Re-implemented functionality

The program now takes in expressions, tokenises, parses, builds an AST and then prints out a truth table.

Author: tomc128

v2/BooleanExpressionParser/.vscode/launch.json

@@ -7,7 +7,10 @@
             "request": "launch",
             "preLaunchTask": "build",
             "program": "${workspaceFolder}/bin/Debug/net6.0/BooleanExpressionParser.dll",
-            "args": [],
+            "args": [
+                "A.B",
+                "A+B"
+            ],
             "cwd": "${workspaceFolder}",
             "console": "integratedTerminal", // enables input (instead of internalConsole)
             "stopAtEntry": false,

v2/BooleanExpressionParser/Evaluator.cs

@@ -9,25 +9,44 @@ public Evaluator(Ast ast)
         Ast = ast;
     }
 
-    public List<bool[]> RunAll()
+    public List<bool[]> EvaluateAll()
     {
         int numCombinations = (int)Math.Pow(2, Ast.Variables.Count);
         var table = new List<bool[]>();
 
         for (int i = 0; i < numCombinations; i++)
         {
             var binary = Convert.ToString(i, 2).PadLeft(Ast.Variables.Count, '0');
-            var row = new bool[Ast.Variables.Count + 1];
+            var values = binary.Select(c => c == '1').ToArray();
 
-            for (int j = 0; j < Ast.Variables.Count; j++)
-            {
-                row[j] = binary[j] == '1';
-            }
+            var result = Evaluate(Ast.Root, values);
+            table.Add(values.Append(result).ToArray());
         }
+
+        return table;
     }
 
-    private bool Evaluate(Node root, bool[] values)
+    private bool Evaluate(Node node, bool[] values)
     {
-        
+        if (node is VariableNode var)
+        {
+            var index = Ast.Variables.IndexOf(var.Name);
+            return values[index];
+        }
+        else if (node is OperatorNode op)
+        {
+            var left = Evaluate(op.Left, values);
+            var right = Evaluate(op.Right!, values);
+
+            if (node is AndOperatorNode) return left && right;
+            if (node is OrOperatorNode) return left || right;
+            if (node is NotOperatorNode) return !left;
+        }
+        else
+        {
+            throw new Exception($"Unknown node type: {node.GetType()}");
+        }
+
+        throw new Exception("This should never happen");
     }
 }

v2/BooleanExpressionParser/Formatter.cs

@@ -62,20 +62,20 @@ public static string FormatPrefixTokens(IEnumerable<Token> tokens)
         return sb.ToString();
     }
 
-    public static string FormatTruthTable(List<string> variables, List<bool[]> table)
+    public static string FormatTruthTable(Ast ast, List<bool[]> table)
     {
         var sb = new StringBuilder();
 
-        sb.AppendLine($"┏{Repeat('━', variables.Count * 3 + 2)}┳{Repeat('━', 8)}┓");
-        sb.AppendLine($"┃  {String.Join("  ", variables)}  ┃ Result ┃");
-        sb.AppendLine($"┣{Repeat('━', variables.Count * 3 + 2)}╋{Repeat('━', 8)}┫");
+        sb.AppendLine($"┏{Repeat('━', ast.Variables.Count * 3 + 2)}┳{Repeat('━', 8)}┓");
+        sb.AppendLine($"┃  {String.Join("  ", ast.Variables)}  ┃ Result ┃");
+        sb.AppendLine($"┣{Repeat('━', ast.Variables.Count * 3 + 2)}╋{Repeat('━', 8)}┫");
 
         foreach (var row in table)
         {
             sb.AppendLine($"┃  {String.Join("  ", row[0..^1].Select(b => b ? "1" : "0"))}  ┃   {(row[^1] ? "1" : "0")}    ┃");
         }
 
-        sb.AppendLine($"┗{Repeat('━', variables.Count * 3 + 2)}┻{Repeat('━', 8)}┛");
+        sb.AppendLine($"┗{Repeat('━', ast.Variables.Count * 3 + 2)}┻{Repeat('━', 8)}┛");
 
         return sb.ToString();
     }

v2/BooleanExpressionParser/Nodes/AndOperatorNode.cs

@@ -1,9 +1,4 @@
 public class AndOperatorNode : OperatorNode
 {
     public AndOperatorNode(Node left, Node right) : base(left, right) { }
-
-    public override bool Evaluate()
-    {
-        return Left.Evaluate() && Right!.Evaluate();
-    }
 }

v2/BooleanExpressionParser/Nodes/Node.cs

@@ -1,6 +1,4 @@
 public abstract class Node
 {
-
-    public abstract bool Evaluate();
 
 }

v2/BooleanExpressionParser/Nodes/NotOperatorNode.cs

@@ -1,9 +1,4 @@
 public class NotOperatorNode : OperatorNode
 {
     public NotOperatorNode(Node left) : base(left, null) { }
-
-    public override bool Evaluate()
-    {
-        return !Left.Evaluate();
-    }
 }

v2/BooleanExpressionParser/Nodes/OperatorNode.cs

@@ -1,6 +1,5 @@
 public abstract class OperatorNode : Node
 {
-
     public OperatorNode(Node left, Node? right)
     {
         Left = left;

v2/BooleanExpressionParser/Nodes/OrOperatorNode.cs

@@ -1,9 +1,4 @@
 public class OrOperatorNode : OperatorNode
 {
     public OrOperatorNode(Node left, Node right) : base(left, right) { }
-
-    public override bool Evaluate()
-    {
-        return Left.Evaluate() || Right!.Evaluate();
-    }
 }

v2/BooleanExpressionParser/Nodes/VariableNode.cs

@@ -7,6 +7,4 @@ public VariableNode(String name)
 
     public String Name { get; set; }
     public bool Value { get; set; }
-
-    public override bool Evaluate() => Value;
 }