Reworked diagnostics, saves line positions in memory, instead of calculating later.

Upsilon/BaseTypes/ScriptFunction/ScriptMethodInfoFunction.cs

@@ -107,11 +107,9 @@ namespace Upsilon.BaseTypes.ScriptFunction
                     // if we haven't found a method, we throw an exception
                     if (method == null)
                     {
-                        var (i, pos) = diagnostics.ScriptString.GetLinePosition(span.Start);
-                        var line = diagnostics.ScriptString.GetLine(i);
                         throw new ScriptRuntimeException(
                             $"Can't find method {_method.Name} with parameter types {string.Join(", ", convertedTypes.Select(x => x.Name))} on type {_object.GetType().Name}",
-                            i, pos, line);
+                            span, diagnostics.ScriptString.GetSpan(span));
                     }
                     // get the method parameters
                     var parameters = method.GetParameters();

Upsilon/BaseTypes/UserData/ListUserData.cs

@@ -51,11 +51,9 @@ namespace Upsilon.BaseTypes.UserData
             }
             else
             {
-                var (i, pos) = diagnostics.ScriptString.GetLinePosition(span.Start);
-                var line = diagnostics.ScriptString.GetLine(i);
                 throw new ScriptRuntimeException(
                     $"Tried indexing a CSharp list with a value that's not an integer. Value: {scriptIndex.ToCSharpObject()}",
-                    i, pos, line);
+                    span, diagnostics.ScriptString.GetSpan(span));
             }
 
             index--;

Upsilon/Binder/BoundExpressions/BoundBinaryExpression.cs

@@ -17,18 +17,18 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundBinaryExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int line, int character)
         {
-            if (characterPosition >= LeftExpression.Span.Start && characterPosition <= LeftExpression.Span.End)
+            if (LeftExpression.Span.Contains(line, character))
             {
-                foreach (var exp in LeftExpression.GetNodeAtPosition(characterPosition))
+                foreach (var exp in LeftExpression.GetNodeAtPosition(line, character))
                 {
                     yield return exp;
                 }
             }
-            if (characterPosition >= RightExpression.Span.Start && characterPosition <= RightExpression.Span.End)
+            if (RightExpression.Span.Contains(line, character))
             {
-                foreach (var exp in RightExpression.GetNodeAtPosition(characterPosition))
+                foreach (var exp in RightExpression.GetNodeAtPosition(line, character))
                 {
                     yield return exp;
                 }

Upsilon/Binder/BoundExpressions/BoundFunctionCallExpression.cs

@@ -19,20 +19,25 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundFunctionCallExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int line, int character)
         {
-            if (characterPosition >= Identifier.Span.Start && characterPosition <= Identifier.Span.End)
+            if (Identifier.Span.Contains(line, character))
             {
-                foreach (var exp in Identifier.GetNodeAtPosition(characterPosition))
+                foreach (var exp in Identifier.GetNodeAtPosition(line, character))
                 {
                     yield return exp;
                 }
+
             }
             foreach (var parameter in Parameters)
             {
-                if (characterPosition >= parameter.Span.Start && characterPosition <= parameter.Span.End)
+                if (parameter.Span.Contains(line, character))
                 {
-                    foreach (var boundNode in parameter.GetNodeAtPosition(characterPosition)) yield return boundNode;
+                    foreach (var exp in parameter.GetNodeAtPosition(line, character))
+                    {
+                        yield return exp;
+                    }
+
                 }
             }
             yield return this;

Upsilon/Binder/BoundExpressions/BoundFunctionExpression.cs

@@ -20,17 +20,21 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundFunctionExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
             foreach (var parameter in Parameters)
             {
-                if (characterPosition >= parameter.Span.Start && characterPosition <= parameter.Span.End)
+                if (parameter.Span.Contains(linePosition, characterPosition))
-                    foreach (var boundNode in parameter.GetNodeAtPosition(characterPosition))
+                {
+                    foreach (var boundNode in parameter.GetNodeAtPosition(linePosition, characterPosition))
                         yield return boundNode;
+                }
             }
-            if (characterPosition >= Block.Span.Start && characterPosition <= Block.Span.End)
+            if (Block.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Block.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Block.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
+            }
             yield return this;
         }
 

Upsilon/Binder/BoundExpressions/BoundIndexExpression.cs

@@ -18,16 +18,18 @@ namespace Upsilon.Binder
         public BoundExpression Index { get; }
 
         public override BoundKind Kind => BoundKind.BoundIndexExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Identifier.Span.Start && characterPosition <= Identifier.Span.End)
+            if (Identifier.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Identifier.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Identifier.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
-            if (characterPosition >= Index.Span.Start && characterPosition <= Index.Span.End)
+            if (Index.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Index.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Index.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
             yield return this;
         }
 
@@ -47,12 +49,15 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundFullstopIndexExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Expression.Span.Start && characterPosition <= Expression.Span.End)
+            if (Expression.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Expression.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Expression.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
 
+            }
+
             yield return this;
         }
 

Upsilon/Binder/BoundExpressions/BoundLiteralExpression.cs

@@ -12,7 +12,7 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundLiteralExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int line, int character)
         {
             yield return this;
         }

Upsilon/Binder/BoundExpressions/BoundTableExpression.cs

@@ -17,16 +17,16 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundTableExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
             foreach (var statement in Statements)
             {
-                if (characterPosition >= statement.Span.Start && characterPosition <= statement.Span.End)
+                if (statement.Span.Contains(linePosition, characterPosition))
-                    foreach (var boundNode in statement.GetNodeAtPosition(characterPosition))
+                {
-                        yield return boundNode;
+                    yield return statement;
+                }
             }
             yield return this;
-
         }
 
         public override Type Type => Type.Table;

Upsilon/Binder/BoundExpressions/BoundUnaryExpression.cs

@@ -7,12 +7,13 @@ namespace Upsilon.Binder
     public class BoundUnaryExpression : BoundExpression
     {
         public override BoundKind Kind => BoundKind.BoundUnaryExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= InExpression.Span.Start && characterPosition <= InExpression.Span.End)
+            if (InExpression.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in InExpression.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in InExpression.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
             yield return this;
         }
 

Upsilon/Binder/BoundExpressions/BoundVariableExpression.cs

@@ -14,7 +14,7 @@ namespace Upsilon.Binder
 
         public BoundVariableSymbol Variable { get; }
         public override BoundKind Kind => BoundKind.VariableExpression;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
             yield return Variable;
         }

Upsilon/Binder/BoundNode.cs

@@ -13,6 +13,6 @@ namespace Upsilon.Binder
         public abstract BoundKind Kind { get; }
         public TextSpan Span { get; }
 
-        public abstract IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition);
+        public abstract IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition);
     }
 }

