feat(lsp): add context-aware completion ranking and document highlights

Adds context-aware completion ranking and document highlights for Tcl.
Adds completion_context to distinguish variables and commands.
Wires per-file completion snapshots and ranking into the flow.
Adds document_highlight provider support and tests for highlights.

- Context-aware ranking of completion items using per-file snapshots
- Document highlight provider wired into initialization and tests
- Tests for completion context, ranking, and document highlights

CHANGELOG.md

@@ -1,6 +1,8 @@
 ## Unreleased
 
 - Add incoming and outgoing call hierarchy for custom TCL procedures and MOM event handlers
+- Add document highlights for procedure and variable occurrences
+- Make completion context-aware and prioritize local, current-file, workspace, and built-in symbols
 - Integrate the NX Tcl Remote Debugger directly into NX Postprocessor Support
 - Add `nx-tcl` attach configurations and breakpoint support for TCL and DEF files
 - Support breakpoints, stepping, stack frames, variables, watches, evaluation, logpoints, hit conditions, and Tcl error stops

README.md

@@ -11,6 +11,8 @@ A comprehensive VS Code extension providing language support and remote debuggin
 - **Auto-completion** - Context-aware code completion for faster development
 - **Signature Help** - Shows parameters and documentation for custom and NX procedures
 - **Call Hierarchy** - Traces incoming and outgoing calls between custom TCL procedures and MOM event handlers
+- **Document Highlights** - Highlights all reads, writes, and calls of the symbol under the cursor
+- **Context-aware Completion** - Prioritizes local symbols and suggests variables or commands based on cursor context
 - **NX Tcl Remote Debugger** - Breakpoints, stepping, call stack, scopes, variables, watches, evaluation, logpoints, hit conditions, and Tcl error stops directly in a running NX Post process
 
 ## Supported File Types
@@ -98,6 +100,8 @@ Simply open any supported file type and enjoy:
 - Hover information
 - Signature help while entering procedure arguments
 - Incoming and outgoing call hierarchy for custom procedures and MOM event handlers
+- Document-wide highlights for procedure and variable occurrences
+- Context-aware completion with local symbols ranked before workspace and built-in symbols
 - Remote NX Tcl debugging with breakpoints and full stepping
 
 ## Contributing

server/src/lsp_server.py

@@ -44,6 +44,7 @@ from common.load_data import standard_items
 from lsp_tclserver import TclLanguageServer
 from pygls import uris
 from pygls.workspace.text_document import TextDocument
+from tools.completion_items import completion_context, ranked_completion_items
 from tools.folding_ranges import build_folding_ranges
 from tools.inlay_hint import (
     InlayHintGenerator,
@@ -54,6 +55,7 @@ from tools.navigation import (
     call_hierarchy_identity,
     call_hierarchy_items,
     definition_identities,
+    document_highlights,
     incoming_call_hierarchy,
     matching_occurrences,
     outgoing_call_hierarchy,
@@ -87,9 +89,9 @@ STATIC_COMPLETION_ITEMS = tuple(
     + standard_items.nx_procs
     + standard_items.nx_variables
 )
-STATIC_COMPLETION_KEYS = frozenset(
+STATIC_VARIABLE_ITEMS = {
-    (item.label, getattr(item, "kind", None)) for item in STATIC_COMPLETION_ITEMS
+    item.label: item for item in standard_items.nx_variables
-)
+}
 BUILTIN_INLAY_SIGNATURES = build_builtin_inlay_signatures(
     standard_items.json_data.get("MOM_procs", [])
 )
@@ -246,55 +248,63 @@ def document_diagnostic(params: lsp.DocumentDiagnosticParams):
     return lsp.FullDocumentDiagnosticReport(items=diagnostics, result_id=result_id)
 
