server/src/lsp_server.py

@@ -47,6 +47,7 @@ from common.load_data import standard_items
 from lsp_tclserver import TclLanguageServer
 from tools.completion_items import (
     CompletionContext,
+    array_element_completions,
     completion_context,
     ranked_completion_items,
 )
@@ -271,12 +272,18 @@ def document_diagnostic(params: lsp.DocumentDiagnosticParams):
 
 @LSP_SERVER.feature(
     lsp.TEXT_DOCUMENT_COMPLETION,
-    lsp.CompletionOptions(trigger_characters=["$", " ", "-"]),
+    lsp.CompletionOptions(trigger_characters=["$", " ", "-", "(", ","]),
 )
 def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
     doc = LSP_SERVER.workspace.get_text_document(params.text_document.uri)
     position = params.position
     source_lines = LSP_SERVER.get_lines(doc)
+    array_items = array_element_completions(
+        source_lines, position, LSP_SERVER.navigation_snapshot().values(),
+        str(pathlib.Path(uris.to_fs_path(doc.uri))),
+    )
+    if array_items is not None:
+        return lsp.CompletionList(is_incomplete=False, items=array_items)
     context = completion_context(source_lines, position)
 
     # Variable completion wins inside command arguments. Otherwise prefer the
@@ -323,7 +330,7 @@ def on_completion(params: lsp.CompletionParams) -> lsp.CompletionList:
         and params.context is not None
         and params.context.trigger_kind
         == lsp.CompletionTriggerKind.TriggerCharacter
-        and params.context.trigger_character in {" ", "-"}
+        and params.context.trigger_character in {" ", "-", "(", ","}
     ):
         return lsp.CompletionList(is_incomplete=False, items=[])
 

server/src/tools/completion_items.py

@@ -9,7 +9,13 @@ import lsprotocol.types as lsp
 from tclint.syntax_tree import BareWord, Command, List, Visitor
 
 from common.load_data import standard_items
-from tools.tcl_command_completion import line_prefix_at_position
+from tools.navigation import FileSymbolIndex
+from tools.variable_names import variable_name
+from tools.tcl_command_completion import (
+    DynamicCompletionKind,
+    line_prefix_at_position,
+    tcl_argument_completion,
+)
 
 BUILTIN_VAR_LABELS = {ci.label for ci in standard_items.nx_variables}
 BUILTIN_PROC_LABELS = {ci.label for ci in standard_items.nx_procs}
@@ -36,6 +42,94 @@ COMMAND_KINDS = {
 