Upsilon/Binder/BoundStatements/BoundBlockStatement.cs

@@ -13,13 +13,17 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundBlockStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
             foreach (var statement in Statements)
             {
-                if (characterPosition >= statement.Span.Start && characterPosition <= statement.Span.End)
+                if (statement.Span.Contains(linePosition, characterPosition))
-                    foreach (var boundNode in statement.GetNodeAtPosition(characterPosition))
+                {
-                        yield return boundNode;
+                    foreach (var node in statement.GetNodeAtPosition(linePosition, characterPosition))
+                    {
+                        yield return node;
+                    }
+                }
             }
             yield return this;
         }

Upsilon/Binder/BoundStatements/BoundBreakStatement.cs

@@ -10,11 +10,9 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundBreakStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Span.Start && characterPosition <= Span.End)
+            yield return this;
-                yield return this;
-            yield return null;
         }
     }
 }

Upsilon/Binder/BoundStatements/BoundExpressionStatement.cs

@@ -7,13 +7,11 @@ namespace Upsilon.Binder
     {
         public BoundExpression Expression { get; }
         public override BoundKind Kind => BoundKind.BoundExpressionStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Span.Start && characterPosition <= Span.End)
+            foreach (var boundNode in Expression.GetNodeAtPosition(linePosition, characterPosition))
-                foreach (var boundNode in Expression.GetNodeAtPosition(characterPosition))
+                yield return boundNode;
-                    yield return boundNode;
 
-            yield return this;
         }
 
         public BoundExpressionStatement(BoundExpression expression, TextSpan span):base(span)

Upsilon/Binder/BoundStatements/BoundFunctionAssignmentStatement.cs

@@ -16,10 +16,10 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundFunctionAssignmentStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Func.Span.Start && characterPosition <= Func.Span.End)
+            if (Func.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Func.GetNodeAtPosition(characterPosition))
+                foreach (var boundNode in Func.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
 
             yield return this;

Upsilon/Binder/BoundStatements/BoundGenericForStatement.cs

@@ -20,16 +20,18 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundGenericForStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= BoundEnumerableExpression.Span.Start && characterPosition <= BoundEnumerableExpression.Span.End)
+            if (BoundEnumerableExpression.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in BoundEnumerableExpression.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in BoundEnumerableExpression.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
-            if (characterPosition >= Block.Span.Start && characterPosition <= Block.Span.End)
+            if (Block.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Block.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Block.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
             yield return this;
         }
     }

Upsilon/Binder/BoundStatements/BoundIfStatement.cs

@@ -25,24 +25,28 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundIfStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Condition.Span.Start && characterPosition <= Condition.Span.End)
+            if (Condition.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Condition.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Condition.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
-            if (characterPosition >= Block.Span.Start && characterPosition <= Block.Span.End)
+            if (Block.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Block.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Block.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
-            if (NextElseIf != null && characterPosition >= NextElseIf.Span.Start && characterPosition <= NextElseIf.Span.End)
+            if (NextElseIf != null && NextElseIf.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in NextElseIf.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in NextElseIf.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
-            if (ElseStatement != null && characterPosition >= ElseStatement.Span.Start && characterPosition <= ElseStatement.Span.End)
+            if (ElseStatement != null && ElseStatement.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in ElseStatement.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in ElseStatement.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
             yield return this;
         }
 
@@ -62,12 +66,13 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundElseStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (Block != null && characterPosition >= Block.Span.Start && characterPosition <= Block.Span.End)
+            if (Block.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Block.GetNodeAtPosition(characterPosition))
+            {
+                foreach (var boundNode in Block.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            }
             yield return this;
         }
     }

Upsilon/Binder/BoundStatements/BoundMultiAssignmentStatement.cs

@@ -18,14 +18,13 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundMultiAssignmentStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Assignment.Span.Start && characterPosition <= Assignment.Span.End)
+            if (Assignment.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Assignment.GetNodeAtPosition(characterPosition))
+                foreach (var boundNode in Assignment.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
 
             yield return this;
-
         }
     }
 }

Upsilon/Binder/BoundStatements/BoundNumericForStatement.cs

@@ -23,26 +23,21 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundNumericForStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= BoundStart.Span.Start && characterPosition <= BoundStart.Span.End)
+            if (BoundStart.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in BoundStart.GetNodeAtPosition(characterPosition))
+                foreach (var boundNode in BoundStart.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            if (BoundStop.Span.Contains(linePosition, characterPosition))
-            if (characterPosition >= BoundStop.Span.Start && characterPosition <= BoundStop.Span.End)
+                foreach (var boundNode in BoundStop.GetNodeAtPosition(linePosition, characterPosition))
-                foreach (var boundNode in BoundStop.GetNodeAtPosition(characterPosition))
                     yield return boundNode;
-
+            if (BoundStep.Span.Contains(linePosition, characterPosition))
-            if (characterPosition >= BoundStep.Span.Start && characterPosition <= BoundStep.Span.End)
+                foreach (var boundNode in BoundStep.GetNodeAtPosition(linePosition, characterPosition))
-                foreach (var boundNode in BoundStep.GetNodeAtPosition(characterPosition))
                     yield return boundNode;
-
+            if (Block.Span.Contains(linePosition, characterPosition))
-            if (characterPosition >= Block.Span.Start && characterPosition <= Block.Span.End)
+                foreach (var boundNode in Block.GetNodeAtPosition(linePosition, characterPosition))
-                foreach (var boundNode in Block.GetNodeAtPosition(characterPosition))
                     yield return boundNode;
-
             yield return this;
-
         }
     }
 }

Upsilon/Binder/BoundStatements/BoundReturnStatement.cs

@@ -12,12 +12,11 @@ namespace Upsilon.Binder
 
         public BoundExpression Expression { get; }
         public override BoundKind Kind => BoundKind.BoundReturnStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Expression.Span.Start && characterPosition <= Expression.Span.End)
+            if (Expression.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Expression.GetNodeAtPosition(characterPosition))
+                foreach (var boundNode in Expression.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
             yield return this;
         }
     }

Upsilon/Binder/BoundStatements/BoundScript.cs

@@ -7,7 +7,7 @@ namespace Upsilon.Binder
     public class BoundScript : BoundStatement
     {
         public Script Script { get; }
-        
+
         public BoundScript(BoundBlockStatement statement, TextSpan span, BoundScope scope, string fileName, Script script) : base(span)
         {
             Statement = statement;
@@ -18,9 +18,9 @@ namespace Upsilon.Binder
 
         public string FileName { get; set; }
         public override BoundKind Kind => BoundKind.BoundScript;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            foreach (var boundNode in Statement.GetNodeAtPosition(characterPosition)) yield return boundNode;
+            foreach (var boundNode in Statement.GetNodeAtPosition(linePosition, characterPosition)) yield return boundNode;
         }
 
         public BoundBlockStatement Statement { get; }

Upsilon/Binder/BoundStatements/BoundTableAssigmentStatement.cs

@@ -16,18 +16,15 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundTableAssigmentStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= TableIndexExpression.Span.Start && characterPosition <= TableIndexExpression.Span.End)
+            if (TableIndexExpression.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in TableIndexExpression.GetNodeAtPosition(characterPosition))
+                foreach (var boundNode in TableIndexExpression.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            if (Value.Span.Contains(linePosition, characterPosition))
-            if (characterPosition >= Value.Span.Start && characterPosition <= Value.Span.End)
+                foreach (var boundNode in Value.GetNodeAtPosition(linePosition, characterPosition))
-                foreach (var boundNode in Value.GetNodeAtPosition(characterPosition))
                     yield return boundNode;
-
             yield return this;
-
         }
     }
 }

