From c3f4d8f465fa700a17ebf95222dfdedb1985c4e2 Mon Sep 17 00:00:00 2001
From: Martino Ferrari <martinogiordano.ferrari@iter.org>
Date: Fri, 30 Jan 2026 01:01:47 +0100
Subject: [PATCH] Variable reference from $VAR to @VAR to avoid object conflict

---
 docs/CONFIGURATION_GUIDE.md           |  6 +++---
 internal/builder/builder.go           |  2 +-
 internal/index/index.go               |  2 +-
 internal/lsp/server.go                |  2 +-
 internal/parser/lexer.go              | 14 ++++++++++++++
 internal/parser/parser.go             |  2 +-
 internal/validator/validator.go       |  6 +++---
 test/formatter_variables_test.go      | 13 ++++++-------
 test/lsp_app_test_repro_test.go       |  4 ++--
 test/lsp_binary_test.go               |  2 +-
 test/lsp_diagnostics_app_test.go      |  8 ++++----
 test/lsp_hover_variable_test.go       |  6 +++---
 test/lsp_variable_refs_test.go        |  8 ++++----
 test/operators_test.go                |  6 +++---
 test/regex_variable_test.go           |  2 +-
 test/validator_variable_usage_test.go |  4 ++--
 test/variables_test.go                |  4 ++--
 17 files changed, 52 insertions(+), 39 deletions(-)

diff --git a/docs/CONFIGURATION_GUIDE.md b/docs/CONFIGURATION_GUIDE.md
index 859651c..0ddc6ce 100644
--- a/docs/CONFIGURATION_GUIDE.md
+++ b/docs/CONFIGURATION_GUIDE.md
@@ -173,10 +173,10 @@ You can define variables using `#var`. The type expression supports CUE syntax.
 ```
 
 ### Usage
-Reference a variable using `$`:
+Reference a variable using `@`:
 
 ```marte
-Field = $MyVar
+Field = @MyVar
 ```
 
 ### Expressions
@@ -187,7 +187,7 @@ You can use operators in field values. Supported operators:
 ```marte
 Field1 = 10 + 20 * 2  // 50
 Field2 = "Hello " .. "World"
-Field3 = $MyVar + 5
+Field3 = @MyVar + 5
 ```
 
 ### Build Override
diff --git a/internal/builder/builder.go b/internal/builder/builder.go
index 4435845..7164900 100644
--- a/internal/builder/builder.go
+++ b/internal/builder/builder.go
@@ -235,7 +235,7 @@ func (b *Builder) collectVariables(tree *index.ProjectTree) {
 func (b *Builder) evaluate(val parser.Value) parser.Value {
 	switch v := val.(type) {
 	case *parser.VariableReferenceValue:
-		name := strings.TrimPrefix(v.Name, "$")
+		name := strings.TrimPrefix(v.Name, "@")
 		if res, ok := b.variables[name]; ok {
 			return b.evaluate(res)
 		}
diff --git a/internal/index/index.go b/internal/index/index.go
index ed2faa0..1c237ba 100644
--- a/internal/index/index.go
+++ b/internal/index/index.go
@@ -400,7 +400,7 @@ func (pt *ProjectTree) indexValue(file string, val parser.Value) {
 		})
 	case *parser.VariableReferenceValue:
 		pt.References = append(pt.References, Reference{
-			Name:       strings.TrimPrefix(v.Name, "$"),
+			Name:       strings.TrimPrefix(v.Name, "@"),
 			Position:   v.Position,
 			File:       file,
 			IsVariable: true,
diff --git a/internal/lsp/server.go b/internal/lsp/server.go
index dc7c706..e25ce5b 100644
--- a/internal/lsp/server.go
+++ b/internal/lsp/server.go
@@ -611,7 +611,7 @@ func HandleHover(params HoverParams) *Hover {
 		} else if res.Reference.TargetVariable != nil {
 			v := res.Reference.TargetVariable
 			targetName = v.Name
-			fullInfo = fmt.Sprintf("**Variable**: `%s`\nType: `%s`", v.Name, v.TypeExpr)
+			fullInfo = fmt.Sprintf("**Variable**: `@%s`\nType: `%s`", v.Name, v.TypeExpr)
 			if v.DefaultValue != nil {
 				fullInfo += fmt.Sprintf("\nDefault: `%s`", valueToString(v.DefaultValue))
