LaunchArgumentParser.HelpMessageHeader

DTLib/Console/LaunchArgumentParser.cs

@@ -2,32 +2,123 @@ namespace DTLib.Console;
 
 public class LaunchArgumentParser
 {
+    public string HelpMessageHeader = "USAGE:";
     public bool IsAllowedNoArguments;
     
     private readonly Dictionary<string, LaunchArgument> argDict = new();
     private readonly List<LaunchArgument> argList = new();
 
-    public class ExitAfterHelpException : Exception
+    public LaunchArgumentParser() 
     {
-        internal ExitAfterHelpException() : base("your program can use this exception to exit after displaying help message")
+        var help = new LaunchArgument(new[] { "h", "help" },
-        { }
+            "shows help message", HelpHandler);
+        Add(help);
+        var helpArg = new LaunchArgument(new[] { "ha", "helparg" },
+            "shows help message for specific argument",
+            HelpArgHandler, "argument");
+        Add(helpArg);
     }
+    public LaunchArgumentParser(ICollection<LaunchArgument> arguments) : this() => WithArgs(arguments);
+    public LaunchArgumentParser(params LaunchArgument[] arguments) : this() => WithArgs(arguments);
+
+    public LaunchArgumentParser WithArgs(IEnumerable<LaunchArgument> args)
+    {
+        foreach (var arg in args)
+            Add(arg);
+        return this;
+    }
+    
+    public LaunchArgumentParser WithArgs(params LaunchArgument[] args)
+    {
+        foreach (var arg in args)
+            Add(arg);
+        return this;
+    }
+
+    public LaunchArgumentParser WithHelpMessageHeader(string header)
+    {
+        HelpMessageHeader = header;
+        return this;
+    }
+    
+    public LaunchArgumentParser AllowNoArguments()
+    {
+        IsAllowedNoArguments = true;
+        return this;
+    }
+
     
     public string CreateHelpMessage()
     {
-        StringBuilder b = new();
+        StringBuilder b = new(HelpMessageHeader);
-        foreach (var arg in argList) 
+        foreach (var arg in argList)
-            arg.AppendHelpInfo(b).Append('\n');
+        {
-        b.Remove(b.Length-1, 1);
+            b.Append('\n');
+            arg.AppendHelpInfo(b);
+        }
         return b.ToString();
     }
+
     public string CreateHelpArgMessage(string argAlias)
     {
         StringBuilder b = new();
-        var arg = Parse(argAlias);
+        var arg = ParseArg(argAlias);
         arg.AppendHelpInfo(b);
         return b.ToString();
     }
+
+    public void Add(LaunchArgument arg)
+    {
+        argList.Add(arg);
+        foreach (string alias in arg.Aliases)
+            argDict.Add(alias, arg);
+    }
+
+    public LaunchArgument ParseArg(string argAlias)
+    {
+        // different argument providing patterns
+        if (!argDict.TryGetValue(argAlias, out var arg) && // arg
+            !(argAlias.StartsWith("--") && argDict.TryGetValue(argAlias.Substring(2), out arg)) && // --arg
+            !(argAlias.StartsWith('-') && argDict.TryGetValue(argAlias.Substring(1), out arg)) && // -arg
+            !(argAlias.StartsWith('/') && argDict.TryGetValue(argAlias.Substring(1), out arg))) // /arg
+            throw new Exception($"invalid argument: {argAlias}\n{CreateHelpMessage()}");
+
+        return arg;
+    }
+
+    /// <param name="args">program launch args</param>
+    /// <exception cref="Exception">argument {args[i]} should have a parameter after it</exception>
+    /// <exception cref="NullReferenceException">argument hasn't got any handlers</exception>
+    /// <exception cref="ExitAfterHelpException">happens after help message is displayed</exception>
+    public void ParseAndHandle(string[] args)
+    {
+        // show help message and throw ExitAfterHelpException
+        if (args.Length == 0 && !IsAllowedNoArguments)
+            HelpHandler();
+
+        List<LaunchArgument> execQueue = new();
+
+        for (int i = 0; i < args.Length; i++)
+        {
+            var arg = ParseArg(args[i]);
+            for (int j = 0; j < arg.Params.Length; j++)
+            {
+                if (++i >= args.Length)
+                    throw new Exception(
+                        $"argument '{arg.Aliases[0]}' should have parameter '{arg.Params[j]}' after it");
+                arg.Params[j].Value = args[i];
+            }
+
+            execQueue.Add(arg);
+        }
+
+        // ascending sort by priority
+        execQueue.Sort((a0, a1) => a0.Priority - a1.Priority);
+        // finally executing handlers
+        foreach (var a in execQueue)
+            a.Handle();
+    }
+
     private void HelpHandler()
     {
         System.Console.WriteLine(CreateHelpMessage());
@@ -40,83 +131,11 @@ public class LaunchArgumentParser
         throw new ExitAfterHelpException();
     }
 