 
-@LSP_SERVER.feature(lsp.TEXT_DOCUMENT_COMPLETION)
+@LSP_SERVER.feature(
+    lsp.TEXT_DOCUMENT_COMPLETION,
+    lsp.CompletionOptions(trigger_characters=["$"]),
+)
 def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
-    from tools.completion_items import BUILTIN_VAR_LABELS
-
     doc = LSP_SERVER.workspace.get_text_document(params.text_document.uri)
-
-    workspace_items = LSP_SERVER.completion_items_snapshot()
     tree = LSP_SERVER.get_tree(doc)
     globals_set, procs_locals, proc_ranges = LSP_SERVER.variable_index_for_document(
         doc, tree
     )
 
-    # Always include globals (excluding built-ins)
+    position = params.position
-    dynamic_items = []
+    local_names: set[str] = set()
-    for name in sorted(globals_set):
+    for proc_range in proc_ranges:
-        if name not in BUILTIN_VAR_LABELS:
+        end_line = proc_range.end_line or proc_range.start_line
-            dynamic_items.append(
+        if proc_range.start_line <= position.line <= end_line:
-                lsp.CompletionItem(label=name, kind=lsp.CompletionItemKind.Variable)
+            local_names.update(procs_locals.get(proc_range.name, set()))
+            break
+
+    candidates: list[tuple[int, lsp.CompletionItem]] = []
+    for name in sorted(local_names - globals_set):
+        candidates.append(
+            (
+                0,
+                lsp.CompletionItem(
+                    label=name,
+                    kind=lsp.CompletionItemKind.Variable,
+                    detail="Local variable",
+                ),
             )
+        )
 
-    # Include proc-local variables when cursor is inside that proc
+    for name in sorted(globals_set):
-    pos = params.position
+        item = STATIC_VARIABLE_ITEMS.get(name)
-    if pos is not None:
+        if item is None:
-        for pr in proc_ranges:
+            item = lsp.CompletionItem(
-            if pr.start_line <= pos.line <= (pr.end_line or pr.start_line):
+                label=name,
-                for name in sorted(procs_locals.get(pr.name, set())):
+                kind=lsp.CompletionItemKind.Variable,
-                    # Exclude built-ins and globals to avoid duplication
+                detail="Workspace variable",
-                    if name not in BUILTIN_VAR_LABELS and name not in globals_set:
+            )
-                        dynamic_items.append(
+        candidates.append(
-                            lsp.CompletionItem(
+            (
-                                label=name, kind=lsp.CompletionItemKind.Variable
+                100,
-                            )
+                item,
-                        )
+            )
-                break
+        )
 
-    # Merge with de-duplication. Each file keeps its complete index, so a proc
+    filepath = str(pathlib.Path(uris.to_fs_path(doc.uri)))
-    # declared in multiple files must only appear once in the completion list.
+    items_by_file = LSP_SERVER.completion_items_by_file_snapshot()
-    merged: list[lsp.CompletionItem] = list(STATIC_COMPLETION_ITEMS)
+    for item_path in sorted(items_by_file, key=lambda path: path.casefold()):
-    seen_items: set[tuple[str, lsp.CompletionItemKind | None]] = set(
+        priority = 100 if LSP_SERVER.paths_equal(item_path, filepath) else 200
-        STATIC_COMPLETION_KEYS
+        candidates.extend((priority, item) for item in items_by_file[item_path])
-    )
-    for it in (*workspace_items, *dynamic_items):
-        key = (it.label, getattr(it, "kind", None))
-        if key in seen_items:
-            continue
-        seen_items.add(key)
-        merged.append(it)
 
-    return lsp.CompletionList(is_incomplete=False, items=merged)
+    candidates.extend((300, item) for item in STATIC_COMPLETION_ITEMS)
+    context = completion_context(LSP_SERVER.get_lines(doc), position)
+    items = ranked_completion_items(candidates, context)
+    return lsp.CompletionList(is_incomplete=False, items=items)
 
 
 @LSP_SERVER.feature(
@@ -548,6 +558,20 @@ def references(params: lsp.ReferenceParams) -> list[lsp.Location]:
     return _sorted_locations(locations)
 