 			}
diff --git a/internal/parser/lexer.go b/internal/parser/lexer.go
index 313bc9e..2bbead7 100644
--- a/internal/parser/lexer.go
+++ b/internal/parser/lexer.go
@@ -36,6 +36,7 @@ const (
 	TokenCaret
 	TokenAmpersand
 	TokenConcat
+	TokenVariableReference
 )
 
 type Token struct {
@@ -184,6 +185,8 @@ func (l *Lexer) NextToken() Token {
 			return l.lexString()
 		case '#':
 			return l.lexHashIdentifier()
+		case '@':
+			return l.lexVariableReference()
 		case '$':
 			return l.lexObjectIdentifier()
 		}
@@ -311,3 +314,14 @@ func (l *Lexer) lexHashIdentifier() Token {
 	}
 	return l.emit(TokenIdentifier)
 }
+
+func (l *Lexer) lexVariableReference() Token {
+	for {
+		r := l.next()
+		if unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_' || r == '-' {
+			continue
+		}
+		l.backup()
+		return l.emit(TokenVariableReference)
+	}
+}
diff --git a/internal/parser/parser.go b/internal/parser/parser.go
index afbbe88..69e6fa4 100644
--- a/internal/parser/parser.go
+++ b/internal/parser/parser.go
@@ -297,7 +297,7 @@ func (p *Parser) parseAtom() (Value, bool) {
 			true
 	case TokenIdentifier:
 		return &ReferenceValue{Position: tok.Position, Value: tok.Value}, true
-	case TokenObjectIdentifier:
+	case TokenVariableReference:
 		return &VariableReferenceValue{Position: tok.Position, Name: tok.Value}, true
 	case TokenLBrace:
 		arr := &ArrayValue{Position: tok.Position}
diff --git a/internal/validator/validator.go b/internal/validator/validator.go
index ad284a3..6f8741b 100644
--- a/internal/validator/validator.go
+++ b/internal/validator/validator.go
@@ -223,7 +223,7 @@ func (v *Validator) valueToInterface(val parser.Value, ctx *index.ProjectNode) i
 	case *parser.ReferenceValue:
 		return t.Value
 	case *parser.VariableReferenceValue:
-		name := strings.TrimPrefix(t.Name, "$")
+		name := strings.TrimPrefix(t.Name, "@")
 		if info := v.Tree.ResolveVariable(ctx, name); info != nil {
 			if info.Def.DefaultValue != nil {
 				return v.valueToInterface(info.Def.DefaultValue, ctx)
@@ -525,7 +525,7 @@ func (v *Validator) getFieldValue(f *parser.Field, ctx *index.ProjectNode) strin
 	case *parser.BoolValue:
 		return strconv.FormatBool(val.Value)
 	case *parser.VariableReferenceValue:
-		name := strings.TrimPrefix(val.Name, "$")
+		name := strings.TrimPrefix(val.Name, "@")
 		if info := v.Tree.ResolveVariable(ctx, name); info != nil {
 			if info.Def.DefaultValue != nil {
 				return v.getFieldValue(&parser.Field{Value: info.Def.DefaultValue}, ctx)
@@ -1126,7 +1126,7 @@ func (v *Validator) CheckVariables() {
 							if ref.IsVariable && ref.TargetVariable == nil {
 								v.Diagnostics = append(v.Diagnostics, Diagnostic{
 									Level:    LevelError,
-									Message:  fmt.Sprintf("Unresolved variable reference: '$%s'", ref.Name),
+									Message:  fmt.Sprintf("Unresolved variable reference: '@%s'", ref.Name),
 									Position: ref.Position,
 									File:     ref.File,
 								})
diff --git a/test/formatter_variables_test.go b/test/formatter_variables_test.go
index 76d7d5d..a8379bf 100644
--- a/test/formatter_variables_test.go
+++ b/test/formatter_variables_test.go
@@ -15,8 +15,8 @@ func TestFormatterVariables(t *testing.T) {
 #var MyStr: string | "A" = "default"
 
 +Obj = {
-    Field1 = $MyInt
-    Field2 = $MyStr
+    Field1 = @MyInt
+    Field2 = @MyStr
 }
 `
 	p := parser.NewParser(content)
@@ -35,11 +35,10 @@ func TestFormatterVariables(t *testing.T) {
