String, Vec<(NodeId, NodeSelector, Port)>> = ir_macro
                .virtual_input_map
                .iter()
                .map(|(name, targets)| {
                    let remapped = targets
                        .iter()
                        .map(|(id, sel, port)| (id_map[id], sel.clone(), port.clone()))
                        .collect();
                    (name.clone(), remapped)
                })
                .collect();

            // Rewire incoming edges into each instance.
            for edge in &incoming {
                // Resolve to a specific source port depending on the type
                let resolved_source_port = match &edge.source_port {
                    Port::Stride { start, stride, .. } => Port::Index(start + i * stride),
                    Port::Slice(start, _) => Port::Index(start + i),
                    other => other.clone(),
                };

                // We also want to change behavior depending on the src_count.
                // We want the following invariants:
                // n:n arity -> zip
                // n:1 arity -> fan in
                // 1:n arity -> fan out
                // n:m -> panic
                let resolved_source_selector = {
                    let src_count = graph.get_node(edge.source).map(|n| n.count).unwrap_or(1);
                    match (src_count, node.count) {
                        (n, m) if n == m && n > 1 => NodeSelector::Index(i), // zip, just use node count i
                        (n, m) if n != m && n > 1 && m > 1 => {
                            panic!("Cannot match node selection arity {}:{}", n, m)
                        }
                        _ => edge.source_selector.clone(), // 1:1, 1:N broadcast, N:1, fan-in,  preserve original
                    }
                };

                let targets: Vec<(NodeId, NodeSelector, Port)> = match &edge.sink_port {
                    Port::Named(name) => remapped_virtual.get(name).cloned().unwrap_or_else(|| {
                        vec![(new_sink, NodeSelector::Single, edge.sink_port.clone())]
                    }),
                    Port::Index(i) => remapped_virtual
                        .get_index(*i)
                        .map(|(_, v)| v.clone())
                        .unwrap_or_else(|| {
                            vec![(new_sink, NodeSelector::Single, edge.sink_port.clone())]
                        }),
                    Port::None => remapped_virtual
                        .get_index(0)
                        .map(|(_, v)| v.clone())
                        .unwrap_or_else(|| vec![(new_sink, NodeSelector::Single, Port::None)]),
                    Port::Slice(..) | Port::Stride { .. } => panic!(
                        "Slice/Stride not supported on virtual ports (macro '{}')",
                        node.node_type
                    ),
                };
                for (target_id, target_selector, target_port) in targets {
                    graph.connect_multi(
                        edge.source,
                        resolved_source_selector.clone(),
                        resolved_source_port.clone(),
                        target_id,
                        target_selector,
                        target_port,
                    );
                }
            }
        }

        // Rewire outgoing edges from the last instance
        for edge in &outgoing {
            let srcs = edge.source_selector.select(&new_sinks).to_vec();
            for (i, &src) in srcs.iter().enumerate() {
                let resolved_sink_port = match &edge.sink_port {
                    Port::Slice(start, _) => Port::Index(start + i),
                    Port::Stride { start, stride, .. } => Port::Index(start + i * stride),
                    other => other.clone(),
                };
                graph.connect_multi(
                    src,
                    NodeSelector::Single,
                    edge.source_port.clone(),
                    edge.sink,
                    edge.sink_selector.clone(),
                    resolved_sink_port,
                );
            }
        }

        if graph.sink == Some(node_id) {
            graph.sink = new_sinks.last().copied();
        }
        if graph.source == Some(node_id) {
            graph.source = new_sinks.first().copied();
        }
    }

    /// Clone an IRMacro's body into [`IRGraph`], prefixing all aliases.
    fn clone_body_into(
        &self,
        graph: &mut IRGraph,
        ir_macro: &IRMacro,
        instance_alias: &str,
        resolved_params: &Object,
    ) -> HashMap<NodeId, NodeId> {
        let mut id_map: HashMap<NodeId, NodeId> = HashMap::new();

        // A this point, everything should be a leaf!
        for node in ir_macro.body.nodes() {
            let fqn = format!("{}.{}", instance_alias, node.alias);

            let mut params = node.params.clone();
            Self::substitute_templates(&mut params, resolved_params);

            let new_id = graph.add_node(
                node.kind.clone(),
                node.namespace.clone(),
                node.node_type.clone(),
                fqn,
                params,
                node.pipes.clone(),
                node.count,
            );
            id_map.insert(node.id, new_id);
        }

        // Clone edges
        for edge in ir_macro.body.edges() {
            graph.reconnect(id_map[&edge.source], id_map[&edge.sink], edge);
        }

        id_map
    }

    fn substitute_templates(params: &mut Object, lookup: &Object) {
        for val in params.values_mut() {
            if let Value::Template(tpl) = val {
                let key = tpl.trim_start_matches('$');
                if let Some(replacement) = lookup.get(key) {
                    *val = replacement.clone();
                }
            }
        }
    }
}