Basic Calculator with expression parsing

MicroUI.cs/MicroUI.cs

@@ -10,15 +10,15 @@ namespace MicroUI
     {
         public const string Version = "1.0.0";
         public const int CommandListSize = 256 * 1024;
-        public const int RootListSize = 32;
+        public const int RootListSize = 256;
-        public const int ContainerStackSize = 32;
+        public const int ContainerStackSize = 256;
-        public const int ClipStackSize = 32;
+        public const int ClipStackSize = 256;
-        public const int IdStackSize = 32;
+        public const int IdStackSize = 256;
-        public const int LayoutStackSize = 16;
+        public const int LayoutStackSize = 256;
-        public const int ContainerPoolSize = 48;
+        public const int ContainerPoolSize = 256;
-        public const int TreeNodePoolSize = 48;
+        public const int TreeNodePoolSize = 256;
-        public const int MaxWidths = 16;
+        public const int MaxWidths = 256;
-        public const int MaxFormatLength = 127;
+        public const int MaxFormatLength = 256;
     }
     
     public static class Format

MicroUI.cs/Program.cs

@@ -1,324 +1,347 @@
 using Raylib_cs;
 using MicroUI;
-using System.Numerics;
+using System;
+using System.Collections.Generic;
+using System.Linq;
 
 namespace MicroUI;
 
 class Program
 {
-    // Key state tracking for key up events
+    private static string display = "0";
-    private static HashSet<int> pressedKeys = new HashSet<int>();
+    private static string expression = "";
-    // Persistent textbox value
+    private static string lastOperation = "";
-    private static string textboxValue = "test";
+    private static double lastResult = 0;
-    // Second number value for testing multiple number controls
+    private static bool evaluated = false;
-    private static float secondValue = 25.0f;
+    private static string currentInput = "";
-    // Track focus changes
+
-    private static uint lastFocus = 0;
+    private static readonly string[,] keys =
-    
+    {
-    // STAThread is required if you deploy using NativeAOT on Windows - See https://github.com/raylib-cs/raylib-cs/issues/301
+        { "7", "8", "9", "/" },
+        { "4", "5", "6", "*" },
+        { "1", "2", "3", "-" },
+        { "0", "(", ")", "+" }
+    };
+
     [STAThread]
     public static void Main()
     {
-        Raylib.InitWindow(800, 480, "Hello World");
+        const int winW = 300;
-
+        const int winH = 450;
-        // Create microui context
+        Raylib.SetConfigFlags(ConfigFlags.ResizableWindow);
-            var ctx = new MuContext();
+        Raylib.InitWindow(800, 600, "Calculator");
-
+        var ctx = new MuContext();
-            // Set up required callbacks
+        ctx.TextWidth = (object font, string str, int len) => Raylib.MeasureText(str, 20);
-            ctx.TextWidth = (object font, string str, int len) =>
+        ctx.TextHeight = (object font) => 24;
-            {
+        MicroUI.Init(ctx);
-                // Use Raylib's MeasureText to get actual text width
-                // If font is null, use default font, otherwise cast to Font
-                Font textFont = font as Font? ?? Raylib.GetFontDefault();
-                return Raylib.MeasureText(str, 10); // 16 is font size
-            };
-
-            ctx.TextHeight = (object font) =>
-            {
-                // Use Raylib's font height measurement
-                Font textFont = font as Font? ?? Raylib.GetFontDefault();
-                return 10; // Return a fixed height for now, or use textFont.baseSize if available
-            };
-            // Initialize microui
-            MicroUI.Init(ctx);
-
-        bool isChecked = false;
-        float sliderValue = 50.0f; // Remove persistent slider value
-
 
