improved doc and tests

README.md

@@ -77,6 +77,10 @@ package schema
 
 #Classes: {
     MyCustomGAM: {
+        #meta: {
+            direction: "INOUT"
+            multithreaded: true
+        }
         Param1: int
         Param2?: string
         ...

cmd/mdt/main.go

@@ -86,7 +86,6 @@ func runCheck(args []string) {
 
 	// Legacy loop removed as ValidateProject covers it via recursion
 
-	v.CheckUnused()
 
 	for _, diag := range v.Diagnostics {
 		level := "ERROR"

internal/index/index.go

@@ -13,6 +13,7 @@ type ProjectTree struct {
 	References    []Reference
 	IsolatedFiles map[string]*ProjectNode
 	GlobalPragmas map[string][]string
+	NodeMap       map[string][]*ProjectNode
 }
 
 func (pt *ProjectTree) ScanDirectory(rootPath string) error {
@@ -385,7 +386,19 @@ func (pt *ProjectTree) indexValue(file string, val parser.Value) {
 	}
 }
 
+func (pt *ProjectTree) RebuildIndex() {
+	pt.NodeMap = make(map[string][]*ProjectNode)
+	visitor := func(n *ProjectNode) {
+		pt.NodeMap[n.Name] = append(pt.NodeMap[n.Name], n)
+		if n.RealName != n.Name {
+			pt.NodeMap[n.RealName] = append(pt.NodeMap[n.RealName], n)
+		}
+	}
+	pt.Walk(visitor)
+}
+
 func (pt *ProjectTree) ResolveReferences() {
+	pt.RebuildIndex()
 	for i := range pt.References {
 		ref := &pt.References[i]
 		if isoNode, ok := pt.IsolatedFiles[ref.File]; ok {
@@ -397,14 +410,21 @@ func (pt *ProjectTree) ResolveReferences() {
 }
 
 func (pt *ProjectTree) FindNode(root *ProjectNode, name string, predicate func(*ProjectNode) bool) *ProjectNode {
+	if pt.NodeMap == nil {
+		pt.RebuildIndex()
+	}
+
 	if strings.Contains(name, ".") {
 		parts := strings.Split(name, ".")
 		rootName := parts[0]
 
-		var candidates []*ProjectNode
+		candidates := pt.NodeMap[rootName]
-		pt.findAllNodes(root, rootName, &candidates)
 
 		for _, cand := range candidates {
+			if !pt.isDescendant(cand, root) {
+				continue
+			}
+
 			curr := cand
 			valid := true
 			for i := 1; i < len(parts); i++ {
@@ -426,26 +446,33 @@ func (pt *ProjectTree) FindNode(root *ProjectNode, name string, predicate func(*
 		return nil
 	}
 
-	if root.RealName == name || root.Name == name {
+	candidates := pt.NodeMap[name]
-		if predicate == nil || predicate(root) {
+	for _, cand := range candidates {
-			return root
+		if !pt.isDescendant(cand, root) {
+			continue
 		}
-	}
+		if predicate == nil || predicate(cand) {
-	for _, child := range root.Children {
+			return cand
-		if res := pt.FindNode(child, name, predicate); res != nil {
-			return res
 		}
 	}
 	return nil
 }
 
-func (pt *ProjectTree) findAllNodes(root *ProjectNode, name string, results *[]*ProjectNode) {
+func (pt *ProjectTree) isDescendant(node, root *ProjectNode) bool {
-	if root.RealName == name || root.Name == name {
+	if node == root {
-		*results = append(*results, root)
+		return true
 	}
-	for _, child := range root.Children {
+	if root == nil {
-		pt.findAllNodes(child, name, results)
+		return true
 	}
+	curr := node
+	for curr != nil {
+		if curr == root {
+			return true
+		}
+		curr = curr.Parent
+	}
+	return false
 }
 
 type QueryResult struct {

internal/lsp/server.go

@@ -49,6 +49,7 @@ var Tree = index.NewProjectTree()
 var Documents = make(map[string]string)
 var ProjectRoot string
 var GlobalSchema *schema.Schema
+var Output io.Writer = os.Stdout
 
 type JsonRpcMessage struct {
 	Jsonrpc string          `json:"jsonrpc"`
@@ -91,6 +92,8 @@ type VersionedTextDocumentIdentifier struct {
 }
 
 type TextDocumentContentChangeEvent struct {
+	Range       *Range `json:"range,omitempty"`
+	RangeLength int    `json:"rangeLength,omitempty"`
 	Text        string `json:"text"`
 }
 
