notes

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1. \* hl:data — NEED EVALUATION, the one implementation every realm edge uses.
3. A component's need is a member whose initializer calls a provider class
4. (SPEC.md §9.2); the graph publishes each as { key, provider, method, args,
5. project }. Evaluating one is: resolve the arguments against the caller's
6. context — a folded constant, a route group's member, or a `session`
7. field — call the provider method, and take the projected field. hl:web did
8. this per request and per push; hl:ipc does it per peer push. It lived in
9. hl:web until the second edge existed (2026-09-01), which is when "shared"
10. stopped being a word and became this plugin. *\
12. \* Every need of one component, against the provider instances of the calling
13. edge. One memo per evaluation: two needs fed by the same call cost ONE call. *\
14. runNeeds(
15. Hybrid needs \\ the graph's need list for the component
16. &providers \\ class name → provider instance (the edge module's)
17. &params \\ route groups; {} for a peer that matched no route
18. &sdata \\ the session bag; {} for a peer with no session
19. ) {
20. let out = {}
21. let memo = {}
22. for (need of needs) {
23. out[need.key] = runNeed(&need, &providers, &params, &sdata, &memo)
24. }
25. return out
26. }
28. \* One need: the value its MEMBER holds. `need.project` is the field taken off
29. the returned hybrid ("" = the member IS the return value). A provider read
30. answers for null arguments (the 074 contract), so an anonymous caller
31. evaluates the same needs and simply sees nothing of anyone. *\
32. runNeed(&need, &providers, &params, &sdata, &memo) {
33. let provider = providers[need.provider]
34. if (provider == null) {
35. return null
36. }
37. let args = []
38. for (a of need.args) {
39. if (a.group != null) {
40. args[] = params[a.group]
41. } else if (a.session != null) {
42. if (a.session.length == 0) {
43. args[] = sdata
44. } else {
45. args[] = sdata[a.session]
46. }
47. } else {
48. args[] = a.value
49. }
50. }
51. let ck = need.provider + "." + need.method + "(" + JSON.stringify(args) + ")"
52. // a call that ANSWERED null is simply not memoized — repeating it is correct
53. let result = memo[ck]
54. if (result == null) {
55. result = callProvider(&provider, need.method, &args)
56. memo[ck] = result
57. }
58. if (need.project.length == 0) {
59. return result
60. }
61. if (result == null) {
62. return null
63. }
64. return result[need.project]
65. }
67. // The provider call itself — the method name is DATA, so the call is computed.
68. callProvider(&provider, method, &args) {
69. if (args.length == 0) {
70. return provider[method]()
71. }
72. if (args.length == 1) {
73. return provider[method](args[0])
74. }
75. if (args.length == 2) {
76. return provider[method](args[0], args[1])
77. }
78. return provider[method](args[0], args[1], args[2])
79. }