 		t.Errorf("Variable MyInt formatted incorrectly. Got:\n%s", output)
 	}
 	// Note: parser adds space after each token in TypeExpr
-	// string | "A" -> "string | \"A\"" 
+	// string | "A" -> "string | \"A\""
 	if !strings.Contains(output, "#var MyStr: string | \"A\" = \"default\"") {
 		t.Errorf("Variable MyStr formatted incorrectly. Got:\n%s", output)
 	}
-	if !strings.Contains(output, "Field1 = $MyInt") {
-		t.Errorf("Variable reference $MyInt formatted incorrectly. Got:\n%s", output)
-	}
-}
+	if !strings.Contains(output, "Field1 = @MyInt") {
+		t.Errorf("Variable reference @MyInt formatted incorrectly. Got:\n%s", output)
+	}}
diff --git a/test/lsp_app_test_repro_test.go b/test/lsp_app_test_repro_test.go
index ca9bf66..8eca44a 100644
--- a/test/lsp_app_test_repro_test.go
+++ b/test/lsp_app_test_repro_test.go
@@ -38,7 +38,7 @@ func TestLSPAppTestRepro(t *testing.T) {
         A = {
           DataSource = DDB
           Type = uint32
-          Value = $Value
+          Value = @Value
         }
       }
       OutputSignals = {
@@ -75,7 +75,7 @@ func TestLSPAppTestRepro(t *testing.T) {
 	output := buf.String()
 
 	// Check Unresolved Variable
-	if !strings.Contains(output, "Unresolved variable reference: '$Value'") {
+	if !strings.Contains(output, "Unresolved variable reference: '@Value'") {
 		t.Error("LSP missing unresolved variable error")
 	}
 
diff --git a/test/lsp_binary_test.go b/test/lsp_binary_test.go
index a44a258..e304aa6 100644
--- a/test/lsp_binary_test.go
+++ b/test/lsp_binary_test.go
@@ -151,7 +151,7 @@ diags := params["diagnostics"].([]interface{})
 						foundOrdering = true
 						t.Log("Found Ordering error")
 					}
-					if strings.Contains(m, "Unresolved variable reference: '$Value'") {
+					if strings.Contains(m, "Unresolved variable reference: '@Value'") {
 						foundVariable = true
 						t.Log("Found Variable error")
 					}
diff --git a/test/lsp_diagnostics_app_test.go b/test/lsp_diagnostics_app_test.go
index cead575..677092d 100644
--- a/test/lsp_diagnostics_app_test.go
+++ b/test/lsp_diagnostics_app_test.go
@@ -41,7 +41,7 @@ func TestLSPDiagnosticsAppTest(t *testing.T) {
         A = {
           DataSource = DDB
           Type = uint32
-          Value = $Value
+          Value = @Value
         }
       }
       OutputSignals = {
@@ -87,9 +87,9 @@ func TestLSPDiagnosticsAppTest(t *testing.T) {
 		t.Fatal("LSP did not publish diagnostics")
 	}
 
-	// 1. Check Unresolved Variable Error ($Value)
-	if !strings.Contains(output, "Unresolved variable reference: '$Value'") {
-		t.Error("Missing diagnostic for unresolved variable '$Value'")
+	// 1. Check Unresolved Variable Error (@Value)
+	if !strings.Contains(output, "Unresolved variable reference: '@Value'") {
+		t.Error("Missing diagnostic for unresolved variable '@Value'")
 	}
 
 	// 2. Check INOUT Ordering Error (Signal A consumed but not produced)
diff --git a/test/lsp_hover_variable_test.go b/test/lsp_hover_variable_test.go
index 1b35646..944ee1f 100644
--- a/test/lsp_hover_variable_test.go
+++ b/test/lsp_hover_variable_test.go
@@ -16,7 +16,7 @@ func TestLSPHoverVariable(t *testing.T) {
 	content := `
 #var MyInt: int = 123
 +Obj = {
-    Field = $MyInt
+    Field = @MyInt
 }
 `
 	uri := "file://hover_var.marte"
@@ -47,8 +47,8 @@ func TestLSPHoverVariable(t *testing.T) {
 		t.Errorf("Hover def missing default value. Got: %s", contentDef)
 	}
 
-	// 2. Hover on Reference ($MyInt)
-	// Line 4 (index 3). $MyInt is at col 12.