@@ -252,7 +255,7 @@ func HandleMessage(msg *JsonRpcMessage) {
 
 		respond(msg.ID, map[string]any{
 			"capabilities": map[string]any{
-				"textDocumentSync":           1, // Full sync
+				"textDocumentSync":           2, // Incremental sync
 				"hoverProvider":              true,
 				"definitionProvider":         true,
 				"referencesProvider":         true,
@@ -346,28 +349,76 @@ func HandleDidOpen(params DidOpenTextDocumentParams) {
 }
 
 func HandleDidChange(params DidChangeTextDocumentParams) {
-	if len(params.ContentChanges) == 0 {
+	uri := params.TextDocument.URI
-		return
+	text, ok := Documents[uri]
+	if !ok {
+		// If not found, rely on full sync being first or error
 	}
-	text := params.ContentChanges[0].Text
+
-	Documents[params.TextDocument.URI] = text
+	for _, change := range params.ContentChanges {
-	path := uriToPath(params.TextDocument.URI)
+		if change.Range == nil {
+			text = change.Text
+		} else {
+			text = applyContentChange(text, change)
+		}
+	}
+
+	Documents[uri] = text
+	path := uriToPath(uri)
 	p := parser.NewParser(text)
 	config, err := p.Parse()
 
 	if err != nil {
-		publishParserError(params.TextDocument.URI, err)
+		publishParserError(uri, err)
 	} else {
-		publishParserError(params.TextDocument.URI, nil)
+		publishParserError(uri, nil)
 	}
 
 	if config != nil {
 		Tree.AddFile(path, config)
 		Tree.ResolveReferences()
-		runValidation(params.TextDocument.URI)
+		runValidation(uri)
 	}
 }
 
+func applyContentChange(text string, change TextDocumentContentChangeEvent) string {
+	startOffset := offsetAt(text, change.Range.Start)
+	endOffset := offsetAt(text, change.Range.End)
+
+	if startOffset == -1 || endOffset == -1 {
+		return text
+	}
+
+	return text[:startOffset] + change.Text + text[endOffset:]
+}
+
+func offsetAt(text string, pos Position) int {
+	line := 0
+	col := 0
+	for i, r := range text {
+		if line == pos.Line && col == pos.Character {
+			return i
+		}
+		if line > pos.Line {
+			break
+		}
+		if r == '\n' {
+			line++
+			col = 0
+		} else {
+			if r >= 0x10000 {
+				col += 2
+			} else {
+				col++
+			}
+		}
+	}
+	if line == pos.Line && col == pos.Character {
+		return len(text)
+	}
+	return -1
+}
+
 func HandleFormatting(params DocumentFormattingParams) []TextEdit {
 	uri := params.TextDocument.URI
 	text, ok := Documents[uri]
@@ -404,7 +455,6 @@ func HandleFormatting(params DocumentFormattingParams) []TextEdit {
 func runValidation(_ string) {
 	v := validator.NewValidator(Tree, ProjectRoot)
 	v.ValidateProject()
-	v.CheckUnused()
 
 	// Group diagnostics by file
 	fileDiags := make(map[string][]LSPDiagnostic)
@@ -646,7 +696,7 @@ func suggestGAMSignals(_ *index.ProjectNode, direction string) *CompletionList {
 
