From 7beeb713c9d2fc155876885d0e58928899efbd6a Mon Sep 17 00:00:00 2001
From: Deukhoofd <Deukhoofd@gmail.com>
Date: Sat, 17 Nov 2018 14:49:26 +0100
Subject: [PATCH] Show full lines in error messages in Ycicle

---
 Upsilon/Diagnostics.cs     | 15 +++++++++++++++
 Upsilon/Parser/Parser.cs   |  6 +++---
 Upsilon/Text/SourceText.cs | 10 ++++++++++
 Ycicle/Program.cs          |  4 ++--
 4 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/Upsilon/Diagnostics.cs b/Upsilon/Diagnostics.cs
index 86b785a..12f2cdb 100644
--- a/Upsilon/Diagnostics.cs
+++ b/Upsilon/Diagnostics.cs
@@ -93,6 +93,13 @@ namespace Upsilon
             return $"({linePos.Line},{linePos.Pos})";
         }
 
+        public string LineBeforeError()
+        {
+            var linePos = Diagnostics.ScriptString.GetLinePosition(Span.Start);
+            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);
@@ -103,6 +110,14 @@ namespace Upsilon
             return Diagnostics.ScriptString.GetSpan(Span);
         }
 
+        public string LineAfterError()
+        {
+            var linePos   = Diagnostics.ScriptString.GetLinePosition(Span.Start);
+            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);
diff --git a/Upsilon/Parser/Parser.cs b/Upsilon/Parser/Parser.cs
index 2d34f68..b0fbb70 100644
--- a/Upsilon/Parser/Parser.cs
+++ b/Upsilon/Parser/Parser.cs
@@ -28,9 +28,9 @@ namespace Upsilon.Parser
 
         private SyntaxToken Get(int offset)
         {
-            if (_position + offset >= _tokens.Length)
-                return new SyntaxToken(SyntaxKind.EndOfFile, _position + offset, "\0", null);
-            return _tokens[_position + offset];
+            return _position + offset >= _tokens.Length
+                ? new SyntaxToken(SyntaxKind.EndOfFile, _position + offset, "\0", null)
+                : _tokens[_position                               + offset];
         }
 
         private SyntaxToken NextToken()
diff --git a/Upsilon/Text/SourceText.cs b/Upsilon/Text/SourceText.cs
index 9b15de0..6b5b098 100644
--- a/Upsilon/Text/SourceText.cs
+++ b/Upsilon/Text/SourceText.cs
@@ -60,6 +60,16 @@ namespace Upsilon.Text
             return (min, newPos);
         }
 
+        public int GetLineStartPos(int lineIndex)
+        {
+            return _lines[lineIndex].Start;
+        }
+
+        public SourceTextLine GetLineInfo(int lineIndex)
+        {
+            return _lines[lineIndex];
+        }
+
         public string GetSpan(TextSpan span)
         {
             return GetSpan(span.Start, span.Length);
diff --git a/Ycicle/Program.cs b/Ycicle/Program.cs
index 1c65f66..9fd54a7 100644
--- a/Ycicle/Program.cs
+++ b/Ycicle/Program.cs
@@ -66,13 +66,13 @@ namespace Ycicle
 
             Console.ForegroundColor = ConsoleColor.Gray;
             Console.Write(message.GetDiagnosticPosition() + " ");
-            Console.Write(message.BeforeError());
+            Console.Write(message.LineBeforeError());
 
             Console.ForegroundColor = ConsoleColor.Red;
             Console.Write(message.AtError());
 
             Console.ForegroundColor = ConsoleColor.Gray;
-            Console.Write(message.AfterError());
+            Console.Write(message.LineAfterError());
             Console.WriteLine();
         }
     }