Upsilon/Binder/BoundStatements/BoundVariableAssignment.cs

@@ -18,16 +18,15 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundAssignmentStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Variable.Span.Start && characterPosition <= Variable.Span.End)
+            if (Variable.Span.Contains(linePosition, characterPosition))
                 yield return Variable;
-            if (characterPosition >= BoundExpression.Span.Start && characterPosition <= BoundExpression.Span.End)
+            if (BoundExpression.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in BoundExpression.GetNodeAtPosition(characterPosition))
+                foreach (var boundNode in BoundExpression.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
 
             yield return this;
-
         }
     }
 }

Upsilon/Binder/BoundStatements/BoundWhileStatement.cs

@@ -17,16 +17,14 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundWhileStatement;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
-            if (characterPosition >= Condition.Span.Start && characterPosition <= Condition.Span.End)
+            if (Condition.Span.Contains(linePosition, characterPosition))
-                foreach (var boundNode in Condition.GetNodeAtPosition(characterPosition))
+                foreach (var boundNode in Condition.GetNodeAtPosition(linePosition, characterPosition))
                     yield return boundNode;
-
+            if (Block.Span.Contains(linePosition, characterPosition))
-            if (characterPosition >= Block.Span.Start && characterPosition <= Block.Span.End)
+                foreach (var boundNode in Block.GetNodeAtPosition(linePosition, characterPosition))
-                foreach (var boundNode in Block.GetNodeAtPosition(characterPosition))
                     yield return boundNode;
-
             yield return this;
         }
     }

Upsilon/Binder/BoundStatements/UnboundFunctionExpression.cs

@@ -19,19 +19,19 @@ namespace Upsilon.Binder
 
         public BlockStatementSyntax UnboundBlock { get; }
 
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int linePosition, int characterPosition)
         {
             foreach (var parameter in Parameters)
             {
-                if (characterPosition >= parameter.Span.Start && characterPosition <= parameter.Span.End)
+                if (parameter.Span.Contains(linePosition, characterPosition))
-                    foreach (var boundNode in parameter.GetNodeAtPosition(characterPosition))
+                    foreach (var boundNode in parameter.GetNodeAtPosition(linePosition, characterPosition))
                         yield return boundNode;
             }
 
             if (Block != null)
             {
-                if (characterPosition >= Block.Span.Start && characterPosition <= Block.Span.End)
+                if (Block.Span.Contains(linePosition, characterPosition))
-                    foreach (var boundNode in Block.GetNodeAtPosition(characterPosition))
+                    foreach (var boundNode in Block.GetNodeAtPosition(linePosition, characterPosition))
                         yield return boundNode;
             }
             yield return this;

Upsilon/Binder/BoundVariableSymbol.cs

@@ -17,7 +17,7 @@ namespace Upsilon.Binder
 
         public bool IsCreation { get; }
         public override BoundKind Kind => BoundKind.BoundVariableSymbol;
-        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition)
+        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition, int i)
         {
             yield return this;
         }

Upsilon/Diagnostics.cs

@@ -33,9 +33,8 @@ namespace Upsilon
         {
             if (ThrowsOnError)
             {
-                var linePos = ScriptString.GetLinePosition(location.Start);
+                var text = ScriptString.GetSpan(location);
-                var line = ScriptString.GetLine(linePos.Line);
+                throw new ParseException(FileName, message, location.StartLine, location.StartPosition, text);
-                throw new ParseException(FileName, message, linePos.Line, linePos.Pos, line);
             }
             Log(DiagnosticLevel.Error, message, location);
         }
@@ -122,39 +121,24 @@ namespace Upsilon
             Span = span;
         }
 
-        public (int Position, int PositionOnLine) GetStartLine()
-        {
-            return Diagnostics.ScriptString.GetLinePosition(Span.Start);
-        }
-
-        public (int Position, int PositionOnLine) GetEndLine()
-        {
-            return Diagnostics.ScriptString.GetLinePosition(Span.End);
-        }
-
-
         public override string ToString()
         {
-            var linePos = Diagnostics.ScriptString.GetLinePosition(Span.Start);
+            return $"{Message} at ({Span.StartLine}, {Span.StartPosition})\n{Diagnostics.ScriptString.GetSpan(Span)}";
-            return $"{Message} at ({linePos.Line}, {linePos.Pos})\n{Diagnostics.ScriptString.GetSpan(Span)}";
         }
 
         public string GetDiagnosticPosition()
         {
-            var linePos = Diagnostics.ScriptString.GetLinePosition(Span.Start);
+            return $"({Span.StartLine},{Span.StartPosition})";
-            return $"({linePos.Line},{linePos.Pos})";
         }
 
         public string LineBeforeError()
         {
-            var linePos = Diagnostics.ScriptString.GetLinePosition(Span.Start);
+            return Diagnostics.ScriptString.GetSpan(Span.StartLine, 0, Span.StartLine, Span.StartPosition);
-            var lineIndex = Diagnostics.ScriptString.GetLineStartPos(linePos.Line);
-            return Diagnostics.ScriptString.GetSpan(lineIndex, linePos.Pos);
         }
 
         public string BeforeError(int i = 5)
         {
-            return Diagnostics.ScriptString.GetSpan(Span.Start - i, i);
+            return Diagnostics.ScriptString.GetSpan(Span.StartLine, Span.StartPosition - i, Span.StartLine, Span.StartPosition);
         }
 
         public string AtError()
@@ -164,15 +148,12 @@ namespace Upsilon
 
         public string LineAfterError()
         {
-            var linePos   = Diagnostics.ScriptString.GetLinePosition(Span.Start);
+            return Diagnostics.ScriptString.GetSpan(Span.EndLine, Span.EndPosition, Span.EndLine, 10000);
-            var lineInfo = Diagnostics.ScriptString.GetLineInfo(linePos.Line);
-
-            return Diagnostics.ScriptString.GetSpan(Span.End, lineInfo.End - Span.End);
         }
 
         public string AfterError(int i = 5)
         {
-            return Diagnostics.ScriptString.GetSpan(Span.Start + Span.Length, i);
+            return Diagnostics.ScriptString.GetSpan(Span.EndLine, Span.EndPosition, Span.EndLine, Span.EndPosition + i);
         }
 
     }

Upsilon/Evaluator/Debugging/DebugFile.cs

@@ -10,5 +10,6 @@ namespace Upsilon.Evaluator.Debugging
     public class Breakpoint
     {
         public int Line { get; set; }
+        public int Position { get; set; }
     }
 }