 		dir := "NIL"
 		if GlobalSchema != nil {
-			classPath := cue.ParsePath(fmt.Sprintf("#Classes.%s.direction", cls))
+			classPath := cue.ParsePath(fmt.Sprintf("#Classes.%s.#meta.direction", cls))
 			val := GlobalSchema.Value.LookupPath(classPath)
 			if val.Err() == nil {
 				var s string
@@ -1161,7 +1211,20 @@ func formatNodeInfo(node *index.ProjectNode) string {
 				curr := container
 				for curr != nil {
 					if isGAM(curr) {
-						gams = append(gams, curr.RealName)
+						suffix := ""
+						p := container
+						for p != nil && p != curr {
+							if p.Name == "InputSignals" {
+								suffix = " (Input)"
+								break
+							}
+							if p.Name == "OutputSignals" {
+								suffix = " (Output)"
+								break
+							}
+							p = p.Parent
+						}
+						gams = append(gams, curr.RealName+suffix)
 						break
 					}
 					curr = curr.Parent
@@ -1175,7 +1238,11 @@ func formatNodeInfo(node *index.ProjectNode) string {
 		if n.Target == node {
 			if n.Parent != nil && (n.Parent.Name == "InputSignals" || n.Parent.Name == "OutputSignals") {
 				if n.Parent.Parent != nil && isGAM(n.Parent.Parent) {
-					gams = append(gams, n.Parent.Parent.RealName)
+					suffix := " (Input)"
+					if n.Parent.Name == "OutputSignals" {
+						suffix = " (Output)"
+					}
+					gams = append(gams, n.Parent.Parent.RealName+suffix)
 				}
 			}
 		}
@@ -1342,5 +1409,5 @@ func respond(id any, result any) {
 
 func send(msg any) {
 	body, _ := json.Marshal(msg)
-	fmt.Printf("Content-Length: %d\r\n\r\n%s", len(body), body)
+	fmt.Fprintf(Output, "Content-Length: %d\r\n\r\n%s", len(body), body)
 }

internal/parser/lexer.go

@@ -129,7 +129,7 @@ func (l *Lexer) NextToken() Token {
 		case '/':
 			return l.lexComment()
 		case '#':
-			return l.lexPackage()
+			return l.lexHashIdentifier()
 		case '+':
 			fallthrough
 		case '$':
@@ -243,18 +243,19 @@ func (l *Lexer) lexUntilNewline(t TokenType) Token {
 	}
 }
 
-func (l *Lexer) lexPackage() Token {
+func (l *Lexer) lexHashIdentifier() Token {
 	// We are at '#', l.start is just before it
 	for {
 		r := l.next()
-		if unicode.IsLetter(r) {
+		if unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_' || r == '-' || r == '.' || r == ':' || r == '#' {
 			continue
 		}
 		l.backup()
 		break
 	}
-	if l.input[l.start:l.pos] == "#package" {
+	val := l.input[l.start:l.pos]
+	if val == "#package" {
 		return l.lexUntilNewline(TokenPackage)
 	}
-	return l.emit(TokenError)
+	return l.emit(TokenIdentifier)
 }

internal/schema/marte.cue

@@ -43,7 +43,8 @@ package schema
 		...
 	}
 	TimingDataSource: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	IOGAM: {
@@ -66,71 +67,84 @@ package schema
 	FileDataSource: {
 		Filename:       string
 		Format?:        string
-		direction: "INOUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "INOUT"
 		...
 	}
 	LoggerDataSource: {
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	DANStream: {
 		Timeout?:       int
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	EPICSCAInput: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	EPICSCAOutput: {
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	EPICSPVAInput: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	EPICSPVAOutput: {
