More little things to the parser

Functions/Compare.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace SuperBASIC.Functions
+{
+	class Compare : IFunction
+	{
+		float IFunction.Apply(List<BasicNumber> arguments)
+		{
+			return arguments[0] == arguments[1] ? 1 : 0;
+		}
+	}
+}

Functions/Constants.cs

@@ -0,0 +1,21 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace SuperBASIC.Functions
+{
+	class Pi : IFunction
+	{
+		float IFunction.Apply(List<BasicNumber> arguments)
+		{
+			return (float)Math.PI;
+		}
+	}
+	class Euler : IFunction
+	{
+		float IFunction.Apply(List<BasicNumber> arguments)
+		{
+			return (float)Math.E;
+		}
+	}
+}

Parser.cs

@@ -62,7 +62,7 @@ namespace SuperBASIC
 				if(!library.nameResolution.ContainsKey(components[0]))
 				{
 					int lineIndex = 0;
-					foreach (int cnt in lineSpans.GetRange(0, idx)) lineIndex += cnt;
+					foreach (int cnt in lineSpans.GetRange(0, idx+1)) lineIndex += cnt;
 					throw new ParseException($"Unknown operation \"{components[0]}\"\n\tat line {lineIndex}");
 				}
 
@@ -72,7 +72,7 @@ namespace SuperBASIC
 				if(arity != components.Length-1)
 				{
 					int lineIndex = 0;
-					foreach (int cnt in lineSpans.GetRange(0, idx)) lineIndex += cnt;
+					foreach (int cnt in lineSpans.GetRange(0, idx+1)) lineIndex += cnt;
 					throw new ParseException($"Operation {components[0]} was provided with the wrong number of arguments\n\tExpected {arity} found {components.Length-1}\n\tat line {lineIndex}");
 				}
 
@@ -81,7 +81,16 @@ namespace SuperBASIC
 				{
 					if (elem != "$")
 					{
-						c.bytecode.Add(new BasicNumber(runtime, float.Parse(elem)));
+						try
+						{
+							float v = float.Parse(elem);
+							c.bytecode.Add(new BasicNumber(runtime, v));
+						}
+						catch(Exception) {
+							int lineIndex = 0;
+							foreach (int cnt in lineSpans.GetRange(0, idx+1)) lineIndex += cnt;
+							throw new ParseException($"Cannot parse {elem} as argument\n\tExpected floating point number or '$'\n\tat line {lineIndex}");
+						}
 					}
 					else
 					{

Program.cs

@@ -7,12 +7,21 @@ namespace SuperBASIC
 	{
 		static void Main(string[] args)
 		{
-			Library lib = new Library();
-			lib.AddFunction(new Functions.Print(), 1, "PRINT");
-			lib.AddFunction(new Functions.Multiply(), 2, "MULTIPLY");
-			Runtime r = new Runtime(lib);
-			r.OpenFile(Directory.GetCurrentDirectory() + "\\Test.basic");
-			r.Run();
+			try
+			{
+				Library lib = new Library();
+				lib.AddFunction(new Functions.Print(), 1, "PRINT");
+				lib.AddFunction(new Functions.Multiply(), 2, "MULTIPLY");
+				lib.AddFunction(new Functions.Compare(), 2, "COMPARE");
+				lib.AddFunction(new Functions.Pi(), 0, "PI");
+				lib.AddFunction(new Functions.Euler(), 0, "EULER");
+				Runtime r = new Runtime(lib);
+				r.OpenFile(Directory.GetCurrentDirectory() + "\\Test.basic");
+				r.Run();
+			} catch (Parser.ParseException e)
+			{
+				Console.WriteLine($"Parsing failed:\n{e}");
+			}
 		}
 	}
 }

Test.basic

@@ -1,2 +1,4 @@
-MULTIPLY 2 3
+EULER
+MULTIPLY $ $
+COMPARE $ 7.3890557
 PRINT $