 _VARIABLE_PREFIX_RE = re.compile(r"(?<!\\)\$(?:\{)?[A-Za-z0-9_:]*$")
 _COMMAND_PREFIX_RE = re.compile(r"(?:^|[;\[\{])\s*[^\s;\[\]\{\}]*$")
+_ARRAY_PREFIX_RE = re.compile(
+    r"(?P<name>(?:::)?[A-Za-z_][A-Za-z0-9_:]*)\((?P<key>[^()\n]*)$"
+)
+
+
+def array_element_completions(
+    source_lines: Sequence[str],
+    position: lsp.Position,
+    indexes: Iterable[FileSymbolIndex],
+    current_path: str,
+) -> list[lsp.CompletionItem] | None:
+    """Complete literal array keys, replacing only the text inside parentheses."""
+    prefix = line_prefix_at_position(source_lines, position)
+    if prefix is None:
+        return None
+    match = _ARRAY_PREFIX_RE.search(prefix)
+    if match is None:
+        return None
+    before = prefix[:match.start()]
+    if not before.endswith("$"):
+        argument = tcl_argument_completion(source_lines, position)
+        if argument is None or argument.dynamic_kind != DynamicCompletionKind.VARIABLE:
+            return None
+    name, key_prefix = match.group("name", "key")
+    part_index = key_prefix.count(",")
+    key_prefix = key_prefix.rsplit(",", 1)[-1]
+    if any(char in key_prefix for char in "$[]{}\\"):
+        return None
+    indexes = list(indexes)
+    local_scope = None
+    for index in indexes:
+        if index.path != current_path:
+            continue
+        for occurrence in index.occurrences:
+            span = occurrence.declaration_range
+            if (
+                occurrence.identity.kind == "proc"
+                and occurrence.is_definition
+                and span is not None
+                and span.start.line <= position.line <= span.end.line
+            ):
+                local_scope = f"{index.path}::proc::{occurrence.identity.name}"
+    keys: dict[str, set[tuple[str | None, ...]]] = {}
+    for index in indexes:
+        for occurrence in index.occurrences:
+            parts = occurrence.array_parts
+            key = parts[part_index] if part_index < len(parts) else None
+            if (
+                key
+                and (
+                    occurrence.identity.scope is None
+                    or occurrence.identity.scope == local_scope
+                )
+                and key.startswith(key_prefix)
+                and not any(char in key for char in "$[]\\")
+                and occurrence.identity.name.removeprefix("::") == name.removeprefix("::")
+            ):
+                keys.setdefault(key, set()).add(occurrence.array_template_parts[part_index + 1:])
+    line = source_lines[position.line]
+    suffix = line[len(prefix):]
+    remaining = re.match(r"[^(),\s$\[\]{}]*", suffix).group()
+    has_close = suffix[len(remaining):].startswith((")", ","))
+    start = position.character - len(key_prefix.encode("utf-16-le")) // 2
+    end = position.character + len(remaining.encode("utf-16-le")) // 2
+    items = []
+    for key in sorted(keys):
+        new_text = key
+        # Fill missing index components only; keep an existing comma and suffix.
+        if not suffix[len(remaining):].startswith(","):
+            tails = sorted(keys[key], key=lambda tail: (len(tail), repr(tail)))
+            tail = tails[0]
+            if all(part is not None for part in tail) and any("$" in part for part in tail):
+                new_text = ",".join([key, *tail])
+        new_text += "" if has_close else ")"
+        items.append(lsp.CompletionItem(
+            label=key,
+            kind=lsp.CompletionItemKind.Field,
+            detail=f"{name}({key})",
+            insert_text_format=lsp.InsertTextFormat.PlainText,
+            text_edit=lsp.TextEdit(
+                range=lsp.Range(
+                    start=lsp.Position(line=position.line, character=start),
+                    end=lsp.Position(line=position.line, character=end),
+                ),
+                new_text=new_text,
+            ),
+        ))
+    return items
 
 
 def completion_context(
@@ -167,8 +261,8 @@ class CompletionCollector(Visitor):
         # Collect variables set with explicit global namespace: set ::var_name ...
         elif routine.contents == "set" and command.args:
             first = command.args[0]
-            if isinstance(first, BareWord) and getattr(first, "value", None):
-                var_name = first.value
+            var_name = variable_name(first)
+            if var_name:
                 if var_name.startswith("::"):
                     base_name = var_name.split("(", 1)[0]
                     clean_name = base_name[2:]  # remove leading '::' for completion display

server/src/tools/navigation.py

@@ -4,7 +4,8 @@ from dataclasses import dataclass
 from pathlib import Path
 
 import lsprotocol.types as lsp
-from tclint.syntax_tree import Command, List, Node, Script, VarSub
+from tclint.syntax_tree import Command, List, Node, QuotedWord, Script, VarSub
+from tools.variable_names import array_key_parts, variable_name
 
 ROOT_NAMESPACE = "::"
 
@@ -27,6 +28,9 @@ class SymbolOccurrence:
     fallback_identity: SymbolIdentity | None = None
     caller: SymbolIdentity | None = None
     declaration_range: lsp.Range | None = None
+    array_element: str | None = None
+    array_parts: tuple[str | None, ...] = ()
+    array_template_parts: tuple[str | None, ...] = ()
 