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	SDNSubscriber: {
 		Address:        string
 		Port:           int
 		Interface?:     string
-		direction:  "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	SDNPublisher: {
 		Address:        string
 		Port:           int
 		Interface?:     string
-		direction:  "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	UDPReceiver: {
 		Port:           int
 		Address?:       string
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	UDPSender: {
 		Destination:    string
-		direction:   "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	FileReader: {
 		Filename:       string
 		Format?:        string
 		Interpolate?:   string
-		direction:    "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	FileWriter: {
 		Filename:        string
 		Format?:         string
 		StoreOnTrigger?: int
-		direction:       "OUT"
+		#meta: multithreaded:  bool | *false
+		#meta: direction:      "OUT"
 		...
 	}
 	OrderedClass: {
@@ -173,7 +187,8 @@ package schema
 	TriggeredIOGAM: {...}
 	WaveformGAM: {...}
 	DAN: {
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	LinuxTimer: {
@@ -184,11 +199,13 @@ package schema
 		CPUMask?:         int
 		TimeProvider?: {...}
 		Signals: {...}
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	LinkDataSource: {
-		direction: "INOUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "INOUT"
 		...
 	}
 	MDSReader: {
@@ -196,7 +213,8 @@ package schema
 		ShotNumber: int
 		Frequency:  float | int
 		Signals: {...}
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	MDSWriter: {
@@ -212,57 +230,74 @@ package schema
 		NumberOfPostTriggers?: int
 		Signals: {...}
 		Messages?: {...}
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	NI1588TimeStamp: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	NI6259ADC: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	NI6259DAC: {
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	NI6259DIO: {
-		direction: "INOUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "INOUT"
 		...
 	}
 	NI6368ADC: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	NI6368DAC: {
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
 		...
 	}
 	NI6368DIO: {
-		direction: "INOUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "INOUT"
 		...
 	}
 	NI9157CircularFifoReader: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	NI9157MxiDataSource: {
-		direction: "INOUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "INOUT"
 		...
 	}
 	OPCUADSInput: {
-		direction: "IN"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "IN"
 		...
 	}
 	OPCUADSOutput: {
-		direction: "OUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "OUT"
+		...
+	}
+	RealTimeThreadAsyncBridge: {
+		#meta: direction:     "INOUT"
+		#meta: multithreaded: bool | true
 		...
 	}
-	RealTimeThreadAsyncBridge: {...}
 	RealTimeThreadSynchronisation: {...}
 	UARTDataSource: {
-		direction: "INOUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "INOUT"
 		...
 	}
 	BaseLib2Wrapper: {...}
@@ -272,7 +307,8 @@ package schema
 	OPCUA: {...}
 	SysLogger: {...}
 	GAMDataSource: {
-		direction: "INOUT"
+		#meta: multithreaded: bool | *false
+		#meta: direction:     "INOUT"
 		...
 	}
 }