 
+@LSP_SERVER.feature(lsp.TEXT_DOCUMENT_DOCUMENT_HIGHLIGHT)
+def document_highlight(params: lsp.DocumentHighlightParams):
+    context = _navigation_context(params.text_document.uri, params.position)
+    if context is None:
+        return []
+
+    indexes, definitions, _, identity = context
+    filepath = str(pathlib.Path(uris.to_fs_path(params.text_document.uri)))
+    index = indexes.get(filepath)
+    if index is None:
+        return []
+    return document_highlights(index, identity, definitions)
+
+
 def _is_renamable(
     identity: SymbolIdentity,
     indexes,
@@ -744,6 +768,7 @@ def initialize(params: lsp.InitializeParams) -> lsp.InitializeResult:
                 legend=semantic_tokens_legend, full=True, range=False
             ),
             definition_provider=True,
+            document_highlight_provider=True,
             references_provider=True,
             rename_provider=lsp.RenameOptions(prepare_provider=True),
             workspace_symbol_provider=True,

server/src/lsp_tclserver.py

@@ -170,6 +170,15 @@ class TclLanguageServer(LanguageServer):
             self._workspace_completion_cache = (self._index_generation, items)
             return items
 
+    def completion_items_by_file_snapshot(
+        self,
+    ) -> dict[str, tuple[lsp.CompletionItem, ...]]:
+        """Return completion items grouped by source file for request ranking."""
+        with self._index_lock:
+            return {
+                path: tuple(items) for path, items in self.poco_completion.items()
+            }
+
     def custom_function_names_snapshot(self) -> frozenset[str]:
         """Return custom completion labels for semantic highlighting."""
         with self._index_lock:

server/src/tools/completion_items.py

@@ -1,3 +1,10 @@
+from __future__ import annotations
+
+import copy
+import re
+from collections.abc import Iterable, Sequence
+from enum import Enum
+
 import lsprotocol.types as lsp
 from common.load_data import standard_items
 from tclint.syntax_tree import BareWord, Command, List, Visitor
@@ -6,6 +13,86 @@ BUILTIN_VAR_LABELS = {ci.label for ci in standard_items.nx_variables}
 BUILTIN_PROC_LABELS = {ci.label for ci in standard_items.nx_procs}
 