         while (!Raylib.WindowShouldClose())
         {
-            // Handle input
             var mousePos = Raylib.GetMousePosition();
             MuInput.MouseMove(ctx, (int)mousePos.X, (int)mousePos.Y);
-            
-            // Track focus changes in main loop
-            if (ctx.Focus != lastFocus)
-            {
-                lastFocus = ctx.Focus;
-            }
-            
             if (Raylib.IsMouseButtonPressed(Raylib_cs.MouseButton.Left))
-            {
+                MuInput.MouseDown(ctx, (int)mousePos.X, (int)mousePos.Y, (int)MouseButton.Left);
-                MuInput.MouseDown(ctx, (int)mousePos.X, (int)mousePos.Y, 1);
-            }
-            else if (Raylib.IsMouseButtonDown(Raylib_cs.MouseButton.Left))
-            {
-                // Keep MouseDown state active while button is held
-                ctx.MouseDown = 1;
-            }
             if (Raylib.IsMouseButtonReleased(Raylib_cs.MouseButton.Left))
-            {
+                MuInput.MouseUp(ctx, (int)mousePos.X, (int)mousePos.Y, (int)MouseButton.Left);
-                MuInput.MouseUp(ctx, (int)mousePos.X, (int)mousePos.Y, 1);
+
-            }
+            Raylib.BeginDrawing();
-            
+            Raylib.ClearBackground(Color.DarkGray);
-            // Handle keyboard input - only for modifier keys
-            int key = Raylib.GetKeyPressed();
-            if (key != 0)
-            {
-                // Only handle modifier keys here, not regular characters
-                // Regular characters are handled in the text input section below
-                if (key == (int)KeyboardKey.Enter || key == (int)KeyboardKey.Backspace)
-                {
-                    // Convert to MicroUI key modifiers
-                    int muKey = 0;
-                    if (key == (int)KeyboardKey.Enter) muKey = (int)KeyModifiers.Return;
-                    if (key == (int)KeyboardKey.Backspace) muKey = (int)KeyModifiers.Backspace;
-                    
-                    MuInput.KeyDown(ctx, muKey);
-                    pressedKeys.Add(muKey);
-                }
-            }
-            
-            // Handle Shift key state (for Shift+Click functionality)
-            if (Raylib.IsKeyDown(KeyboardKey.LeftShift) || Raylib.IsKeyDown(KeyboardKey.RightShift))
-            {
-                ctx.KeyDown |= (int)KeyModifiers.Shift;
-            }
-            else
-            {
-                ctx.KeyDown &= ~(int)KeyModifiers.Shift;
-            }
-            
-            // Handle key up events for modifier keys
-            var keysToRemove = new List<int>();
-            foreach (int pressedKey in pressedKeys)
-            {
-                // Convert back from MicroUI key modifiers to Raylib keys for checking
-                KeyboardKey raylibKey = KeyboardKey.Null;
-                if (pressedKey == (int)KeyModifiers.Return) raylibKey = KeyboardKey.Enter;
-                if (pressedKey == (int)KeyModifiers.Backspace) raylibKey = KeyboardKey.Backspace;
-                
-                if (raylibKey != KeyboardKey.Null && !Raylib.IsKeyDown(raylibKey))
-                {
-                    MuInput.KeyUp(ctx, pressedKey);
-                    keysToRemove.Add(pressedKey);
-                }
-            }
-            foreach (int keyToRemove in keysToRemove)
-            {
-                pressedKeys.Remove(keyToRemove);
-            }
-            
-            // Handle text input
-            int keyChar;
-            while ((keyChar = Raylib.GetCharPressed()) != 0)
-            {
-                char typedChar = (char)keyChar;
-                MuInput.InputText(ctx, typedChar.ToString());
-            }
-            // Debug print for KeyPressed (commented out to reduce noise)
-            // Console.WriteLine($"DEBUG: KeyPressed after input: {ctx.KeyPressed}");
-            
-            Raylib.BeginDrawing();
-            Raylib.ClearBackground(Color.Black);
 