internal/validator/validator.go

@@ -53,6 +53,8 @@ func (v *Validator) ValidateProject() {
 	for _, node := range v.Tree.IsolatedFiles {
 		v.validateNode(node)
 	}
+	v.CheckUnused()
+	v.CheckDataSourceThreading()
 }
 
 func (v *Validator) validateNode(node *index.ProjectNode) {
@@ -313,8 +315,8 @@ func (v *Validator) validateGAMSignal(gamNode, signalNode *index.ProjectNode, di
 	dsClass := v.getNodeClass(dsNode)
 	if dsClass != "" {
 		// Lookup class definition in Schema
-		// path: #Classes.ClassName.direction
+		// path: #Classes.ClassName.#meta.direction
-		path := cue.ParsePath(fmt.Sprintf("#Classes.%s.direction", dsClass))
+		path := cue.ParsePath(fmt.Sprintf("#Classes.%s.#meta.direction", dsClass))
 		val := v.Schema.Value.LookupPath(path)
 
 		if val.Err() == nil {
@@ -509,6 +511,8 @@ func (v *Validator) getFieldValue(f *parser.Field) string {
 		return val.Raw
 	case *parser.FloatValue:
 		return val.Raw
+	case *parser.BoolValue:
+		return strconv.FormatBool(val.Value)
 	}
 	return ""
 }
@@ -741,3 +745,142 @@ func (v *Validator) isGloballyAllowed(warningType string, contextFile string) bo
 	}
 	return false
 }
+
+func (v *Validator) CheckDataSourceThreading() {
+	if v.Tree.Root == nil {
+		return
+	}
+
+	// 1. Find RealTimeApplication
+	var appNode *index.ProjectNode
+	findApp := func(n *index.ProjectNode) {
+		if cls, ok := n.Metadata["Class"]; ok && cls == "RealTimeApplication" {
+			appNode = n
+		}
+	}
+	v.Tree.Walk(findApp)
+
+	if appNode == nil {
+		return
+	}
+
+	// 2. Find States
+	var statesNode *index.ProjectNode
+	if s, ok := appNode.Children["States"]; ok {
+		statesNode = s
+	} else {
+		for _, child := range appNode.Children {
+			if cls, ok := child.Metadata["Class"]; ok && cls == "StateMachine" {
+				statesNode = child
+				break
+			}
+		}
+	}
+
+	if statesNode == nil {
+		return
+	}
+
+	// 3. Iterate States
+	for _, state := range statesNode.Children {
+		dsUsage := make(map[*index.ProjectNode]string) // DS Node -> Thread Name
+		var threads []*index.ProjectNode
+
+		// Search for threads in the state (either direct children or inside "Threads" container)
+		for _, child := range state.Children {
+			if child.RealName == "Threads" {
+				for _, t := range child.Children {
+					if cls, ok := t.Metadata["Class"]; ok && cls == "RealTimeThread" {
+						threads = append(threads, t)
+					}
+				}
+			} else {
+				if cls, ok := child.Metadata["Class"]; ok && cls == "RealTimeThread" {
+					threads = append(threads, child)
+				}
+			}
+		}
+
+		for _, thread := range threads {
+			gams := v.getThreadGAMs(thread)
+			for _, gam := range gams {
+				dss := v.getGAMDataSources(gam)
+				for _, ds := range dss {
+					if existingThread, ok := dsUsage[ds]; ok {
+						if existingThread != thread.RealName {
+							if !v.isMultithreaded(ds) {
+								v.Diagnostics = append(v.Diagnostics, Diagnostic{
+									Level:    LevelError,
+									Message:  fmt.Sprintf("DataSource '%s' is not multithreaded but used in multiple threads (%s, %s) in state '%s'", ds.RealName, existingThread, thread.RealName, state.RealName),
+									Position: v.getNodePosition(gam),
+									File:     v.getNodeFile(gam),
+								})
+							}
+						}
+					} else {
+						dsUsage[ds] = thread.RealName
+					}
+				}
+			}
+		}
+	}
+}
+
+func (v *Validator) getThreadGAMs(thread *index.ProjectNode) []*index.ProjectNode {
+	var gams []*index.ProjectNode
+	fields := v.getFields(thread)
+	if funcs, ok := fields["Functions"]; ok && len(funcs) > 0 {
+		f := funcs[0]
+		if arr, ok := f.Value.(*parser.ArrayValue); ok {
+			for _, elem := range arr.Elements {
+				if ref, ok := elem.(*parser.ReferenceValue); ok {
+					target := v.resolveReference(ref.Value, v.getNodeFile(thread), isGAM)
+					if target != nil {
+						gams = append(gams, target)
+					}
+				}
+			}
+		}
+	}
+	return gams
+}
+
+func (v *Validator) getGAMDataSources(gam *index.ProjectNode) []*index.ProjectNode {
+	dsMap := make(map[*index.ProjectNode]bool)
+
+	processSignals := func(container *index.ProjectNode) {
+		if container == nil {
+			return
+		}
+		for _, sig := range container.Children {
+			fields := v.getFields(sig)
+			if dsFields, ok := fields["DataSource"]; ok && len(dsFields) > 0 {
+				dsName := v.getFieldValue(dsFields[0])
+				dsNode := v.resolveReference(dsName, v.getNodeFile(sig), isDataSource)
+				if dsNode != nil {
+					dsMap[dsNode] = true
+				}
+			}
+		}
+	}
+
+	processSignals(gam.Children["InputSignals"])
+	processSignals(gam.Children["OutputSignals"])
+
+	var dss []*index.ProjectNode
+	for ds := range dsMap {
+		dss = append(dss, ds)
+	}
+	return dss
+}
+
+func (v *Validator) isMultithreaded(ds *index.ProjectNode) bool {
+	if meta, ok := ds.Children["#meta"]; ok {
+		fields := v.getFields(meta)
+		if mt, ok := fields["multithreaded"]; ok && len(mt) > 0 {
+			val := v.getFieldValue(mt[0])
+			return val == "true"
+		}
+	}
+	return false
+}

specification.md

@@ -21,11 +21,12 @@ The executable should support the following subcommands:
 The LSP server should provide the following capabilities:
 
