src/syntax/process/node_state_stores.ghul

1		namespace Syntax.Process is
2		use Collections;
3
4		// Contract for a pass-owned store of per-node derived state.
5		//
6		// A pass that computes state about tree nodes keeps it in a store it
7		// owns, keyed by the node, rather than in fields on the node itself.
8		// The tree then carries only what the source says; each store's
9		// contents have a single producer, and the state's lifetime is
10		// managed explicitly (see STATE_STORE_REGISTRY) instead of riding
11		// along with the tree object's lifetime.
12		trait NodeStateStore is
13		name: string;
14		entry_count: int;
15
16		// Forget everything recorded against nodes of one file. Called
17		// when a file's tree is replaced (re-parse), so entries keyed by
18		// the abandoned tree's nodes cannot accumulate.
19		drop_file(file_name: string);
20
21		clear_all();
22		si
23
24		// Every NodeStateStore registers here. The registry is the one place
25		// that lists all per-node derived state and gives file replacement
26		// and full-rebuild paths a single call to evict it.
27		class STATE_STORE_REGISTRY is
28		_stores: MutableList[NodeStateStore];
29
30		init() is
31		_stores = LIST[NodeStateStore]();
32		si
33
34		register(store: NodeStateStore) is
35		_stores.add(store);
36		si
37
38		drop_file(file_name: string) is
39		for store in _stores do
40		store.drop_file(file_name);
41		od
42		si
43
44		clear_all() is
45		for store in _stores do
46		store.clear_all();
47		od
48		si
49
50		describe() -> string is
51		let result = System.Text.StringBuilder();
52
53		for store in _stores do
54		result
55		.append(store.name)
56		.append(": ")
57		.append(store.entry_count)
58		.append(" entries\n");
59		od
60
61		return result.to_string();
62		si
63		si
64		si