-            // Begin frame
             MicroUI.Begin(ctx);
-            
+
-            for(int i = 0; i < 1; i++){
+            var winX = (Raylib.GetScreenWidth() - winW) / 2;
-                Window(ctx, i * 15, i * 15, i, ref isChecked, ref sliderValue); // Remove ref sliderValue
+            var winY = (Raylib.GetScreenHeight() - winH) / 2;
+            if (MuControl.BeginWindowEx(ctx, "Calculator", new MuRect(winX, winY, winW, winH), (int)Options.NoClose))
+            {
+                var container = MicroUI.GetCurrentContainer(ctx);
+                var availableWidth = container.Body.W - 32;
+                var buttonWidth = availableWidth / 4;
+                var buttonHeight = 48;
+
+                MuLayoutUtil.LayoutRow(ctx, 1, new int[] { availableWidth }, 48);
+                string toShow = display == "Error" ? "Error" : (evaluated ? display : (expression.Length > 0 ? expression : "0"));
+                MuRect displayRect = MuLayoutUtil.LayoutNext(ctx);
+                MuControl.DrawControlText(ctx, toShow, displayRect, ColorType.Text, (int)Options.AlignRight);
+
+                for (int row = 0; row < 4; row++)
+                {
+                    MuLayoutUtil.LayoutRow(ctx, 4, new int[] { buttonWidth, buttonWidth, buttonWidth, buttonWidth }, buttonHeight);
+                    for (int col = 0; col < 4; col++)
+                    {
+                        string key = keys[row, col];
+                        if (MuControl.ButtonEx(ctx, key, 0, (int)Options.AlignCenter).Flags.HasFlag(ResultFlags.Submit))
+                            HandleKey(key);
+                    }
+                }
+
+                MuLayoutUtil.LayoutRow(ctx, 4, new int[] { buttonWidth, buttonWidth, buttonWidth, buttonWidth }, buttonHeight);
+                if (MuControl.ButtonEx(ctx, "C", 0, (int)Options.AlignCenter).Flags.HasFlag(ResultFlags.Submit)) HandleKey("C");
+                if (MuControl.ButtonEx(ctx, ".", 0, (int)Options.AlignCenter).Flags.HasFlag(ResultFlags.Submit)) HandleKey(".");
+                if (MuControl.ButtonEx(ctx, "<-", 0, (int)Options.AlignCenter).Flags.HasFlag(ResultFlags.Submit)) HandleKey("<-");
+                if (MuControl.ButtonEx(ctx, "=", 0, (int)Options.AlignCenter).Flags.HasFlag(ResultFlags.Submit)) HandleKey("=");
+
+                MuControl.EndWindow(ctx);
             }
-            // End frame
+
             MicroUI.End(ctx);
 