 - **Diagnostics**: Report syntax errors and validation issues.
+- **Incremental Sync**: Supports `textDocumentSync` kind 2 (Incremental) for better performance with large files.
 - **Hover Documentation**:
   - **Objects**: Display `CLASS::Name` and any associated docstrings.
   - **Signals**: Display `DataSource.Name TYPE (SIZE) [IN/OUT/INOUT]` along with docstrings.
   - **GAMs**: Show the list of States where the GAM is referenced.
-  - **Referenced Signals**: Show the list of GAMs where the signal is referenced.
+  - **Referenced Signals**: Show the list of GAMs where the signal is referenced (indicating Input/Output direction).
 - **Go to Definition**: Jump to the definition of a reference, supporting navigation across any file in the current project.
 - **Go to References**: Find usages of a node or field, supporting navigation across any file in the current project.
 - **Code Completion**: Autocomplete fields, values, and references.
@@ -173,6 +174,7 @@ The tool must build an index of the configuration to support LSP features and va
     - **Conditional Fields**: Validation of fields whose presence or value depends on the values of other fields within the same node or context.
   - **Schema Definition**:
     - Class validation rules must be defined in a separate schema file using the **CUE** language.
+    - **Metadata**: Class properties like direction (`#direction`) and multithreading support (`#multithreaded`) are stored within a `#meta` field in the class definition (e.g., `#meta: { direction: "IN", multithreaded: true }`).
     - **Project-Specific Classes**: Developers can define their own project-specific classes and corresponding validation rules, expanding the validation capabilities for their specific needs.
   - **Schema Loading**:
     - **Default Schema**: The tool should look for a default schema file `marte_schema.cue` in standard system locations:
@@ -218,6 +220,7 @@ The LSP and `check` command should report the following:
     - Field type mismatches.
     - Grammar errors (e.g., missing closing brackets).
     - **Invalid Function Reference**: Elements in the `Functions` array of a `State.Thread` must be valid references to defined GAM nodes.
+  - **Threading Violation**: A DataSource that is not marked as multithreaded (via `#meta.multithreaded`) is used by GAMs running in different threads within the same State.
 
 ## Logging
 

test/ast_test.go

@@ -0,0 +1,94 @@
+package integration
+
+import (
+	"testing"
+
+	"github.com/marte-community/marte-dev-tools/internal/parser"
+)
+
+func TestASTCoverage(t *testing.T) {
+	pos := parser.Position{Line: 1, Column: 1}
+
+	var n parser.Node
+	// var d parser.Definition // Definition has unexported method, can't assign?
+	// Yes I can assign if I am using the interface type exported by parser.
+	// But I cannot call the method.
+	var d parser.Definition
+	var v parser.Value
+
+	// Field
+	f := &parser.Field{Position: pos}
+	n = f
+	d = f
+	if n.Pos() != pos {
+		t.Error("Field.Pos failed")
+	}
+	_ = d
+
+	// ObjectNode
+	o := &parser.ObjectNode{Position: pos}
+	n = o
+	d = o
+	if n.Pos() != pos {
+		t.Error("ObjectNode.Pos failed")
+	}
+
+	// StringValue
+	sv := &parser.StringValue{Position: pos}
+	n = sv
+	v = sv
+	if n.Pos() != pos {
+		t.Error("StringValue.Pos failed")
+	}
+	_ = v
+
+	// IntValue
+	iv := &parser.IntValue{Position: pos}
+	n = iv
+	v = iv
+	if n.Pos() != pos {
+		t.Error("IntValue.Pos failed")
+	}
+
+	// FloatValue
+	fv := &parser.FloatValue{Position: pos}
+	n = fv
+	v = fv
+	if n.Pos() != pos {
+		t.Error("FloatValue.Pos failed")
+	}
+
+	// BoolValue
+	bv := &parser.BoolValue{Position: pos}
+	n = bv
+	v = bv
+	if n.Pos() != pos {
+		t.Error("BoolValue.Pos failed")
+	}
+
+	// ReferenceValue
+	rv := &parser.ReferenceValue{Position: pos}
+	n = rv
+	v = rv
+	if n.Pos() != pos {
+		t.Error("ReferenceValue.Pos failed")
+	}
+
+	// ArrayValue
+	av := &parser.ArrayValue{Position: pos}
+	n = av
+	v = av
+	if n.Pos() != pos {
+		t.Error("ArrayValue.Pos failed")
+	}
+
+	// Package
+	pkg := &parser.Package{Position: pos}
+	// Package implements Node?
+	// ast.go: func (p *Package) Pos() Position { return p.Position }
+	// Yes.
+	n = pkg
+	if n.Pos() != pos {
+		t.Error("Package.Pos failed")
+	}
+}