Upsilon/Evaluator/Evaluator.cs

@@ -67,8 +67,7 @@ namespace Upsilon.Evaluator
                 {
                     foreach (var breakpoint in file.Breakpoints)
                     {
-                        var lineStart = _script.ScriptString.GetLineInfo(breakpoint.Line).Start;
+                        var debugStatement = e.GetBottomStatementAtPosition(breakpoint.Line, breakpoint.Position);
-                        var debugStatement = e.GetBottomStatementAtPosition(lineStart);
                         debugStatement.HasBreakpoint = true;
                     }
                 }
@@ -436,9 +435,7 @@ namespace Upsilon.Evaluator
 
         private void ThrowException(string message, TextSpan location)
         {
-            var (i, pos) = _script.ScriptString.GetLinePosition(location.Start);
+            throw new ScriptRuntimeException(message, location, _diagnostics.ScriptString.GetSpan(location));
-            var line    = _script.ScriptString.GetLine(i);
-            throw new ScriptRuntimeException(message, i, pos, line);
         }
 
         private void EvaluateAssignmentStatement(BoundVariableAssignment e)

Upsilon/Exceptions/ScriptRuntimeException.cs

@@ -1,4 +1,5 @@
 using System;
+using Upsilon.Text;
 
 namespace Upsilon.Exceptions
 {
@@ -9,11 +10,11 @@ namespace Upsilon.Exceptions
         public int    Character    { get; }
         public string ErrorLine    { get; }
 
-        public ScriptRuntimeException(string errorMessage, int line, int character, string errorLine)
+        public ScriptRuntimeException(string errorMessage, TextSpan position, string errorLine)
         {
             ErrorMessage = errorMessage;
-            Line         = line;
+            Line         = position.StartLine;
-            Character    = character;
+            Character    = position.StartPosition;
             ErrorLine    = errorLine;
         }
 

Upsilon/Parser/ExpressionSyntax/BinaryExpressionSyntax.cs

@@ -10,7 +10,7 @@ namespace Upsilon.Parser
             Left = left;
             Operator = @operator;
             Right = right;
-            Span = new TextSpan(left.Span.Start, right.Span.End - left.Span.Start);
+            Span = TextSpan.Between(left.Span, right.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.BinaryExpression;

Upsilon/Parser/ExpressionSyntax/FunctionCallExpressionSyntax.cs

@@ -18,7 +18,7 @@ namespace Upsilon.Parser
             OpenParenthesis = openParenthesis;
             Parameters = parameters;
             CloseParenthesis = closeParenthesis;
-            Span = new TextSpan(Identifier.Span.Start, CloseParenthesis.Span.End - Identifier.Span.Start);
+            Span = TextSpan.Between(Identifier.Span, CloseParenthesis.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.FunctionCallExpression;

Upsilon/Parser/ExpressionSyntax/FunctionExpressionSyntax.cs

@@ -23,7 +23,7 @@ namespace Upsilon.Parser
             CloseParenthesis = closeParenthesis;
             Block = block;
             EndToken = endToken;
-            Span = new TextSpan(FunctionToken.Span.Start, EndToken.Span.End - FunctionToken.Span.Start);
+            Span = TextSpan.Between(FunctionToken.Span, endToken.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.FunctionExpression;

Upsilon/Parser/ExpressionSyntax/IndexExpressionSyntax.cs

@@ -17,7 +17,7 @@ namespace Upsilon.Parser
             OpenBracket = openBracket;
             Index = index;
             CloseBracket = closeBracket;
-            Span = new TextSpan(expression.Span.Start, CloseBracket.Span.End - expression.Span.Start);
+            Span = TextSpan.Between(expression.Span, closeBracket.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.IndexExpression;
@@ -41,7 +41,7 @@ namespace Upsilon.Parser
             Expression = expression;
             FullStop = fullStop;
             Index = index;
-            Span = new TextSpan(expression.Span.Start, Index.Span.End - expression.Span.Start);
+            Span = TextSpan.Between(expression.Span, Index.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.FullStopIndexExpression;

Upsilon/Parser/ExpressionSyntax/ParenthesizedExpressionSyntax.cs

@@ -10,7 +10,7 @@ namespace Upsilon.Parser
             OpenParenthesis = openParenthesis;
             Expression = expression;
             CloseParenthesis = closeParenthesis;
-            Span = new TextSpan(OpenParenthesis.Span.Start, CloseParenthesis.Span.End - OpenParenthesis.Span.Start);
+            Span = TextSpan.Between(OpenParenthesis.Span, CloseParenthesis.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.ParenthesizedExpression;

Upsilon/Parser/ExpressionSyntax/TableExpressionSyntax.cs

@@ -11,7 +11,7 @@ namespace Upsilon.Parser
             Expressions = expressions;
             OpenBrace = openBrace;
             CloseBrace = closeBrace;
-            Span = new TextSpan(OpenBrace.Span.Start, CloseBrace.Span.End - OpenBrace.Span.Start);
+            Span = TextSpan.Between(OpenBrace.Span, CloseBrace.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.TableExpression;

Upsilon/Parser/ExpressionSyntax/UnaryExpressionSyntax.cs

@@ -9,7 +9,7 @@ namespace Upsilon.Parser
         {
             Operator = @operator;
             Expression = expression;
-            Span = new TextSpan(Operator.Span.Start, expression.Span.End - Operator.Span.Start);
+            Span = TextSpan.Between(Operator.Span, expression.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.UnaryExpression;

Upsilon/Parser/IdentifierToken.cs

@@ -1,10 +1,11 @@
 using System.Collections.Generic;
+using Upsilon.Text;
 
 namespace Upsilon.Parser
 {
     public class IdentifierToken : SyntaxToken
     {
-        public IdentifierToken(string name, int position)
+        public IdentifierToken(string name, TextSpan position)
             : base(SyntaxKind.Identifier, position, name, null)
         {
             Name = name;

Upsilon/Parser/Lexer.cs

@@ -9,14 +9,15 @@ namespace Upsilon.Parser
     public class Lexer
     {
         private bool SaveComments { get; }
-        private readonly string _text;
+        private readonly string[] _text;
         private readonly Diagnostics _diagnostics;
+        private int _linePosition;
         private int _position;
 
         private Lexer(string text, Diagnostics diagnostics, bool saveComments)
         {
             SaveComments = saveComments;
-            _text = text;
+            _text = text.Split('\n');
             _diagnostics = diagnostics;
         }
 
@@ -26,8 +27,29 @@ namespace Upsilon.Parser
             return lexer.Lex();
         }
 