-
-
-            // Print all commands in the command list
             int cmdIndex = 0;
             MuCommand? cmd = null;
             while ((cmd = MuCommandList.NextCommand(ctx, ref cmdIndex)) != null)
             {
-                                //Console.Write($"Command: {cmd.Type}");
                 switch (cmd)
                 {
                     case MuRectCommand rectCmd:
-                        //Console.WriteLine($" | Rect: ({rectCmd.Rect.X},{rectCmd.Rect.Y},{rectCmd.Rect.W},{rectCmd.Rect.H}) Color: {rectCmd.Color.R},{rectCmd.Color.G},{rectCmd.Color.B},{rectCmd.Color.A}");
                         Raylib.DrawRectangle(rectCmd.Rect.X, rectCmd.Rect.Y, rectCmd.Rect.W, rectCmd.Rect.H, new Color(rectCmd.Color.R, rectCmd.Color.G, rectCmd.Color.B, rectCmd.Color.A));
                         break;
                     case MuClipCommand clipCmd:
-                        //Console.Write($" | Clip: ({clipCmd.Rect.X},{clipCmd.Rect.Y},{clipCmd.Rect.W},{clipCmd.Rect.H})");
                         Raylib.BeginScissorMode(clipCmd.Rect.X, clipCmd.Rect.Y, clipCmd.Rect.W, clipCmd.Rect.H);
                         break;
-                    case MuJumpCommand jumpCmd:
-                        //Console.Write($" | Jump to: {jumpCmd.DestinationIndex}");
-                        break;
                     case MuTextCommand textCmd:
-                        Raylib.DrawText(textCmd.Text, textCmd.Position.X, textCmd.Position.Y, 10, new Color(textCmd.Color.R, textCmd.Color.G, textCmd.Color.B, textCmd.Color.A));
+                        Raylib.DrawText(textCmd.Text, textCmd.Position.X, textCmd.Position.Y, 20, new Color(textCmd.Color.R, textCmd.Color.G, textCmd.Color.B, textCmd.Color.A));
-                        //Console.Write($" | Text: '{textCmd.Text}' at ({textCmd.Position.X},{textCmd.Position.Y}) Color: {textCmd.Color.R},{textCmd.Color.G},{textCmd.Color.B},{textCmd.Color.A}");
-                        break;
-                    case MuIconCommand iconCmd:
-                        if (iconCmd.IconId == (int)IconType.Check)
-                        {
-                            // Draw a check mark
-                            int centerX = iconCmd.Rect.X + iconCmd.Rect.W / 2;
-                            int centerY = iconCmd.Rect.Y + iconCmd.Rect.H / 2;
-                            int size = Math.Min(iconCmd.Rect.W, iconCmd.Rect.H) / 3;
-                            
-                            // Draw check mark lines
-                            Raylib.DrawLine(
-                                centerX - size, centerY - size/2,
-                                centerX - size/3, centerY + size/2,
-                                new Color(iconCmd.Color.R, iconCmd.Color.G, iconCmd.Color.B, iconCmd.Color.A)
-                            );
-                            Raylib.DrawLine(
-                                centerX - size/3, centerY + size/2,
-                                centerX + size, centerY - size,
-                                new Color(iconCmd.Color.R, iconCmd.Color.G, iconCmd.Color.B, iconCmd.Color.A)
-                            );
-                        }
-                        else if (iconCmd.IconId == (int)IconType.Close)
-                        {
-                            // Draw an X for close
-                            int centerX = iconCmd.Rect.X + iconCmd.Rect.W / 2;
-                            int centerY = iconCmd.Rect.Y + iconCmd.Rect.H / 2;
-                            int size = Math.Min(iconCmd.Rect.W, iconCmd.Rect.H) / 3;
-                            
-                            // Draw X lines
-                            Raylib.DrawLine(
-                                centerX - size, centerY - size,
-                                centerX + size, centerY + size,
-                                new Color(iconCmd.Color.R, iconCmd.Color.G, iconCmd.Color.B, iconCmd.Color.A)
-                            );
-                            Raylib.DrawLine(
-                                centerX - size, centerY + size,
-                                centerX + size, centerY - size,
-                                new Color(iconCmd.Color.R, iconCmd.Color.G, iconCmd.Color.B, iconCmd.Color.A)
-                            );
-                        }
-                        else if (iconCmd.IconId == (int)IconType.Collapsed)
-                        {
-                            // Draw a right-pointing triangle for collapsed
-                            int centerX = iconCmd.Rect.X + iconCmd.Rect.W / 2;
-                            int centerY = iconCmd.Rect.Y + iconCmd.Rect.H / 2;
-                            int size = Math.Min(iconCmd.Rect.W, iconCmd.Rect.H) / 3;
-                            
-                            // Draw triangle pointing right
-                            Raylib.DrawTriangle(
-                                new Vector2(centerX - size/2, centerY - size),
-                                new Vector2(centerX + size/2, centerY),
-                                new Vector2(centerX - size/2, centerY + size),
-                                new Color(iconCmd.Color.R, iconCmd.Color.G, iconCmd.Color.B, iconCmd.Color.A)
-                            );
-                        }
-                        else if (iconCmd.IconId == (int)IconType.Expanded)
-                        {
-                            // Draw a down-pointing triangle for expanded
-                            int centerX = iconCmd.Rect.X + iconCmd.Rect.W / 2;
-                            int centerY = iconCmd.Rect.Y + iconCmd.Rect.H / 2;
-                            int size = Math.Min(iconCmd.Rect.W, iconCmd.Rect.H) / 3;
-                            
-                            // Draw triangle pointing down
-                            Raylib.DrawTriangle(
-                                new Vector2(centerX - size, centerY - size/2),
-                                new Vector2(centerX + size, centerY - size/2),
-                                new Vector2(centerX, centerY + size/2),
-                                new Color(iconCmd.Color.R, iconCmd.Color.G, iconCmd.Color.B, iconCmd.Color.A)
-                            );
-                        }
-                        else
-                        {
-                            // For unknown icons, draw a colored rectangle
-                            Raylib.DrawRectangle(iconCmd.Rect.X, iconCmd.Rect.Y, iconCmd.Rect.W, iconCmd.Rect.H, 
-                                new Color(iconCmd.Color.R, iconCmd.Color.G, iconCmd.Color.B, iconCmd.Color.A));
-                        }
                         break;
                 }
-
             }
 
             Raylib.EndDrawing();
-            //break;
         }
-
         Raylib.CloseWindow();
     }
 