 
+class CompletionContext(Enum):
+    VARIABLE = "variable"
+    COMMAND = "command"
+    GENERAL = "general"
+
+
+VARIABLE_KINDS = {
+    lsp.CompletionItemKind.Variable,
+    lsp.CompletionItemKind.Field,
+    lsp.CompletionItemKind.Constant,
+}
+COMMAND_KINDS = {
+    lsp.CompletionItemKind.Function,
+    lsp.CompletionItemKind.Method,
+    lsp.CompletionItemKind.Constructor,
+    lsp.CompletionItemKind.Keyword,
+}
+
+_VARIABLE_PREFIX_RE = re.compile(r"(?<!\\)\$(?:\{)?[A-Za-z0-9_:]*$")
+_COMMAND_PREFIX_RE = re.compile(r"(?:^|[;\[\{])\s*[^\s;\[\]\{\}]*$")
+
+
+def _codepoint_offset(line: str, utf16_offset: int) -> int:
+    """Translate an LSP UTF-16 character offset into a Python string offset."""
+    if utf16_offset <= 0:
+        return 0
+
+    units = 0
+    for offset, character in enumerate(line):
+        units += 2 if ord(character) > 0xFFFF else 1
+        if units >= utf16_offset:
+            return offset + 1
+    return len(line)
+
+
+def completion_context(
+    source_lines: Sequence[str], position: lsp.Position
+) -> CompletionContext:
+    if position.line < 0 or position.line >= len(source_lines):
+        return CompletionContext.GENERAL
+
+    line = source_lines[position.line]
+    prefix = line[: _codepoint_offset(line, position.character)]
+    if _VARIABLE_PREFIX_RE.search(prefix):
+        return CompletionContext.VARIABLE
+    if _COMMAND_PREFIX_RE.search(prefix):
+        return CompletionContext.COMMAND
+    return CompletionContext.GENERAL
+
+
+def _is_allowed(item: lsp.CompletionItem, context: CompletionContext) -> bool:
+    if context == CompletionContext.VARIABLE:
+        return item.kind in VARIABLE_KINDS
+    if context == CompletionContext.COMMAND:
+        return item.kind in COMMAND_KINDS
+    return True
+
+
+def ranked_completion_items(
+    candidates: Iterable[tuple[int, lsp.CompletionItem]],
+    context: CompletionContext,
+) -> list[lsp.CompletionItem]:
+    """Filter, de-duplicate, and rank completion candidates for one request."""
+    items = []
+    seen: set[tuple[str, lsp.CompletionItemKind | None]] = set()
+    for sequence, (priority, item) in enumerate(candidates):
+        if not _is_allowed(item, context):
+            continue
+
+        key = (item.label, item.kind)
+        if key in seen:
+            continue
+        seen.add(key)
+
+        ranked = copy.copy(item)
+        ranked.sort_text = f"{priority:03d}:{item.label.casefold()}:{sequence:06d}"
+        items.append(ranked)
+    return items
+
+
 class CompletionItems:
     def __init__(self):
         self._custom_functions: list[lsp.CompletionItem] = []
@@ -77,9 +164,17 @@ class CompletionCollector(Visitor):
         # Collect global variables declared with: global var1 var2 ...
         elif routine.contents == "global" and command.args:
             for arg in command.args:
-                if isinstance(arg, BareWord) and getattr(arg, "value", None):
+                if (
-                    if arg.value not in BUILTIN_VAR_LABELS:
+                    isinstance(arg, BareWord)
-                        self._append_unique(lsp.CompletionItem(label=arg.value, kind=lsp.CompletionItemKind.Variable))
+                    and getattr(arg, "value", None)
+                    and arg.value not in BUILTIN_VAR_LABELS
+                ):
+                    self._append_unique(
+                        lsp.CompletionItem(
+                            label=arg.value,
+                            kind=lsp.CompletionItemKind.Variable,
+                        )
+                    )
 
         # Collect variables set with explicit global namespace: set ::var_name ...
         elif routine.contents == "set" and command.args:

server/src/tools/navigation.py

@@ -522,6 +522,37 @@ def matching_occurrences(
     return matches
 
 
+def document_highlights(
+    index: FileSymbolIndex,
+    identity: SymbolIdentity,
+    definitions: set[SymbolIdentity],
+) -> list[lsp.DocumentHighlight]:
+    """Return all occurrences of one symbol in the active document."""
+    highlights = []
+    for occurrence in index.occurrences:
+        if resolve_identity(occurrence, definitions) != identity:
+            continue
+
+        kind = lsp.DocumentHighlightKind.Text
+        if identity.kind == "variable":
+            kind = (
+                lsp.DocumentHighlightKind.Write
+                if occurrence.is_definition
+                else lsp.DocumentHighlightKind.Read
+            )
+        highlights.append(lsp.DocumentHighlight(range=occurrence.range, kind=kind))
+
+    return sorted(
+        highlights,
+        key=lambda highlight: (
+            highlight.range.start.line,
+            highlight.range.start.character,
+            highlight.range.end.line,
+            highlight.range.end.character,
+        ),
+    )
+
+
 def workspace_symbols(
     indexes: dict[str, FileSymbolIndex], query: str
 ) -> list[lsp.SymbolInformation]:

server/tests/python_tests/test_completion_context.py

@@ -0,0 +1,152 @@
+import sys
+from pathlib import Path
+
+THIS_DIR = Path(__file__).parent
+SRC_DIR = THIS_DIR.parent.parent / "src"
+if str(SRC_DIR) not in sys.path:
+    sys.path.insert(0, str(SRC_DIR))
+
+import lsp_server
+import lsprotocol.types as lsp  # type: ignore
+from common.load_data import standard_items
+from lsp_tclserver import TclLanguageServer
+from pygls.workspace import Workspace
+from pygls.workspace.text_document import TextDocument
+from tools.completion_items import (
+    COMMAND_KINDS,
+    VARIABLE_KINDS,
+    CompletionContext,
+    completion_context,
+)
+
+
+def _position_after(source: str, token: str, occurrence: int = 0) -> lsp.Position:
+    offset = -1
+    for _ in range(occurrence + 1):
+        offset = source.index(token, offset + 1)
+    offset += len(token)
+    before = source[:offset]
+    return lsp.Position(
+        line=before.count("\n"),
+        character=offset - (before.rfind("\n") + 1),
+    )
+
+
+def _document(path: Path, source: str) -> TextDocument:
+    return TextDocument(
+        uri=path.as_uri(),
+        source=source,
+        version=1,
+        language_id="tcl",
+    )
+
+
+def _completion_server(
+    tmp_path: Path, monkeypatch
+) -> tuple[TclLanguageServer, TextDocument, str]:
+    declared_builtin = standard_items.nx_variables[0].label
+    current_source = (
+        "set globalValue 1\n"
+        "proc localProc {} { return }\n"
+        "proc caller {argument} {\n"
+        f"    global {declared_builtin}\n"
+        "    set localValue 2\n"
+        "    puts $local\n"
+        "    localP\n"
+        "}\n"
+    )
+    workspace_source = """set ::workspaceValue 1
+proc workspaceProc {} { return }
+"""
+    current = _document(tmp_path / "current.tcl", current_source)
+    workspace = _document(tmp_path / "workspace.tcl", workspace_source)
+    server = TclLanguageServer(name="completion-test", version="1", max_workers=1)
+    server.protocol._workspace = Workspace(  # pylint: disable=protected-access
+        root_uri=None,
+        sync_kind=lsp.TextDocumentSyncKind.Incremental,
+        workspace_folders=[],
+        position_encoding=lsp.PositionEncodingKind.Utf16,
+    )
+    server.workspace.put_text_document(
+        lsp.TextDocumentItem(
+            uri=current.uri,
+            language_id="tcl",
+            version=1,
+            text=current_source,
+        )
+    )
+    assert server.update_poco_completion_for_file(current)
+    assert server.update_poco_completion_for_file(workspace)
+    monkeypatch.setattr(lsp_server, "LSP_SERVER", server)
+    return server, current, current_source
+
+
+def _complete(document: TextDocument, position: lsp.Position):
+    return lsp_server.on_completion(
+        lsp.CompletionParams(
+            text_document=lsp.TextDocumentIdentifier(uri=document.uri),
+            position=position,
+        )
+    ).items
+
+
+def test_variable_completion_filters_and_ranks_candidates(tmp_path: Path, monkeypatch):
+    _, current, source = _completion_server(tmp_path, monkeypatch)
+    items = _complete(current, _position_after(source, "$local"))
+    by_label = {item.label: item for item in items}
+
+    assert items
+    assert all(item.kind in VARIABLE_KINDS for item in items)
+    assert "localValue" in by_label
+    assert "globalValue" in by_label
+    assert "workspaceValue" in by_label
+    assert "localProc" not in by_label
+    assert "workspaceProc" not in by_label
+    assert "puts" not in by_label
+
+    declared_builtin = standard_items.nx_variables[0]
+    other_builtin = standard_items.nx_variables[1]
+    assert declared_builtin.label in by_label
+    assert other_builtin.label in by_label
+    assert by_label[declared_builtin.label].documentation == (
+        declared_builtin.documentation
+    )
+    assert by_label["localValue"].sort_text.startswith("000:")
+    assert by_label["globalValue"].sort_text.startswith("100:")
+    assert by_label["workspaceValue"].sort_text.startswith("200:")
+    assert by_label[declared_builtin.label].sort_text.startswith("100:")
+    assert by_label[other_builtin.label].sort_text.startswith("300:")
+
+
+def test_command_completion_filters_and_ranks_candidates(tmp_path: Path, monkeypatch):
+    _, current, source = _completion_server(tmp_path, monkeypatch)
+    items = _complete(current, _position_after(source, "localP", occurrence=1))
+    by_label = {item.label: item for item in items}
+
+    assert items
+    assert all(item.kind in COMMAND_KINDS for item in items)
+    assert "localProc" in by_label
+    assert "workspaceProc" in by_label
+    assert "MOM_abort" in by_label
+    assert "puts" in by_label
+    assert "localValue" not in by_label
+    assert "globalValue" not in by_label
+    assert "workspaceValue" not in by_label
+    assert by_label["localProc"].sort_text.startswith("100:")
+    assert by_label["workspaceProc"].sort_text.startswith("200:")
+    assert by_label["MOM_abort"].sort_text.startswith("300:")
+
+
+def test_completion_context_handles_nested_commands_and_utf16():
+    assert (
+        completion_context(["set result [work"], lsp.Position(line=0, character=16))
+        == CompletionContext.COMMAND
+    )
+    assert (
+        completion_context(["😀 puts $value"], lsp.Position(line=0, character=14))
+        == CompletionContext.VARIABLE
+    )
+    assert (
+        completion_context(["puts value"], lsp.Position(line=0, character=10))
+        == CompletionContext.GENERAL
+    )