-        private char Current => _position >= _text.Length ? '\0' : _text[_position];
+        private char Current
-        private char Next => _position + 1 >= _text.Length ? '\0' : _text[_position + 1];
+        {
+            get
+            {
+                var linePos = _linePosition;
+                var pos = _position;
+                if (linePos >= _text.Length) return '\0';
+                if (pos >= _text[linePos].Length) return '\n';
+                return _text[linePos][pos];
+            }
+        }
+
+        private char Next
+        {
+            get
+            {
+                var linePos = _linePosition;
+                var pos     = _position + 1;
+                if (linePos >= _text.Length) return '\0';
+                if (pos >= _text[linePos].Length) return '\n';
+                return _text[linePos][pos];
+            }
+        }
 
         private readonly List<string> _activeComments = new List<string>();
         private ImmutableArray<SyntaxToken> Lex()
@@ -66,46 +88,53 @@ namespace Upsilon.Parser
             switch (Current)
             {
                 case '\0':
-                    return new SyntaxToken(SyntaxKind.EndOfFile, _position, "\0", null);
+                    return new SyntaxToken(SyntaxKind.EndOfFile, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "\0", null);
-                case ' ': case '\t': case '\r': case '\n':
+                case ' ': case '\t': case '\r':
-                    return new SyntaxToken(SyntaxKind.WhiteSpace, _position, Current.ToString(), null);
+                    return new SyntaxToken(SyntaxKind.WhiteSpace, new TextSpan(_linePosition, _position, _linePosition, _position + 1), Current.ToString(), null);
+                case '\n':
+                {
+                    _linePosition++;
+                    var pos = _position;
+                    _position = -1;
+                    return new SyntaxToken(SyntaxKind.WhiteSpace, new TextSpan(_linePosition, pos, _linePosition, pos + 1), "\n", null);
+                }
                 case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
                     return LexNumber();
                 case '+':
-                    return new SyntaxToken(SyntaxKind.Plus, _position, "+", null);
+                    return new SyntaxToken(SyntaxKind.Plus, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "+", null);
                 case '-':
                     if (Next == '-')
                     {
                         _position++;
                         return LexComments();
                     }
-                    return new SyntaxToken(SyntaxKind.Minus, _position, "-", null);
+                    return new SyntaxToken(SyntaxKind.Minus, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "-", null);
                 case '*':
-                    return new SyntaxToken(SyntaxKind.Star, _position, "*", null);
+                    return new SyntaxToken(SyntaxKind.Star, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "*", null);
                 case '/':
-                    return new SyntaxToken(SyntaxKind.Slash, _position, "/", null);
+                    return new SyntaxToken(SyntaxKind.Slash, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "/", null);
                 case '(':
-                    return new SyntaxToken(SyntaxKind.OpenParenthesis, _position, "(", null);
+                    return new SyntaxToken(SyntaxKind.OpenParenthesis, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "(", null);
                 case ')':
-                    return new SyntaxToken(SyntaxKind.CloseParenthesis, _position, ")", null);
+                    return new SyntaxToken(SyntaxKind.CloseParenthesis, new TextSpan(_linePosition, _position, _linePosition, _position + 1), ")", null);
                 case '{':
-                    return new SyntaxToken(SyntaxKind.OpenBrace, _position, "{", null);
+                    return new SyntaxToken(SyntaxKind.OpenBrace, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "{", null);
                 case '}':
-                    return new SyntaxToken(SyntaxKind.CloseBrace, _position, "}", null);
+                    return new SyntaxToken(SyntaxKind.CloseBrace, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "}", null);
                 case '[':
-                    return new SyntaxToken(SyntaxKind.OpenBracket, _position, "[", null);
+                    return new SyntaxToken(SyntaxKind.OpenBracket, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "[", null);
                 case ']':
-                    return new SyntaxToken(SyntaxKind.CloseBracket, _position, "]", null);
+                    return new SyntaxToken(SyntaxKind.CloseBracket, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "]", null);
                 case '.':
-                    return new SyntaxToken(SyntaxKind.FullStop, _position, ".", null);
+                    return new SyntaxToken(SyntaxKind.FullStop, new TextSpan(_linePosition, _position, _linePosition, _position + 1), ".", null);
                 case ',':
-                    return new SyntaxToken(SyntaxKind.Comma, _position, ",", null);
+                    return new SyntaxToken(SyntaxKind.Comma, new TextSpan(_linePosition, _position, _linePosition, _position + 1), ",", null);
                 case '#':
-                    return new SyntaxToken(SyntaxKind.PoundSign, _position, "#", null);
+                    return new SyntaxToken(SyntaxKind.PoundSign, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "#", null);
                 case '%':
-                    return new SyntaxToken(SyntaxKind.PercentSign, _position, "%", null);
+                    return new SyntaxToken(SyntaxKind.PercentSign, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "%", null);
                 case '^':
-                    return new SyntaxToken(SyntaxKind.RoofSign, _position, "^", null);
+                    return new SyntaxToken(SyntaxKind.RoofSign, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "^", null);
                 case '"':
                 case '\'':
                     return LexString(Current);
@@ -113,35 +142,35 @@ namespace Upsilon.Parser
                     if (Next == '=')
                     {
                         _position++;
-                        return new SyntaxToken(SyntaxKind.EqualsEquals, _position - 1, "==", null);
+                        return new SyntaxToken(SyntaxKind.EqualsEquals, new TextSpan(_linePosition, _position - 1, _linePosition, _position + 1), "==", null);
                     }
-                    return new SyntaxToken(SyntaxKind.Equals, _position, "=", null);
+                    return new SyntaxToken(SyntaxKind.Equals, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "=", null);
                 case '~':
                     if (Next == '=')
                     {
                         _position++;
-                        return new SyntaxToken(SyntaxKind.TildeEquals, _position - 1, "~=", null);
+                        return new SyntaxToken(SyntaxKind.TildeEquals, new TextSpan(_linePosition, _position - 1, _linePosition, _position + 1), "~=", null);
                     }
-                    return new SyntaxToken(SyntaxKind.Tilde, _position, "~", null);
+                    return new SyntaxToken(SyntaxKind.Tilde, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "~", null);
                 case '<':
                     if (Next == '=')
                     {
                         _position++;
-                        return new SyntaxToken(SyntaxKind.LessEquals, _position - 1, "<=", null);
+                        return new SyntaxToken(SyntaxKind.LessEquals, new TextSpan(_linePosition, _position - 1, _linePosition, _position + 1), "<=", null);
                     }
-                    return new SyntaxToken(SyntaxKind.Less, _position, "<", null);
+                    return new SyntaxToken(SyntaxKind.Less, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "<", null);
                 case '>':
                     if (Next == '=')
                     {
                         _position++;
-                        return new SyntaxToken(SyntaxKind.GreaterEquals, _position - 1, ">=", null);
+                        return new SyntaxToken(SyntaxKind.GreaterEquals, new TextSpan(_linePosition, _position - 1, _linePosition, _position + 1), ">=", null);
                     }
-                    return new SyntaxToken(SyntaxKind.Greater, _position, ">", null);
+                    return new SyntaxToken(SyntaxKind.Greater, new TextSpan(_linePosition, _position, _linePosition, _position + 1), ">", null);
                 default:
                     if (char.IsLetter(Current) || Current == '_')
                         return LexIdentifierOrKeyword();
-                    _diagnostics.LogBadCharacter(new TextSpan(_position, 1), SyntaxKind.Identifier);
+                    _diagnostics.LogBadCharacter(new TextSpan(_linePosition, _position, _linePosition, _position + 1), SyntaxKind.Identifier);
-                    return new SyntaxToken(SyntaxKind.BadToken, _position, "", null);
+                    return new SyntaxToken(SyntaxKind.BadToken, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "", null);
             }
         }
 