-
+    private static void HandleKey(string key)
-    public static void Window(MuContext ctx, int x, int y, int index, ref bool isChecked, ref float sliderValue){
+    {
-        if(MuControl.BeginWindowEx(ctx, $"Test Window", new MuRect(x, y, 300, 200), 0)){
+        if (key == "<-")
-            // Manual two-column layout
+        {
-            MuLayoutUtil.LayoutRow(ctx, 2, new int[] { 120, 160 }, 0); // Adjust widths as needed
+            if (evaluated)
-
-            
-            // Left column (sliders/text)
             {
-                MuLayoutUtil.LayoutRow(ctx, 1, new int[] { 120 }, 0);
+                display = "0";
-                float test = 0;
+                currentInput = "";
-                //var sliderResult = MuControl.SliderEx(ctx, "main_slider", ref sliderValue, 0.0f, 100.0f, 1.0f, "F1", 0);
+                expression = "";
-                MuControl.SliderEx(ctx, "test_slider", ref test, 0.0f, 100.0f, 1.0f, "F1", 0);
+                evaluated = false;
-                // if ((sliderResult & ResultFlags.Change) != 0)
+            }
-                // {
+            else if (expression.Length > 0)
-                //     Console.WriteLine($"Slider value changed to: {sliderValue}");
+            {
-                // }
+                expression = expression[..^1];
-                MuControl.Text(ctx, "Other controls here...");
+                if (currentInput.Length > 0)
+                    currentInput = currentInput[..^1];
+                if (expression.Length == 0)
+                    display = "0";
+            }
+            return;
+        }
 
-                // Test TextboxRaw
+        if (char.IsDigit(key, 0) || key == ".")
-                var textboxRect = MuLayoutUtil.LayoutNext(ctx);
+        {
-                var textboxResult = MuControl.TextboxRaw(ctx, ref textboxValue, 12345, textboxRect, 0);
+            if (evaluated)
-                if ((textboxResult & ResultFlags.Change) != 0)
+            {
+                expression = "";
+                evaluated = false;
+            }
+            if (key == "." && currentInput.Contains(".")) return;
+            currentInput += key;
+            expression += key;
+            return;
+        }
+
+        if (key == "C")
+        {
+            display = "0";
+            currentInput = "";
+            expression = "";
+            evaluated = false;
+            return;
+        }
+
+        if (key == "=")
+        {
+            if (expression.Length > 0 && !IsOperator(expression[^1]) && expression[^1] != '(' && !evaluated)
+            {
+                try
                 {
-                    Console.WriteLine($"Textbox changed: {textboxValue}");
+                    var result = EvaluateExpression(expression);
+                    display = FormatResult(result);
+                    lastResult = result;
+                    lastOperation = expression;
+                    currentInput = "";
+                    expression = "";
+                    evaluated = true;
                 }
-
+                catch
-                // Test NumberEx (number textbox)
-                MuControl.Text(ctx, "Number control (Shift+Click to edit):");
-                var numberResult = MuControl.NumberEx(ctx, "test_number", ref sliderValue, 1.0f, "F2", 0);
-                if ((numberResult & ResultFlags.Change) != 0)
                 {
-                    Console.WriteLine($"Number changed to: {sliderValue}");
+                    display = "Error";
-                }
-
-                // Test second NumberEx (number textbox)
-                MuControl.Text(ctx, "Second number control (Shift+Click to edit):");
-                var secondNumberResult = MuControl.NumberEx(ctx, "test_number2", ref secondValue, 0.5f, "F2", 0);
-                if ((secondNumberResult & ResultFlags.Change) != 0)
-                {
-                    Console.WriteLine($"Second number changed to: {secondValue}");
                 }
             }
-
+            else if (evaluated && lastOperation.Length > 0)
-            // Right column (button grid)
             {
-                MuLayoutUtil.LayoutRow(ctx, 1, new int[] { 160 }, 0);
+                try
-                MuControl.Text(ctx, "4x4 Grid of Buttons with 'x' labels:");
-                for (int row = 0; row < 4; row++)
                 {
-                    MuLayoutUtil.LayoutRow(ctx, 4, new int[] { 25, 25, 25, 25 }, 0);
+                    var tokens = Tokenize(lastOperation);
-                    for (int col = 0; col < 4; col++)
+                    if (tokens.Count == 3 && tokens[1] is "+" or "-" or "*" or "/")
                     {
-                        MicroUI.PushId(ctx, System.Text.Encoding.UTF8.GetBytes($"grid_{row}_{col}"));
+                        var op = tokens[1];
-                        if (MuControl.ButtonEx(ctx, "x", 0, (int)Options.AlignCenter))
+                        var right = tokens[2];
+                        var newExpr = $"{lastResult} {op} {right}";
+                        var result = EvaluateExpression(newExpr);
+                        display = FormatResult(result);
+                        lastResult = result;
+                        expression = newExpr;
+                    }
+                    else
+                    {
+                        string op = "";
+                        string right = "";
+                        for (int i = tokens.Count - 1; i >= 0; i--)
                         {
-                            Console.WriteLine($"Button at ({row},{col}) clicked!");
+                            if (tokens[i] is "+" or "-" or "*" or "/")
+                            {
+                                op = tokens[i];
+                                right = lastResult.ToString();
+                                break;
+                            }
+                        }
+                        if (!string.IsNullOrEmpty(op))
+                        {
+                            var newExpr = $"{lastResult} {op} {right}";
+                            var result = EvaluateExpression(newExpr);
+                            display = FormatResult(result);
+                            lastResult = result;
+                            expression = newExpr;
                         }
-                        MicroUI.PopId(ctx);
                     }
                 }
+                catch
+                {
+                    display = "Error";
+                }
             }
+            return;
+        }
 