test/index_test.go

@@ -0,0 +1,66 @@
+package integration
+
+import (
+	"testing"
+
+	"github.com/marte-community/marte-dev-tools/internal/index"
+)
+
+func TestNodeMap(t *testing.T) {
+	pt := index.NewProjectTree()
+	root := pt.Root
+
+	// Create structure: +A -> +B -> +C
+	nodeA := &index.ProjectNode{Name: "A", RealName: "+A", Children: make(map[string]*index.ProjectNode), Parent: root}
+	root.Children["A"] = nodeA
+
+	nodeB := &index.ProjectNode{Name: "B", RealName: "+B", Children: make(map[string]*index.ProjectNode), Parent: nodeA}
+	nodeA.Children["B"] = nodeB
+
+	nodeC := &index.ProjectNode{Name: "C", RealName: "+C", Children: make(map[string]*index.ProjectNode), Parent: nodeB}
+	nodeB.Children["C"] = nodeC
+
+	// Rebuild Index
+	pt.RebuildIndex()
+
+	// Find by Name
+	found := pt.FindNode(root, "C", nil)
+	if found != nodeC {
+		t.Errorf("FindNode(C) failed. Got %v, want %v", found, nodeC)
+	}
+
+	// Find by RealName
+	found = pt.FindNode(root, "+C", nil)
+	if found != nodeC {
+		t.Errorf("FindNode(+C) failed. Got %v, want %v", found, nodeC)
+	}
+
+	// Find by Path
+	found = pt.FindNode(root, "A.B.C", nil)
+	if found != nodeC {
+		t.Errorf("FindNode(A.B.C) failed. Got %v, want %v", found, nodeC)
+	}
+
+	// Find by Path with RealName
+	found = pt.FindNode(root, "+A.+B.+C", nil)
+	if found != nodeC {
+		t.Errorf("FindNode(+A.+B.+C) failed. Got %v, want %v", found, nodeC)
+	}
+}
+
+func TestResolveReferencesWithMap(t *testing.T) {
+	pt := index.NewProjectTree()
+	root := pt.Root
+
+	nodeA := &index.ProjectNode{Name: "A", RealName: "+A", Children: make(map[string]*index.ProjectNode), Parent: root}
+	root.Children["A"] = nodeA
+
+	ref := index.Reference{Name: "A", File: "test.marte"}
+	pt.References = append(pt.References, ref)
+
+	pt.ResolveReferences()
+
+	if pt.References[0].Target != nodeA {
+		t.Error("ResolveReferences failed to resolve A")
+	}
+}

test/lsp_completion_signals_robustness_test.go

@@ -20,7 +20,7 @@ func TestSuggestSignalsRobustness(t *testing.T) {
 	custom := []byte(`
 package schema
 #Classes: {
-    InOutReader: { direction: "INOUT" }
+    InOutReader: { #meta: direction: "INOUT" }
 }
 `)
 	val := lsp.GlobalSchema.Context.CompileBytes(custom)

test/lsp_validation_threading_test.go

@@ -0,0 +1,77 @@
+package integration
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+
+	"github.com/marte-community/marte-dev-tools/internal/index"
+	"github.com/marte-community/marte-dev-tools/internal/lsp"
+	"github.com/marte-community/marte-dev-tools/internal/schema"
+)
+
+func TestLSPValidationThreading(t *testing.T) {
+	// Setup
+	lsp.Tree = index.NewProjectTree()
+	lsp.Documents = make(map[string]string)
+	lsp.ProjectRoot = "."
+	lsp.GlobalSchema = schema.NewSchema() // Empty schema but not nil
+
+	// Capture Output
+	var buf bytes.Buffer
+	lsp.Output = &buf
+
+	content := `
++Data = {
+    Class = ReferenceContainer
+    +SharedDS = {
+        Class = GAMDataSource
+        #meta = {
+            direction = "INOUT"
+            multithreaded = false
+        }
+        Signals = {
+            Sig1 = { Type = uint32 }
+        }
+    }
+}
++GAM1 = { Class = IOGAM InputSignals = { Sig1 = { DataSource = SharedDS Type = uint32 } } }
++GAM2 = { Class = IOGAM OutputSignals = { Sig1 = { DataSource = SharedDS Type = uint32 } } }
++App = {
+    Class = RealTimeApplication
+    +States = {
+        Class = ReferenceContainer
+        +State1 = {
+            Class = RealTimeState
+            +Thread1 = { Class = RealTimeThread Functions = { GAM1 } }
+            +Thread2 = { Class = RealTimeThread Functions = { GAM2 } }
+        }
+    }
+}
+`
+	uri := "file://threading.marte"
+
+	// Call HandleDidOpen directly
+	params := lsp.DidOpenTextDocumentParams{
+		TextDocument: lsp.TextDocumentItem{
+			URI:  uri,
+			Text: content,
+		},
+	}
+
+	lsp.HandleDidOpen(params)
+
+	// Check output
+	output := buf.String()
+	
+	// We look for publishDiagnostics notification
+	if !strings.Contains(output, "textDocument/publishDiagnostics") {
+		t.Fatal("Did not receive publishDiagnostics")
+	}
+
+	// We look for the specific error message
+	expectedError := "DataSource '+SharedDS' is not multithreaded but used in multiple threads"
+	if !strings.Contains(output, expectedError) {
+		t.Errorf("Expected error '%s' not found in LSP output. Output:\n%s", expectedError, output)
+	}
+}