@@ -157,8 +186,8 @@ namespace Upsilon.Parser
                 {
                     if (hasDecimalPoint)
                     {
-                        _diagnostics.LogBadCharacter(new TextSpan(_position, 1), SyntaxKind.Number);
+                        _diagnostics.LogBadCharacter(new TextSpan(_linePosition, _position, _linePosition, _position + 1), SyntaxKind.Number);
-                        return new SyntaxToken(SyntaxKind.BadToken, _position, "", null);
+                        return new SyntaxToken(SyntaxKind.BadToken, new TextSpan(_linePosition, _position, _linePosition, _position + 1), "", null);
                     }
                     hasDecimalPoint = true;
                 }
@@ -172,16 +201,18 @@ namespace Upsilon.Parser
                 o = double.Parse(numStr.ToString());
             else
                 o = long.Parse(numStr.ToString());
-            return new SyntaxToken(SyntaxKind.Number, start, numStr.ToString(), o);
+            return new SyntaxToken(SyntaxKind.Number, new TextSpan(_linePosition, start, _linePosition, _position + 1), numStr.ToString(), o);
         }
 
         private SyntaxToken LexString(char current)
         {
             var start = _position;
             var sb = new StringBuilder();
-            while (_position < _text.Length)
+            while (true)
             {
                 _position++;
+                if (Current == '\0')
+                    break;
                 if (Current == '\\' && Next == current)
                 {
                     sb.Append(current);
@@ -194,15 +225,18 @@ namespace Upsilon.Parser
 
             if (Current != current)
             {
-                _diagnostics.LogBadCharacter(new TextSpan(_position, 1), current, Current);
+                _diagnostics.LogBadCharacter(new TextSpan(_linePosition, _position, _linePosition, _position + 1),
+                    current, Current);
             }
 
             var res = sb.ToString();
-            return new SyntaxToken(SyntaxKind.String, start, $"\"{res}\"", res);
+            return new SyntaxToken(SyntaxKind.String, new TextSpan(_linePosition, start, _linePosition, _position + 1),
+                $"\"{res}\"", res);
         }
 
         private SyntaxToken LexIdentifierOrKeyword()
         {
+            var startLine = _linePosition;
             var start = _position;
             var stringBuilder = new StringBuilder();
             stringBuilder.Append(Current);
@@ -216,19 +250,20 @@ namespace Upsilon.Parser
             var str = stringBuilder.ToString();
             if (kind == SyntaxKind.Identifier)
             {
-                return new IdentifierToken(str, start);
+                return new IdentifierToken(str, new TextSpan(startLine, start, _linePosition, _position));
             }
 
             if (kind == SyntaxKind.ReturnKeyword)
             {
-                return new ReturnSyntaxToken(start, Next == Environment.NewLine[0]);
+                return new ReturnSyntaxToken(new TextSpan(_linePosition, start, _linePosition, _position + 1), Next == Environment.NewLine[0]);
             }
-            return new SyntaxToken(kind, start, str, null);
+            return new SyntaxToken(kind, new TextSpan(_linePosition, start, _linePosition, _position + 1), str, null);
         }
 
         private SyntaxToken LexComments()
         {
             _position++;
+            var startLine = _linePosition;
             var start = _position;
             StringBuilder stringBuilder = null;
             if (SaveComments)
@@ -244,7 +279,7 @@ namespace Upsilon.Parser
             }
             var str = stringBuilder?.ToString();
             _position++;
-            return new SyntaxToken(SyntaxKind.Comment, start,  _position - start, str);
+            return new SyntaxToken(SyntaxKind.Comment, new TextSpan(startLine, start, _linePosition, _position + 1),  _position - start, str);
         }
     }
 }

Upsilon/Parser/ParameterToken.cs

@@ -9,9 +9,9 @@ namespace Upsilon.Parser
         {
             TypeName = typeName;
             IdentifierName = identifierName;
-            var start = identifierName.Span.Start;
+            var start = identifierName.Span;
-            if (typeName != null) start = typeName.Span.Start;
+            if (typeName != null) start = typeName.Span;
-            Span = new TextSpan(start, identifierName.Span.End - start);
+            Span = TextSpan.Between(start, identifierName.Span);
         }
 
         public IdentifierToken TypeName { get; }

Upsilon/Parser/Parser.cs

@@ -29,7 +29,7 @@ namespace Upsilon.Parser
         private SyntaxToken Get(int offset)
         {
             if (_position + offset >= _tokens.Length)
-                return new SyntaxToken(SyntaxKind.EndOfFile, _position + offset, "\0", null);
+                return new SyntaxToken(SyntaxKind.EndOfFile, _tokens.Last().Span, "\0", null);
             else
             {
                 return _tokens[_position + offset];
@@ -49,7 +49,7 @@ namespace Upsilon.Parser
                 return NextToken();
 
             _diagnostics.LogBadCharacter(Current.Span, kind, Current.Kind);
-            return new SyntaxToken(kind, Current.Span.Start, "", null);
+            return new SyntaxToken(kind, Current.Span, "", null);
         }
 
         private StatementSyntax ParseScriptSyntax()
@@ -515,7 +515,7 @@ namespace Upsilon.Parser
             // We'll still want to return a index expression, but we just express that the identifier is empty.
             // This is helpful for tools, etc
             return new FullStopIndexExpressionSyntax(expression, fullStop,
-                new IdentifierToken(string.Empty, fullStop.Span.End));
+                new IdentifierToken(string.Empty, fullStop.Span));
         }
 
         private ExpressionSyntax ParseParenthesizedExpression()

Upsilon/Parser/StatementSyntax/AssignmentStatementSyntax.cs

@@ -12,8 +12,8 @@ namespace Upsilon.Parser
             Identifier  = identifyExpression;
             EqualsToken = equalsToken;
             Expression  = expression;
-            var start = LocalToken?.Span.Start ?? Identifier.Span.Start;
+            var start = LocalToken?.Span ?? Identifier.Span;
-            Span = new TextSpan(start, Expression.Span.End - start);
+            Span = TextSpan.Between(start, expression.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.AssignmentStatement;

