From 3d811ff80193950f24928822ee831a7ab0ea2129 Mon Sep 17 00:00:00 2001
From: Deukhoofd <Deukhoofd@gmail.com>
Date: Sun, 11 Nov 2018 21:03:50 +0100
Subject: [PATCH] More work on variables

---
 Upsilon/Binder/BoundScope.cs   |  8 +++++++-
 Upsilon/Evaluator/Evaluator.cs | 22 +++++++++++++---------
 Upsilon/Evaluator/Script.cs    |  6 +++---
 Yc/Program.cs                  |  5 +++--
 4 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/Upsilon/Binder/BoundScope.cs b/Upsilon/Binder/BoundScope.cs
index 348cfbd..c47ce65 100644
--- a/Upsilon/Binder/BoundScope.cs
+++ b/Upsilon/Binder/BoundScope.cs
@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 
 namespace Upsilon.Binder
 {
@@ -10,7 +11,12 @@ namespace Upsilon.Binder
         public BoundScope(BoundScope parentScope)
         {
             _parentScope = parentScope;
-            _variables = new Dictionary<string, VariableSymbol>();
+            _variables   = new Dictionary<string, VariableSymbol>();
+        }
+        public BoundScope(Dictionary<VariableSymbol, object> variables, BoundScope parentScope)
+        {
+            _parentScope = parentScope;
+            _variables = variables.ToDictionary(x => x.Key.Name, x => x.Key);
         }
 
         public void SetVariable(VariableSymbol var)
diff --git a/Upsilon/Evaluator/Evaluator.cs b/Upsilon/Evaluator/Evaluator.cs
index ea9abcb..82063d4 100644
--- a/Upsilon/Evaluator/Evaluator.cs
+++ b/Upsilon/Evaluator/Evaluator.cs
@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using Upsilon.BaseTypes.Number;
 using Upsilon.Binder;
-using Upsilon.Parser;
 
 namespace Upsilon.Evaluator
 {
@@ -10,12 +9,18 @@ namespace Upsilon.Evaluator
     {
         private readonly Diagnostics _diagnostics;
         public Script Script { get; }
-        private Dictionary<string, object> _variables = new Dictionary<string, object>();
+        private readonly Dictionary<VariableSymbol, object> _variables = new Dictionary<VariableSymbol, object>();
 
         public Evaluator(Script script, Diagnostics diagnostics)
         {
             _diagnostics = diagnostics;
-            Script = script;
+            Script       = script;
+        }
+        public Evaluator(Script script, Diagnostics diagnostics, Dictionary<VariableSymbol, object> vars)
+        {
+            _diagnostics = diagnostics;
+            Script       = script;
+            _variables = vars;
         }
 
         public object Evaluate(BoundScript e)
@@ -35,6 +40,8 @@ namespace Upsilon.Evaluator
                     return EvaluateUnaryExpression((BoundUnaryExpression) e);
                 case BoundKind.BoundAssignmentExpression:
                     return EvaluateAssignmentExpression((BoundAssignmenExpression) e);
+                case BoundKind.VariableExpression:
+                    return EvaluateVariableExpression((BoundVariableExpression) e);
                 default:
                     throw new NotImplementedException();
             }
@@ -81,17 +88,14 @@ namespace Upsilon.Evaluator
 
         private object EvaluateAssignmentExpression(BoundAssignmenExpression e)
         {
-            var variableName = e.Variable.Name;
             var val = EvaluateExpression(e.Expression);
-            _variables[variableName] = val;
+            _variables[e.Variable] = val;
             return val;
         }
 
-        private object EvaluateVariableExpression(VariableExpressionSyntax e)
+        private object EvaluateVariableExpression(BoundVariableExpression e)
         {
-            var varName = e.Identifier.Name;
-            _diagnostics.LogUnknownVariable(e.Span, varName);
-            return null;
+            return _variables[e.Variable];
         }
 
     }
diff --git a/Upsilon/Evaluator/Script.cs b/Upsilon/Evaluator/Script.cs
index 08a537e..9b00a95 100644
--- a/Upsilon/Evaluator/Script.cs
+++ b/Upsilon/Evaluator/Script.cs
@@ -13,13 +13,13 @@ namespace Upsilon.Evaluator
         public Diagnostics Diagnostics { get; }
         private Binder.Binder Binder { get; }
 
-        public Script(string scriptString)
+        public Script(string scriptString, Dictionary<VariableSymbol, object> variables = null)
         {
             ScriptString = new SourceText(scriptString);
             Diagnostics = new Diagnostics(ScriptString);
             _parsed = Parser.Parser.Parse(scriptString, Diagnostics);
-            Binder = new Binder.Binder(new BoundScope(null), Diagnostics);
-            Evaluator = new Evaluator(this, Diagnostics);
+            Binder = new Binder.Binder(new BoundScope(variables, null), Diagnostics);
+            Evaluator = new Evaluator(this, Diagnostics, variables);
         }
 
         public object Evaluate()
diff --git a/Yc/Program.cs b/Yc/Program.cs
index 0c0004a..4917efc 100644
--- a/Yc/Program.cs
+++ b/Yc/Program.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using Upsilon;
+using Upsilon.Binder;
 using Upsilon.Evaluator;
 
 namespace Yc
@@ -10,7 +11,7 @@ namespace Yc
         static void Main(string[] args)
         {
             Console.WriteLine("Upsilon REPL");
-            Dictionary<string, object> variables = new Dictionary<string, object>();
+            Dictionary<VariableSymbol, object> variables = new Dictionary<VariableSymbol, object>();
             while (true)
             {
                 Console.Write("» ");
@@ -20,7 +21,7 @@ namespace Yc
                     return;
                 }
 
-                var parsed = new Script(input);
+                var parsed = new Script(input, variables);
                 if (parsed.Diagnostics.Messages.Count > 0)
                 {
                     Console.ForegroundColor = ConsoleColor.Red;