+	// 2. Hover on Reference (@MyInt)
+	// Line 4 (index 3). @MyInt is at col 12.
 	paramsRef := lsp.HoverParams{
 		TextDocument: lsp.TextDocumentIdentifier{URI: uri},
 		Position:     lsp.Position{Line: 3, Character: 12},
diff --git a/test/lsp_variable_refs_test.go b/test/lsp_variable_refs_test.go
index fa44975..3b8b3c1 100644
--- a/test/lsp_variable_refs_test.go
+++ b/test/lsp_variable_refs_test.go
@@ -15,7 +15,7 @@ func TestLSPVariableRefs(t *testing.T) {
 	content := `
 #var MyVar: int = 1
 +Obj = {
-    Field = $MyVar
+    Field = @MyVar
 }
 `
 	uri := "file://vars.marte"
@@ -29,11 +29,11 @@ func TestLSPVariableRefs(t *testing.T) {
 	lsp.Tree.ResolveReferences()
 
 	// 1. Definition from Usage
-	// Line 4: "    Field = $MyVar"
-	// $ is at col 12 (0-based) ?
+	// Line 4: "    Field = @MyVar"
+	// @ is at col 12 (0-based) ?
 	// "    Field = " is 4 + 6 + 3 = 13 chars?
 	// 4 spaces. Field (5). " = " (3). 4+5+3 = 12.
-	// So $ is at 12.
+	// So @ is at 12.
 	paramsDef := lsp.DefinitionParams{
 		TextDocument: lsp.TextDocumentIdentifier{URI: uri},
 		Position:     lsp.Position{Line: 3, Character: 12},
diff --git a/test/operators_test.go b/test/operators_test.go
index c74ecd7..8df7ae1 100644
--- a/test/operators_test.go
+++ b/test/operators_test.go
@@ -17,9 +17,9 @@ func TestOperators(t *testing.T) {
 #var S2: string = "World"
 
 +Obj = {
-    Math = $A + $B
-    Precedence = $A + $B * 2
-    Concat = $S1 .. " " .. $S2
+    Math = @A + @B
+    Precedence = @A + @B * 2
+    Concat = @S1 .. " " .. @S2
 }
 `
 	// Check Parser
diff --git a/test/regex_variable_test.go b/test/regex_variable_test.go
index 3e88d09..c957bdc 100644
--- a/test/regex_variable_test.go
+++ b/test/regex_variable_test.go
@@ -15,7 +15,7 @@ func TestRegexVariable(t *testing.T) {
 #var BadIP: string & =~"^[0-9.]+$" = "abc"
 
 +Obj = {
-    IP = $IP
+    IP = @IP
 }
 `
 	// Test Validator
diff --git a/test/validator_variable_usage_test.go b/test/validator_variable_usage_test.go
index 0d43951..84381b1 100644
--- a/test/validator_variable_usage_test.go
+++ b/test/validator_variable_usage_test.go
@@ -44,7 +44,7 @@ func TestVariableValidation(t *testing.T) {
 #var MyStr: string = "hello"
 +MyPID = {
     Class = PIDGAM
-    Kp = $MyStr
+    Kp = @MyStr
     Ki = 0.0
     Kd = 0.0
 }
@@ -79,7 +79,7 @@ func TestVariableValidation(t *testing.T) {
 #var MyGain: float = 1.5
 +MyPID = {
     Class = PIDGAM
-    Kp = $MyGain
+    Kp = @MyGain
     Ki = 0.0
     Kd = 0.0
 }
diff --git a/test/variables_test.go b/test/variables_test.go
index 2b0637c..ad2794a 100644
--- a/test/variables_test.go
+++ b/test/variables_test.go
@@ -16,8 +16,8 @@ func TestVariables(t *testing.T) {
 
 +Obj = {
     Class = Test
-    Field1 = $MyInt
-    Field2 = $MyStr
+    Field1 = @MyInt
+    Field2 = @MyStr
 }
 `
 	// Test Parsing