Upsilon/Parser/StatementSyntax/BlockStatementSyntax.cs

@@ -13,7 +13,7 @@ namespace Upsilon.Parser
             var first = statements.FirstOrDefault();
             var last = statements.LastOrDefault();
             if (first != null && last != null)
-                Span = new TextSpan(first.Span.Start, last.Span.End - first.Span.Start);
+                Span = TextSpan.Between(first.Span, last.Span);
         }
 
         public ImmutableArray<StatementSyntax> Statements { get; }

Upsilon/Parser/StatementSyntax/FunctionAssignmentStatementSyntax.cs

@@ -10,9 +10,9 @@ namespace Upsilon.Parser
             LocalToken = localToken;
             Identifier = identifier;
             FunctionExpression = functionExpression;
-            var start = Identifier.Span.Start;
+            var start = Identifier.Span;
-            if (localToken != null) start = localToken.Span.Start;
+            if (localToken != null) start = localToken.Span;
-            Span = new TextSpan(start, FunctionExpression.Span.End - start);
+            Span = TextSpan.Between(start, functionExpression.Span);
         }
 
         public SyntaxToken LocalToken    { get; }

Upsilon/Parser/StatementSyntax/GenericForStatementSyntax.cs

@@ -24,7 +24,7 @@ namespace Upsilon.Parser
             DoKeyword = doKeyword;
             Block = block;
             EndKeyword = endKeyword;
-            Span = new TextSpan(forKeyword.Span.Start, endKeyword.Span.End - forKeyword.Span.Start);
+            Span = TextSpan.Between(forKeyword.Span, endKeyword.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.GenericForStatement;

Upsilon/Parser/StatementSyntax/IfStatementSyntax.cs

@@ -16,9 +16,9 @@ namespace Upsilon.Parser
             ThenToken = thenToken;
             Block = block;
             EndToken = endToken;
-            var end = Block.Span.End;
+            var end = Block.Span;
-            if (EndToken != null) end = EndToken.Span.End;
+            if (EndToken != null) end = EndToken.Span;
-            Span = new TextSpan(IfToken.Span.Start, end - IfToken.Span.Start);
+            Span = TextSpan.Between(ifToken.Span, end);
         }
 
         public IfStatementSyntax(SyntaxToken ifToken, ExpressionStatementSyntax condition, SyntaxToken thenToken,
@@ -29,7 +29,7 @@ namespace Upsilon.Parser
             ThenToken     = thenToken;
             Block         = block;
             ElseStatement = elseStatement;
-            Span = new TextSpan(IfToken.Span.Start, ElseStatement.Span.End - IfToken.Span.Start);
+            Span = TextSpan.Between(ifToken.Span, elseStatement.Span);
         }
 
         public IfStatementSyntax(SyntaxToken ifToken, ExpressionStatementSyntax condition, SyntaxToken thenToken,
@@ -40,7 +40,7 @@ namespace Upsilon.Parser
             ThenToken     = thenToken;
             Block         = block;
             NextElseIfStatement = nextElseIfStatement;
-            Span = new TextSpan(IfToken.Span.Start, NextElseIfStatement.Span.End - IfToken.Span.Start);
+            Span = TextSpan.Between(ifToken.Span, nextElseIfStatement.Span);
         }
 
 
@@ -79,7 +79,7 @@ namespace Upsilon.Parser
             yield return Condition;
             yield return ThenToken;
             yield return Block;
-            Span = new TextSpan(ElseIfToken.Span.Start, Block.Span.End - ElseIfToken.Span.Start);
+            Span = TextSpan.Between(ElseIfToken.Span, Block.Span);
         }
 
         public ElseIfStatementSyntax(IfStatementSyntax s)
@@ -119,7 +119,7 @@ namespace Upsilon.Parser
             ElseToken = elseToken;
             Block = block;
             EndToken = endToken;
-            Span = new TextSpan(ElseToken.Span.Start, EndToken.Span.End - ElseToken.Span.Start);
+            Span = TextSpan.Between(elseToken.Span, endToken.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.ElseStatement;

Upsilon/Parser/StatementSyntax/MultiAssignmentStatementSyntax.cs

@@ -19,9 +19,9 @@ namespace Upsilon.Parser
             Identifiers = identifiers.ToImmutableArray();
             AssignmentToken = assignmentToken;
             Expression = expression;
-            var start = Identifiers.First().Span.Start;
+            var start = Identifiers.First().Span;
-            if (localKeyword != null) start = localKeyword.Span.Start;
+            if (localKeyword != null) start = localKeyword.Span;
-            Span = new TextSpan(start, expression.Span.End - start);
+            Span = TextSpan.Between(start, expression.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.MultiAssignmentStatement;

Upsilon/Parser/StatementSyntax/NumericForStatementSyntax.cs

@@ -32,7 +32,7 @@ namespace Upsilon.Parser
             DoToken = doToken;
             Block = block;
             EndToken = endToken;
-            Span = new TextSpan(ForToken.Span.Start, EndToken.Span.End - ForToken.Span.Start);
+            Span = TextSpan.Between(forToken.Span, endToken.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.NumericForStatement;

Upsilon/Parser/StatementSyntax/ReturnStatementSyntax.cs

@@ -9,9 +9,9 @@ namespace Upsilon.Parser
         {
             ReturnToken = returnToken;
             Expression = expression;
-            var end = returnToken.Span.End;
+            var end = returnToken.Span;
-            if (expression != null) end = expression.Span.End;
+            if (expression != null) end = expression.Span;
-            Span = new TextSpan(returnToken.Span.Start, end - returnToken.Span.Start);
+            Span = TextSpan.Between(returnToken.Span, end);
         }
 
         public SyntaxToken ReturnToken { get; }

Upsilon/Parser/StatementSyntax/TableAssigmentStatementSyntax.cs

@@ -15,7 +15,7 @@ namespace Upsilon.Parser
             TableExpression = tableExpression;
             AssignmentToken = assignmentToken;
             Expression      = expression;
-            Span = new TextSpan(tableExpression.Span.Start, expression.Span.End - tableExpression.Span.Start);
+            Span = TextSpan.Between(tableExpression.Span, expression.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.TableAssignmentStatement;

Upsilon/Parser/StatementSyntax/WhileStatementSyntax.cs

@@ -21,7 +21,7 @@ namespace Upsilon.Parser
             Block = block;
             EndKeyword = endKeyword;
 
-            Span = new TextSpan(whileToken.Span.Start, endKeyword.Span.End);
+            Span = TextSpan.Between(whileToken.Span, endKeyword.Span);
         }
 
         public override SyntaxKind Kind => SyntaxKind.WhileStatement;

Upsilon/Parser/SyntaxToken.cs

@@ -5,17 +5,17 @@ namespace Upsilon.Parser
 {
     public class SyntaxToken : SyntaxNode
     {
-        public SyntaxToken(SyntaxKind kind, int position, string text, object value)
+        public SyntaxToken(SyntaxKind kind, TextSpan position, string text, object value)
         {
             Kind  = kind;
-            Span  = new TextSpan(position, text.Length);
+            Span  = position;
             Value = value;
         }
 
-        public SyntaxToken(SyntaxKind kind, int position, int length, object value)
+        public SyntaxToken(SyntaxKind kind, TextSpan position, int length, object value)
         {
             Kind  = kind;
-            Span  = new TextSpan(position, length);
+            Span  = position;
             Value = value;
         }
 
@@ -33,7 +33,7 @@ namespace Upsilon.Parser
     {
         public bool FollowedByLineBreak { get; }
 