-
+    public class ExitAfterHelpException : Exception
-    public LaunchArgumentParser()
     {
-        var help = new LaunchArgument(new[] { "h", "help" }, 
+        public ExitAfterHelpException()
-            "shows help message", HelpHandler);
+            : base("your program can use this exception to exit after displaying help message")
-        Add(help);
-        var helpArg = new LaunchArgument( new[]{ "ha", "helparg" }, 
-            "shows help message for particular argument", 
-            HelpArgHandler, "argAlias");
-        Add(helpArg);
-    }
-
-    public LaunchArgumentParser AllowNoArguments()
-    {
-        IsAllowedNoArguments = true;
-        return this;
-    }
-
-    public LaunchArgumentParser(ICollection<LaunchArgument> arguments) : this()
-    {
-        foreach (var arg in arguments) 
-            Add(arg);
-    }
-    public LaunchArgumentParser(params LaunchArgument[] arguments) : this()
-    {
-        foreach (var arg in arguments)
-            Add(arg);
-    }
-
-    public void Add(LaunchArgument arg)
-    {
-        argList.Add(arg);
-        foreach (string alias in arg.Aliases)
-            argDict.Add(alias, arg);
-    }
-    
-    public LaunchArgument Parse(string argAlias)
-    {
-        // different argument providing patterns
-        if (!argDict.TryGetValue(argAlias, out var arg) &&    // arg
-            !(argAlias.StartsWith("--") && argDict.TryGetValue(argAlias.Substring(2), out arg)) && // --arg
-            !(argAlias.StartsWith('-') && argDict.TryGetValue(argAlias.Substring(1), out arg)) &&  // -arg
-            !(argAlias.StartsWith('/') && argDict.TryGetValue(argAlias.Substring(1), out arg)))    // /arg
-            throw new Exception($"invalid argument: {argAlias}\n{CreateHelpMessage()}");
-        
-        return arg;
-    }
-    
-    /// <param name="args">program launch args</param>
-    /// <exception cref="Exception">argument {args[i]} should have a parameter after it</exception>
-    /// <exception cref="NullReferenceException">argument hasn't got any handlers</exception>
-    /// <exception cref="ExitAfterHelpException">happens after help message is displayed</exception>
-    public void ParseAndHandle(string[] args)
-    {
-        // show help message and throw ExitAfterHelpException
-        if (args.Length == 0 && !IsAllowedNoArguments) 
-            HelpHandler();
-
-        List<LaunchArgument> execQueue = new();
-        
-        for (int i = 0; i < args.Length; i++)
         {
-            LaunchArgument arg = Parse(args[i]);
-            for (int j = 0; j < arg.Params.Length; j++)
-            {
-                if (++i >= args.Length)
-                    throw new Exception($"argument '{arg.Aliases[0]}' should have parameter '{arg.Params[j]}' after it");
-                arg.Params[j].Value = args[i];
-            }
-            
-            execQueue.Add(arg);
         }
-        
-        // ascending sort by priority
-        execQueue.Sort((a0, a1) => a0.Priority-a1.Priority);
-        // finally executing handlers
-        foreach (var a in execQueue) 
-            a.Handle();
     }
 }