 
 @dataclass(frozen=True)
@@ -96,6 +100,8 @@ def _name_range(node: Node, raw_name: str, *, variable_sub: bool = False) -> lsp
         column += 2 if getattr(node, "braced", False) else 1
     else:
         position = getattr(node, "contents_pos", None) or node.pos
+        if isinstance(node, QuotedWord) and node.contents is None and node.children:
+            position = node.children[0].pos
         line, column = position
 
     normalized = _without_array_index(raw_name)
@@ -312,6 +318,13 @@ def build_file_symbol_index(
                 is_definition=is_definition,
                 symbol_kind=lsp.SymbolKind.Variable,
                 container_name=_container_name(symbol_identity),
+                array_element=(
+                    raw_name.split("(", 1)[1][:-1]
+                    if "(" in raw_name and raw_name.endswith(")")
+                    else None
+                ),
+                array_parts=array_key_parts(node),
+                array_template_parts=array_key_parts(node, preserve_variables=True),
             )
         )
 
@@ -444,7 +457,7 @@ def build_file_symbol_index(
         for node, is_definition in _variable_command_nodes(command):
             if id(node) in declaration_ids:
                 continue
-            raw_name = _static_contents(node)
+            raw_name = variable_name(node)
             if raw_name:
                 add_variable(
                     node,

server/src/tools/semantic_tokens.py

@@ -5,6 +5,7 @@ import attrs
 from common.load_data import standard_items
 from tclint.commands.plugins import PluginManager
 from tclint.syntax_tree import BareWord, Command, QuotedWord, Visitor
+from tools.variable_names import variable_name
 
 # Constructing a PluginManager scans entry points, and get_commands() rebuilds
 # the builtin command set on every call. Semantic tokens are requested often, so
@@ -159,6 +160,11 @@ class _Highlighter(Visitor):
         if routine.contents == "set" and command.args:
             first_arg = command.args[0]
             token_info = self._get_token_info(first_arg)
+            if first_arg.contents is None:
+                name = variable_name(first_arg)
+                if name:
+                    line, col = first_arg.children[0].pos
+                    token_info = ((line - 1, col - 1), len(name))
             if token_info:
                 (line, col), length = token_info
                 self._append_token((line, col), length, "variable", [TokenModifier.declaration])

server/src/tools/variable_index.py

@@ -4,6 +4,7 @@ from dataclasses import dataclass
 
 from tclint.syntax_tree import Command, Node, Script
 from tclint.syntax_tree import List as TclList
+from tools.variable_names import variable_name
 
 
 @dataclass
@@ -81,7 +82,7 @@ def build_variable_index(
                 return
 
             if routine == "set" and node.args:
-                raw_name = getattr(node.args[0], "contents", None)
+                raw_name = variable_name(node.args[0])
                 base = _normalize_var_name(raw_name)
                 if base is not None:
                     if raw_name and raw_name.startswith("::"):

server/src/tools/variable_names.py

@@ -0,0 +1,44 @@
+"""Extract statically known variable names without evaluating Tcl substitutions."""
+
+from tclint.syntax_tree import BareWord, CompoundBareWord, Node, QuotedWord, VarSub
+
+
+def variable_name(node: Node) -> str | None:
+    contents = node.contents
+    if isinstance(contents, str):
+        return contents
+    if isinstance(node, (CompoundBareWord, QuotedWord)) and node.children:
+        first = node.children[0]
+        last = node.children[-1]
+        if (
+            isinstance(first, BareWord)
+            and isinstance(last, BareWord)
+            and "(" in first.value
+            and last.value.endswith(")")
+        ):
+            # Substitutions in an array index do not change the array's name.
+            return first.value.split("(", 1)[0] or None
+    return None
+
+
+def array_key_parts(node: Node, *, preserve_variables: bool = False) -> tuple[str | None, ...]:
+    """Keep comma-separated literal index components; substitutions are unknown."""
+    contents = node.contents
+    if not isinstance(contents, str):
+        if not isinstance(node, (CompoundBareWord, QuotedWord)) or not variable_name(node):
+            return ()
+        chunks = []
+        for child in node.children:
+            if isinstance(child, BareWord):
+                chunks.append(child.value)
+            elif preserve_variables and isinstance(child, VarSub) and not child.children:
+                chunks.append("${" + child.value + "}" if child.braced else "$" + child.value)
+            else:
+                chunks.append("\0")
+        contents = "".join(chunks)
+    if "(" not in contents or not contents.endswith(")"):
+        return ()
+    return tuple(
+        part if part and not any(char in part for char in ("\0[]\\" if preserve_variables else "\0$[]\\")) else None
+        for part in contents.split("(", 1)[1][:-1].split(",")
+    )