server/tests/python_tests/test_navigation.py

@@ -401,3 +401,62 @@ def test_call_hierarchy_item_uses_whole_proc_range(tmp_path: Path):
     assert items[0].selection_range.start == lsp.Position(line=0, character=5)
     assert items[0].range.start == lsp.Position(line=0, character=0)
     assert items[0].range.end.line == 2
+
+
+def test_document_highlight_marks_local_reads_and_writes(tmp_path: Path, monkeypatch):
+    source = """proc first {} {
+    set value 1
+    puts $value
+    incr value
+}
+proc second {} {
+    set value 2
+    puts $value
+}
+"""
+    document = _document(tmp_path / "highlights.tcl", source)
+    server = TclLanguageServer(name="highlight-test", version="1", max_workers=1)
+    assert server.update_poco_completion_for_file(document)
+    monkeypatch.setattr(lsp_server, "LSP_SERVER", server)
+    position = _position(source, "$value")
+
+    highlights = lsp_server.document_highlight(
+        lsp.DocumentHighlightParams(
+            text_document=lsp.TextDocumentIdentifier(uri=document.uri),
+            position=lsp.Position(position.line, position.character + 1),
+        )
+    )
+
+    assert len(highlights) == 3
+    assert [highlight.kind for highlight in highlights] == [
+        lsp.DocumentHighlightKind.Write,
+        lsp.DocumentHighlightKind.Read,
+        lsp.DocumentHighlightKind.Write,
+    ]
+    assert all(_range_text(source, highlight.range) == "value" for highlight in highlights)
+
+
+def test_document_highlight_marks_proc_definition_and_calls(tmp_path: Path, monkeypatch):
+    source = """proc target {} { return }
+proc caller {} {
+    target
+    target
+}
+"""
+    document = _document(tmp_path / "proc_highlights.tcl", source)
+    server = TclLanguageServer(name="highlight-test", version="1", max_workers=1)
+    assert server.update_poco_completion_for_file(document)
+    monkeypatch.setattr(lsp_server, "LSP_SERVER", server)
+
+    highlights = lsp_server.document_highlight(
+        lsp.DocumentHighlightParams(
+            text_document=lsp.TextDocumentIdentifier(uri=document.uri),
+            position=_position(source, "target"),
+        )
+    )
+
+    assert len(highlights) == 3
+    assert all(
+        highlight.kind == lsp.DocumentHighlightKind.Text
+        for highlight in highlights
+    )