Staticscope

ALFA/ALFA.g4

@@ -23,7 +23,11 @@ loopStmt: 'loop' '(' 'int' ID 'from' expr '..' expr ')' block;
 paralStmt: 'paral' paralBlock;
 
 expr
-    : '(' expr ')'                                  #Parens
+    : '-'?NUM                                       #Num
+    | ID                                            #Id
+    | bool                                          #Boolean
+    //Precedence rules
+    | '(' expr ')'                                  #Parens
     | '!' expr                                      #Not
     | '-' expr                                      #UnaryMinus    
     | expr op=('*' | '/' | '%') expr                #MulDiv
@@ -32,9 +36,6 @@ expr
     | expr op=('==' | '!=') expr                    #Equality
     | expr 'and' expr                               #And
     | expr 'or' expr                                #Or
-    | ID                                            #Id
-    | NUM                                           #Num
-    | bool                                          #Boolean
     ;
 
 block: '{' stmt* '}';
@@ -53,7 +54,7 @@ actualParams: (expr (',' expr)*)?;
 
 COMMENT: '#' ~[\r\n]* -> skip;
 ID: [a-zA-Z_][a-zA-Z0-9_]*;
-NUM: '0'| '-'?[1-9][0-9]*;
+NUM: '0'| [1-9][0-9]*;
 type: 'int' | 'bool' | 'rect';
 bool: 'true' | 'false';
-WS: [ \t\r\n]+ -> skip;
+WS: [ \t\r\n]+ -> skip;

ALFA/src/AST Nodes/AssignStmtNode.cs

@@ -7,19 +7,13 @@ public class AssignStmtNode : Node
     public string Identifier { get; set; }
     public Node Value { get; set; }
     public ALFATypes.TypeEnum VarDclParentType { get; set; }
-    
+
     public AssignStmtNode(int line, int col) : base(line, col)
     {
     }
     public AssignStmtNode(string identifier, Node value, int line, int col) : base(line, col)
     {
         Identifier = identifier;
         Value = value;
-    } 
-    public AssignStmtNode(string identifier, Node value, int line, int col, ALFATypes.TypeEnum varDclParentType) : base(line, col)
-    {
-        Identifier = identifier;
-        Value = value;
-        VarDclParentType = varDclParentType;
     }
 }

ALFA/src/AST Nodes/BuiltInAnimCallNode.cs

@@ -4,8 +4,6 @@ namespace ALFA.AST_Nodes;
 
 public class BuiltInAnimCallNode : AnimCallNode<ALFATypes.BuiltInAnimEnum>
 {
-    public override ALFATypes.BuiltInAnimEnum Type { get; set; }
-
     public BuiltInAnimCallNode(ALFATypes.BuiltInAnimEnum type, List<Node> arguments, int line, int col) : base(line, col, arguments)
     {
         Type = type;

ALFA/src/AST Nodes/BuiltInCreateShapeCallNode.cs

@@ -1,12 +1,8 @@
 using ALFA.Types;
 
 namespace ALFA.AST_Nodes;
-
 public class BuiltInCreateShapeCallNode : AnimCallNode<ALFATypes.CreateShapeEnum>
 {
-    public override ALFATypes.CreateShapeEnum Type { get; set; } //createRect
-    public List<Node> Arguments { get; set; } // can consist of NumNode or IdNode
-
 
     public BuiltInCreateShapeCallNode(ALFATypes.CreateShapeEnum type, List<Node> arguments, int line, int col) : base(line, col, arguments)
     {

ALFA/src/AST Nodes/BuiltInParalAnimCallNode.cs

@@ -4,8 +4,6 @@ namespace ALFA.AST_Nodes;
 
 public class BuiltInParalAnimCallNode : AnimCallNode<ALFATypes.BuiltInParalAnimEnum>
 {
-    public override ALFATypes.BuiltInParalAnimEnum Type { get; set; }
-
     public BuiltInParalAnimCallNode(ALFATypes.BuiltInParalAnimEnum type, List<Node> arguments, int line, int col) : base(line, col, arguments)
     {
         Type = type;

ALFA/src/AST Nodes/ExprNode.cs

@@ -15,7 +15,7 @@ public ExprNode(string op, Node left, Node right, int line, int col) : base(line
         Left = left;
         Right = right;
     }
-    public ExprNode(string op, Node left, int line, int col) : base(line, col)
+    public ExprNode(string op, Node left, int line, int col) : base(line, col) // unary
     {
         Operator = op;
         Left = left;

ALFA/src/AST Nodes/IdNode.cs

@@ -4,7 +4,7 @@ public class IdNode : Node
 {
     public string Identifier { get; set; }
     public Node? LocalValue { get; set; }
-    
+
     public IdNode(string identifier, int line, int col) : base(line, col)
     {
         Identifier = identifier;

ALFA/src/Helpers/AnimCallNode.cs

@@ -1,10 +1,14 @@
-namespace ALFA.AST_Nodes;
+using System.Diagnostics.CodeAnalysis;
+
+namespace ALFA.AST_Nodes;
 using ALFA.Types;
 
+[ExcludeFromCodeCoverage]
 public abstract class AnimCallNode<T> : Node
 {
     public List<Node> Arguments { get; set; }
-    public abstract T Type { get; set; } 
+    public T Type { get; set; }
+
     public AnimCallNode(int line, int col, List<Node> arguments) : base(line, col)
     {
         Arguments = arguments;

ALFA/src/Helpers/SymbolTable.cs

@@ -4,101 +4,58 @@ public class SymbolTable
 {
     public int _depth = 0;
     public Dictionary<string, Symbol> _symbols = new();
-    public List<Symbol?>_scopeDisplay = new() {null};  //open the first scope (Global scope) init with null
 