server/tests/python_tests/test_completion_context.py

@@ -103,6 +103,133 @@ def _argument_completion_labels(source: str) -> set[str] | None:
     return {item.label for item in completion.items}
 
 
+def test_array_keys_complete_in_set_and_substitution(tmp_path: Path, monkeypatch):
+    server, _, _ = _completion_server(tmp_path, monkeypatch)
+    workspace = _document(
+        tmp_path / "arrays.tcl",
+        "set ::lib_flag(enabled) 1\nset ::lib_flag(external) 1\n",
+    )
+    assert server.update_poco_completion_for_file(workspace)
+    source = (
+        "set lib_flag(enabled) 0\n"
+        "set lib_flag(empty) 1\n"
+        "set other(wrong) 1\n"
+        "proc hidden {} { set lib_flag(private) 1 }\n"
+        "set lib_flag()\n"
+        "puts $lib_flag(en)\n"
+        "puts 😀; set lib_flag(em\n"
+    )
+    current = _document(tmp_path / "arrays-current.tcl", source)
+    server.workspace.put_text_document(lsp.TextDocumentItem(
+        uri=current.uri, language_id="tcl", version=1, text=source,
+    ))
+    assert server.update_poco_completion_for_file(current)
+    items = _complete(current, _position_after(source, "set lib_flag(", 3))
+    assert [item.label for item in items] == ["empty", "enabled", "external"]
+    assert all(item.text_edit.new_text == item.label for item in items)
+    items = _complete(current, _position_after(source, "puts $lib_flag(en"))
+    assert [item.label for item in items] == ["enabled"]
+    assert items[0].text_edit.new_text == "enabled"
+    position = lsp.Position(line=6, character=len(source.splitlines()[6].encode("utf-16-le")) // 2)
+    items = _complete(current, position)
+    assert [item.label for item in items] == ["empty"]
+    assert items[0].text_edit.new_text == "empty)"
+    assert items[0].text_edit.range.start.character == position.character - 2
+
+
+def test_dynamic_array_index_keeps_variable_identity(tmp_path: Path, monkeypatch):
+    from tools.navigation import build_file_symbol_index
+    from tools.parser import CustomParser
+    from tools.semantic_tokens import _Highlighter
+    from tools.variable_index import build_variable_index
+    from tools.variable_names import variable_name
+
+    source = (
+        "set custom_flag(from_move,$::mom_path_name) 1\n"
+        'set "::quoted_flag(from_move,$::mom_path_name)" 1\n'
+        "set ::command_flag([info hostname]) 1\n"
+        "set ${dynamic_name}(entry) 1\n"
+        "proc example {} { set local_flag($::mom_path_name) 1 }\n"
+        "puts $custom_flag\n"
+    )
+    tree = CustomParser().parse(source)
+    globals_, locals_, _ = build_variable_index(source, tree)
+    assert {"custom_flag", "quoted_flag", "command_flag"} <= globals_
+    assert locals_["example"] == {"local_flag"}
+    assert variable_name(tree.children[3].args[0]) is None
+    path = tmp_path / "dynamic.tcl"
+    index = build_file_symbol_index(str(path), path.as_uri(), tree)
+    definition = next(
+        item for item in index.occurrences
+        if item.identity.name == "::custom_flag" and item.is_definition
+    )
+    assert definition.range.start.character == 4
+    assert definition.range.end.character == 15
+    assert definition.array_element is None
+    assert any(item.identity.name == "::mom_path_name" for item in index.occurrences)
+    highlighter = _Highlighter([], {})
+    tree.accept(highlighter, recurse=True)
+    assert any(
+        position == (0, 4) and length == 11 and kind == "variable"