test/validator_datasource_threading_test.go

@@ -0,0 +1,124 @@
+package integration
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/marte-community/marte-dev-tools/internal/index"
+	"github.com/marte-community/marte-dev-tools/internal/parser"
+	"github.com/marte-community/marte-dev-tools/internal/validator"
+)
+
+func TestDataSourceThreadingValidation(t *testing.T) {
+	content := `
++Data = {
+    Class = ReferenceContainer
+    +SharedDS = {
+        Class = GAMDataSource
+        #meta = {
+            direction = "INOUT"
+            multithreaded = false
+        }
+        Signals = {
+            Sig1 = { Type = uint32 }
+        }
+    }
+    +MultiDS = {
+        Class = GAMDataSource
+        #meta = {
+            direction = "INOUT"
+            multithreaded = true
+        }
+        Signals = {
+            Sig1 = { Type = uint32 }
+        }
+    }
+}
++GAM1 = {
+    Class = IOGAM
+    InputSignals = {
+        Sig1 = { DataSource = SharedDS Type = uint32 }
+    }
+}
++GAM2 = {
+    Class = IOGAM
+    OutputSignals = {
+        Sig1 = { DataSource = SharedDS Type = uint32 }
+    }
+}
++GAM3 = {
+    Class = IOGAM
+    InputSignals = {
+        Sig1 = { DataSource = MultiDS Type = uint32 }
+    }
+}
++GAM4 = {
+    Class = IOGAM
+    OutputSignals = {
+        Sig1 = { DataSource = MultiDS Type = uint32 }
+    }
+}
++App = {
+    Class = RealTimeApplication
+    +States = {
+        Class = ReferenceContainer
+        +State1 = {
+            Class = RealTimeState
+            +Thread1 = {
+                Class = RealTimeThread
+                Functions = { GAM1 }
+            }
+            +Thread2 = {
+                Class = RealTimeThread
+                Functions = { GAM2 }
+            }
+        }
+        +State2 = {
+            Class = RealTimeState
+            +Thread1 = {
+                Class = RealTimeThread
+                Functions = { GAM3 }
+            }
+            +Thread2 = {
+                Class = RealTimeThread
+                Functions = { GAM4 }
+            }
+        }
+    }
+}
+`
+	pt := index.NewProjectTree()
+	p := parser.NewParser(content)
+	cfg, err := p.Parse()
+	if err != nil {
+		t.Fatal(err)
+	}
+	pt.AddFile("main.marte", cfg)
+
+	// Since we don't load schema here (empty path), it won't validate classes via CUE,
+	// but CheckDataSourceThreading relies on parsing logic, not CUE schema unification.
+	// So it should work.
+
+	v := validator.NewValidator(pt, "")
+	v.ValidateProject()
+
+	foundError := false
+	for _, d := range v.Diagnostics {
+		if strings.Contains(d.Message, "not multithreaded but used in multiple threads") {
+			if strings.Contains(d.Message, "SharedDS") {
+				foundError = true
+			}
+			if strings.Contains(d.Message, "MultiDS") {
+				t.Error("Unexpected threading error for MultiDS")
+			}
+		}
+	}
+
+	if !foundError {
+		t.Error("Expected threading error for SharedDS")
+		// Debug
+		for _, d := range v.Diagnostics {
+			t.Logf("Diag: %s", d.Message)
+		}
+	}
+}

test/validator_gam_signals_linking_test.go

@@ -23,6 +23,7 @@ func TestGAMSignalLinking(t *testing.T) {
 
 +MyGAM = {
     Class = IOGAM
+    //! ignore(unused)
     InputSignals = {
         MySig = {
             DataSource = MyDS