+    public void OpenScope() => _depth++;
 
-    public void OpenScope()
-    {
-        _depth++;
-        if (_scopeDisplay.Count != _depth + 1)
-            _scopeDisplay.Add(null);
-    }
     public void CloseScope()
     {
-        Symbol? sym = _scopeDisplay[_depth];
-        bool removedSymbol = false;
-        Symbol? origSym = _scopeDisplay[_depth];
-        while (sym != null)
+        foreach (var symbol in _symbols.Values.Where(s => s.Depth == _depth))
         {
-            Symbol? prevSymbol = sym.PrevSymbol;
-            // If a variable is declared under the same name in an outer scope (when sym.PrevSymbol != null)
-            // it should be added to the dictionary symbols dictionary.
-            if (prevSymbol != null)
+            if (symbol.PrevSymbol != null)
             {
-                _symbols.Remove(sym.Name);
-                removedSymbol = true;
-                _symbols.Add(prevSymbol.Name, prevSymbol); 
+                _symbols[symbol.Name] = symbol.PrevSymbol;
+                continue;
             }
-
-            sym = prevSymbol;
+            _symbols.Remove(symbol.Name);
         }
 
-        if (!removedSymbol && origSym != null) _symbols.Remove(origSym.Name);
-
         _depth--;
     }
-    
+
     public void EnterSymbol(Symbol symbol)
     {
-        Symbol? oldSymbol = RetrieveSymbol(symbol.Name);
-        if (oldSymbol != null && oldSymbol.Depth == _depth) //
-        {
+        Symbol? oldSymbol = RetrieveSymbol(symbol.Name); // check if symbol already exists
+        if (oldSymbol != null && oldSymbol.Depth == _depth) // if symbol exists in current scope
             throw new VariableAlreadyDeclaredException(
                 $"Symbol {symbol.Name} already declared on line {oldSymbol.LineNumber}:{oldSymbol.ColumnNumber}");
-        }
 
-        Symbol newSymbol = new(symbol.Name, symbol.Value, symbol.Type, symbol.LineNumber, symbol.ColumnNumber);
-        newSymbol.Depth = _depth;
-        _scopeDisplay[_depth] = newSymbol;
+        // no need to construct a new symbol, but still need to update depth
+        symbol.Depth = _depth;
 
-        //If there is a variable declared with the same name on a lower depth
-        if (oldSymbol == null || oldSymbol.Depth < _depth) 
+        // if shadowing
+        if (oldSymbol != null && oldSymbol.Depth < _depth)
         {
-            if (_symbols.ContainsKey(symbol.Name))
-            {
-                oldSymbol = _symbols[symbol.Name];
-                _symbols.Remove(symbol.Name);
-            }
-            _symbols.Add(symbol.Name, newSymbol);
+            symbol.PrevSymbol = oldSymbol;
+            _symbols[oldSymbol.Name] = symbol;
+            return;
         }
 
-        //Sets the oldSymbol with the same name as the newSymbol to be the PrevSymbol
-        //because newSymbol is in the nearest scope with the name.
-        newSymbol.PrevSymbol = oldSymbol!;
+        _symbols.Add(symbol.Name, symbol);
     }
 
-    public Symbol? RetrieveSymbol(string name) 
+    public Symbol? RetrieveSymbol(string name)
     {
         Symbol? sym;
         sym = _symbols.TryGetValue(name, out sym) ? sym : null;
 
         while (sym != null)
         {
-            if (sym.Name == name && sym.Depth <= _depth) 
-            {
+            if (sym.Name == name && sym.Depth <= _depth)
                 return sym;
-            }
 
             sym = sym.PrevSymbol;
         }
 
         return sym;
     }
-
-    public bool DeclaredLocally(string name)
-    {
-        bool isDeclaredLocally = false;
-        Symbol? sym = _scopeDisplay[_depth];
-        while (sym != null)
-        {
-            if (sym.Name == name)
-            {
-                isDeclaredLocally = true;
-            }
-
-            sym = sym.PrevSymbol;
-        }
-
-        return isDeclaredLocally; 
-    }
-}
+}

ALFA/src/Program.cs

@@ -15,7 +15,7 @@ namespace ALFA
     [ExcludeFromCodeCoverage]
     public static class Prog
     {
-        
+
         public static void Main(string[] args)
         {
             string input = String.Empty;
@@ -24,8 +24,6 @@ public static void Main(string[] args)
             if (args.Length == 0)
                 throw new Exception("Missing input arguments. Please provide a .alfa file, example: alfa ./path/to/file.alfa");
 
-
-
             if (args.Contains("--test")) // test mode 
             {
                 input = args[0];
@@ -84,7 +82,7 @@ public static void Main(string[] args)
                 throw new SyntacticException($"Something is syntactically incorrect: {syntacticErrorNode.GetText()} on line {syntacticErrorNode.Payload?.ToString()?.Split(",")[3].Split(":")[0]} column {syntacticErrorNode.Payload.ToString().Split(",")[3].Split(":")[1]}");
             }
 
-            SymbolTable symbolTable = new();
+            SymbolTable symbolTable = new SymbolTable();
             BuildASTVisitor visitor = new BuildASTVisitor(symbolTable);
             Node ast = visitor.Visit(tree);
             TypeCheckVisitor typeCheckVisitor = new TypeCheckVisitor(symbolTable);
@@ -99,7 +97,7 @@ public static void Main(string[] args)
 
         private static ErrorNodeImpl? findErrorNode(IParseTree context)
         {
-            
+
             for (int i = 0; i < context.ChildCount; i++)
             {
                 var child = context.GetChild(i);