+        for position, length, kind, _ in highlighter._tokens
+    )
+    server, _, _ = _completion_server(tmp_path, monkeypatch)
+    current = _document(path, source)
+    server.workspace.put_text_document(lsp.TextDocumentItem(
+        uri=current.uri, language_id="tcl", version=1, text=source,
+    ))
+    assert server.update_poco_completion_for_file(current)
+    items = _complete(current, _position_after(source, "puts $custom"))
+    assert "custom_flag" in {item.label for item in items}
+    workspace_items = next(
+        items for item_path, items in server.completion_items_by_file_snapshot().items()
+        if server.paths_equal(item_path, str(path))
+    )
+    assert {"quoted_flag", "command_flag"} <= {item.label for item in workspace_items}
+
+
+def test_literal_array_components_complete_around_substitutions(tmp_path: Path, monkeypatch):
+    from tools.completion_items import array_element_completions
+
+    server, _, _ = _completion_server(tmp_path, monkeypatch)
+    source = (
+        "set custom_flag(from_move,$::mom_path_name) 1\n"
+        "set custom_flag(to_move,$::mom_path_name) 1\n"
+        "set custom_flag($::mom_path_name,finished) 1\n"
+        "set custom_flag(prefix_$::mom_path_name,other) 1\n"
+        "set custom_flag([info hostname],command_tail) 1\n"
+        "set other_flag(wrong,$::mom_path_name) 1\n"
+        "set multi_flag(move,$first,axis,$second) 1\n"
+    )
+    document = _document(tmp_path / "components.tcl", source)
+    assert server.update_poco_completion_for_file(document)
+    cases = [
+        ("set custom_flag(|,$::mom_path_name)", {"from_move", "to_move"}, "from_move", "set custom_flag(from_move,$::mom_path_name)"),
+        ("set custom_flag(fr|om_old,$::mom_path_name)", {"from_move"}, "from_move", "set custom_flag(from_move,$::mom_path_name)"),
+        ("puts $custom_flag($::mom_path_name,fi|)", {"finished"}, "finished", "puts $custom_flag($::mom_path_name,finished)"),
+        ("set custom_flag($::mom_path_name,|)", {"finished", "other", "command_tail"}, "other", "set custom_flag($::mom_path_name,other)"),
+        ("set custom_flag(fr|", {"from_move"}, "from_move", "set custom_flag(from_move,$::mom_path_name)"),
+        ("set custom_flag(fr|)", {"from_move"}, "from_move", "set custom_flag(from_move,$::mom_path_name)"),
+        ("set multi_flag(m|)", {"move"}, "move", "set multi_flag(move,$first,axis,$second)"),
+    ]
+    for marked, labels, selected, expected in cases:
+        offset = marked.index("|")
+        line = marked.replace("|", "")
+        items = array_element_completions(
+            [line], lsp.Position(line=0, character=offset),
+            server.navigation_snapshot().values(), str(tmp_path / "caller.tcl"),
+        )
+        assert {item.label for item in items} == labels
+        edit = next(item.text_edit for item in items if item.label == selected)
+        item = next(item for item in items if item.label == selected)
+        assert item.insert_text_format == lsp.InsertTextFormat.PlainText
+        assert line[:edit.range.start.character] + edit.new_text + line[edit.range.end.character:] == expected
+    assert array_element_completions(
+        ["set custom_flag(from_move,$::mom"], lsp.Position(line=0, character=31),
+        server.navigation_snapshot().values(), str(tmp_path / "caller.tcl"),
+    ) is None
+
+
 def _argument_completion_request(source: str):
     lines = source.split("\n")
     character = len(lines[-1].encode("utf-16-le")) // 2