-        public ReturnSyntaxToken(int position, bool followedByLineBreak)
+        public ReturnSyntaxToken(TextSpan position, bool followedByLineBreak)
             : base(SyntaxKind.ReturnKeyword, position, "return", null)
         {
             FollowedByLineBreak = followedByLineBreak;

Upsilon/Text/SourceText.cs

@@ -1,109 +1,45 @@
 using System;
+using System.Text;
 
 namespace Upsilon.Text
 {
     public class SourceText
     {
-        private readonly string _text;
+        private readonly string[] _text;
-        private readonly SourceTextLine[] _lines;
 
         public SourceText(string text)
         {
-            _text = text;
+            _text = text.Split('\n');
-            if (string.IsNullOrEmpty(text))
-            {
-                _lines = new SourceTextLine[0];
-                return;
-            }
-            var lines = text.Split(new[] {Environment.NewLine}, StringSplitOptions.None);
-            _lines = new SourceTextLine[lines.Length];
-            var linePos = 0;
-            for (var index = 0; index < lines.Length; index++)
-            {
-                var line = lines[index];
-                _lines[index] = new SourceTextLine(linePos, line.Length + Environment.NewLine.Length);
-                linePos += line.Length + Environment.NewLine.Length;
-            }
         }
 
-        public string GetSpan(int start, int length)
+        public string GetSpan(int startLine, int startPosition, int endLine, int endPosition)
         {
-            if (start < 0)
+            if (startPosition < 0) startPosition = 0;
+            if (startLine == endLine)
             {
-                length += start;
+                return _text[startLine].Substring(startPosition, endPosition - startPosition);
-                start = 0;
+            }
-            };
+            var sb = new StringBuilder();
-            if (start >= _text.Length)
+            sb.Append(_text[startLine].Substring(startPosition));
-                return string.Empty;
+            for (var i = startLine + 1; i < endLine; i++)
-            if (start + length >= _text.Length) length = _text.Length - start;
-            return _text.Substring(start, length);
-        }
-
-        public (int Line, int Pos) GetLinePosition(int spanPos)
-        {
-            var min = 0;
-            var max = _lines.Length - 1;
-            while (min <= max)
             {
-                var mid = (min + max) / 2 ;
+                sb.Append(_text[i]);
-                if (mid >= _lines.Length)
-                {
-                    max = _lines.Length - 1;
-                    continue;
-                }
-                var midLine = _lines[mid];
-                if (midLine.Start <= spanPos && midLine.End > spanPos)
-                {
-                    var pos = spanPos - midLine.Start;
-                    return (mid, pos);
-                }
-                if (spanPos >= midLine.End)
-                {
-                    min = mid + 1;
-                }
-                else if (spanPos < midLine.Start)
-                {
-                    max = mid - 1;
-                }
             }
 
-            if (min >= _lines.Length)
+            if (endPosition > _text[endLine].Length) endPosition = _text[endLine].Length;
-            {
+            sb.Append(_text[endLine].Substring(0, endPosition));
-                min = _lines.Length - 1;
+            return sb.ToString();
-            }
-            var newPos = spanPos - _lines[min].Start;
-            return (min, newPos);
-        }
-
-        public int GetLineStartPos(int lineIndex)
-        {
-            return _lines[lineIndex].Start;
-        }
-
-        public int GetLineCount()
-        {
-            return _lines.Length;
-        }
-
-        public int GetTextLength()
-        {
-            return _text.Length;
         }
 
         public string GetLine(int linePosition)
         {
-            var line = _lines[linePosition];
+            return _text[linePosition];
-            return GetSpan(line.Start, line.LineLength);
-        }
 
-        public SourceTextLine GetLineInfo(int lineIndex)
-        {
-            return _lines[lineIndex];
         }
 
         public string GetSpan(TextSpan span)
         {
-            return GetSpan(span.Start, span.Length);
+            return GetSpan(span.StartLine, span.StartPosition, span.EndLine, span.EndPosition);
         }
     }
 }

Upsilon/Text/TextSpan.cs

@@ -2,19 +2,33 @@ namespace Upsilon.Text
 {
     public struct TextSpan
     {
-        public TextSpan(int start, int length)
+        public int StartLine { get; }
-        {
+        public int StartPosition { get; }
-            Start = start;
+        public int EndLine { get; }
-            Length = length;
+        public int EndPosition { get; }
-        }
 
-        public int Start { get; }
+        public TextSpan(int startLine, int startPosition, int endLine, int endPosition)
-        public int Length { get; }
+        {
-        public int End => Start + Length;
+            StartLine = startLine;
+            StartPosition = startPosition;
+            EndLine = endLine;
+            EndPosition = endPosition;
+        }
 
         public override string ToString()
         {
-            return $"{Start} - {End}";
+            return $"({StartLine}, {StartPosition}) - ({EndLine}, {EndPosition})";
+        }
+
+        public static TextSpan Between(TextSpan start, TextSpan end)
+        {
+            return new TextSpan(start.StartLine, start.StartPosition, end.EndLine, end.EndPosition);
+        }
+
+        public bool Contains(int linePosition, int characterPosition)
+        {
+            return StartLine         >= linePosition && EndLine <= linePosition && characterPosition >= StartPosition &&
+                   characterPosition <= EndPosition;
         }
     }
 }

Upsilon/Utilities/SearchHelper.cs

@@ -7,9 +7,9 @@ namespace Upsilon.Utilities
 {
     public static class SearchHelper
     {
-        public static BoundScope GetScopeAt(this BoundScript script, int characterPosition)
+        public static BoundScope GetScopeAt(this BoundScript script, int linePosition, int characterPosition)
         {
-            foreach (var node in script.GetNodeAtPosition(characterPosition))
+            foreach (var node in script.GetNodeAtPosition(linePosition, characterPosition))
             {
                 if (node is IBoundNodeScopeOwner scopeOwner && scopeOwner.Scope != null)
                 {
@@ -19,14 +19,14 @@ namespace Upsilon.Utilities
             return script.Scope;
         }
 
-        public static BoundNode GetBottomNodeAtPosition(this BoundNode node, int characterPosition)
+        public static BoundNode GetBottomNodeAtPosition(this BoundNode node, int linePosition, int characterPosition)
         {
-            return node.GetNodeAtPosition(characterPosition).First();
+            return node.GetNodeAtPosition(linePosition, characterPosition).First();
         }
-        
+
-        public static BoundStatement GetBottomStatementAtPosition(this BoundNode node, int characterPosition)
+        public static BoundStatement GetBottomStatementAtPosition(this BoundNode node, int linePosition, int characterPosition)
         {
-            return (BoundStatement) node.GetNodeAtPosition(characterPosition).First(x => x is BoundStatement);
+            return (BoundStatement) node.GetNodeAtPosition(linePosition, characterPosition).First(x => x is BoundStatement);
         }
 
         public static Dictionary<string, VariableSymbol> GetBoundScopeVisibleVariables(this BoundScope scope)