-         
+        if (key is "(" or ")")
-            MuControl.EndWindow(ctx);
+        {
+            if (evaluated)
+            {
+                expression = "";
+                evaluated = false;
+            }
+            expression += key;
+            currentInput = "";
+            return;
+        }
+
+        if (expression.Length == 0 && key == "-")
+        {
+            currentInput = "-";
+            expression = "-";
+            return;
+        }
+        if (expression.Length > 0 && !IsOperator(expression[^1]) && expression[^1] != '(')
+        {
+            expression += " " + key + " ";
+            currentInput = "";
+            evaluated = false;
         }
     }
+
+    private static bool IsOperator(char c) => c is '+' or '-' or '*' or '/';
+
+    private static double EvaluateExpression(string expr)
+    {
+        var tokens = Tokenize(expr);
+        int idx = 0;
+        var result = ParseExpression(tokens, ref idx);
+        if (idx < tokens.Count)
+            throw new Exception("Unexpected token: " + tokens[idx]);
+        return result;
+    }
+
+    private static List<string> Tokenize(string expr)
+    {
+        var tokens = new List<string>();
+        var current = "";
+        foreach (var c in expr)
+        {
+            if (char.IsDigit(c) || c == '.')
+                current += c;
+            else if (c is '+' or '-' or '*' or '/' or '(' or ')')
+            {
+                if (current.Length > 0)
+                {
+                    tokens.Add(current);
+                    current = "";
+                }
+                tokens.Add(c.ToString());
+            }
+            else if (c == ' ')
+            {
+                if (current.Length > 0)
+                {
+                    tokens.Add(current);
+                    current = "";
+                }
+            }
+        }
+        if (current.Length > 0)
+            tokens.Add(current);
+        return tokens;
+    }
+
+    private static double ParseExpression(List<string> tokens, ref int idx)
+    {
+        var left = ParseTerm(tokens, ref idx);
+        while (idx < tokens.Count && (tokens[idx] == "+" || tokens[idx] == "-"))
+        {
+            var op = tokens[idx++];
+            var right = ParseTerm(tokens, ref idx);
+            left = op == "+" ? left + right : left - right;
+        }
+        return left;
+    }
+
+    private static double ParseTerm(List<string> tokens, ref int idx)
+    {
+        var left = ParseFactor(tokens, ref idx);
+        while (idx < tokens.Count && (tokens[idx] == "*" || tokens[idx] == "/"))
+        {
+            var op = tokens[idx++];
+            var right = ParseFactor(tokens, ref idx);
+            if (op == "*") left *= right;
+            else if (op == "/" && right != 0) left /= right;
+            else throw new DivideByZeroException();
+        }
+        return left;
+    }
+
+    private static double ParseFactor(List<string> tokens, ref int idx)
+    {
+        if (idx >= tokens.Count)
+            throw new Exception("Unexpected end of expression");
+        var token = tokens[idx++];
+        if (token == "(")
+        {
+            var result = ParseExpression(tokens, ref idx);
+            if (idx >= tokens.Count || tokens[idx] != ")")
+                throw new Exception("Missing closing parenthesis");
+            idx++;
+            return result;
+        }
+        if (double.TryParse(token, out double number))
+            return number;
+        throw new Exception($"Invalid token: {token}");
+    }
+
+    private static string FormatResult(double value)
+    {
+        value = Math.Round(value, 10);
+        if (Math.Abs(value - Math.Round(value)) < 1e-10)
+            value = Math.Round(value);
+        var s = value.ToString("G15");
+        if (s.Contains("."))
+        {
+            s = s.TrimEnd('0');
+            if (s.EndsWith("."))
+                s = s.TrimEnd('.');
+        }
+        return s;
+    }
 }