feat(lsp): support completion item resolve to show .def previews

Enable completion item resolution so selecting a completion can populate
documentation with a preview of the corresponding .def declaration.

- Turn on resolve_provider in the completion options.
- Implement on_completion_resolve to attach Markdown documentation
  computed by def_hover_markdown when the completion item's data
  contains a ("def" -> [kind, name]) payload.
- Include that "def" payload when generating def-related completion items.
- Add tests that verify block-template and address-list items resolve to
  Markdown previews.

Before: def-related completion items had no documentation on resolve.
After: selecting such items will return a Markdown preview of the .def entry.

server/src/lsp_server.py

@@ -287,7 +287,7 @@ def document_diagnostic(params: lsp.DocumentDiagnosticParams):
 
 @LSP_SERVER.feature(
     lsp.TEXT_DOCUMENT_COMPLETION,
-    lsp.CompletionOptions(trigger_characters=["$", " ", "-", "(", ","]),
+    lsp.CompletionOptions(trigger_characters=["$", " ", "-", "(", ","], resolve_provider=True),
 )
 def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
     result = _on_completion(params)
@@ -300,6 +300,17 @@ def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
     return result
 
 
+@LSP_SERVER.feature(lsp.COMPLETION_ITEM_RESOLVE)
+def on_completion_resolve(item: lsp.CompletionItem) -> lsp.CompletionItem:
+    """Show the .def declaration of a selected block template/address, as on hover."""
+    target = item.data.get("def") if isinstance(item.data, dict) else None
+    if item.documentation is None and isinstance(target, list) and len(target) == 2:
+        markdown = def_hover_markdown(LSP_SERVER.def_documents_snapshot(), tuple(target))
+        if markdown:
+            item.documentation = lsp.MarkupContent(kind=lsp.MarkupKind.Markdown, value=markdown)
+    return item
+
+
 # Keywords that expand to all loaded .def names: keyword -> (items, description).
 SYMBOL_LIST_KEYWORDS = {
     "BLOCK_LIST": (lambda: LSP_SERVER.block_template_items(), "block templates"),

server/src/lsp_tclserver.py

@@ -290,6 +290,7 @@ class TclLanguageServer(LanguageServer):
                 label=name,
                 kind=item_kind,
                 detail=f"{description} ({pathlib.Path(path).name})",
+                data={"def": [kind, name]},
             )
             for path, document in self.def_documents_snapshot().items()
             for name in document.names(kind)

server/tests/python_tests/test_def_symbols.py

@@ -227,6 +227,25 @@ def test_block_list_shows_all_templates_quoted(tmp_path, monkeypatch):
     assert all(item.filter_text.startswith("BLOCK_LIST") for item in items)
 
 
+def test_block_list_item_resolves_to_template_preview(tmp_path, monkeypatch):
+    server, _ = _project(tmp_path, monkeypatch)
+    items = _complete(server, tmp_path, "set a 1\n    BLOCK_LIST")
+    assert all(item.documentation is None for item in items)
+    item = next(item for item in items if item.label == "steady_rest")
+    resolved = lsp_server.on_completion_resolve(item)
+    assert resolved.documentation.kind == lsp.MarkupKind.Markdown
+    assert "**Block template** `steady_rest`" in resolved.documentation.value
+    assert "Text[M60]" in resolved.documentation.value
+
+
+def test_address_list_item_resolves_to_address_table(tmp_path, monkeypatch):
+    server, _ = _project(tmp_path, monkeypatch)
+    items = _complete(server, tmp_path, "set a 1\n    ADDR_LIST")
+    item = next(item for item in items if item.label == "SPOS")
+    resolved = lsp_server.on_completion_resolve(item)
+    assert "| Format | `Coordinate` |" in resolved.documentation.value
+
+
 def test_block_list_ignores_variables_and_other_words(tmp_path, monkeypatch):
     server, _ = _project(tmp_path, monkeypatch)
     for source in ("set x $BLOCK_LIST", "set x MY_BLOCK_LIST", "set x steady"):