From 5e9111a08529a5ce71fc62b5c34a721766230df2 Mon Sep 17 00:00:00 2001
From: Alexander Luzgarev <mahalex@gmail.com>
Date: Thu, 16 Jul 2020 11:50:19 +0200
Subject: [PATCH] Fix REPL context handling

---
 Parser/Compilation.cs |  4 ++--
 Parser/Evaluator.cs   | 40 ++++++++++++----------------------------
 Repl/MRepl.cs         |  2 +-
 cmi/Program.cs        |  2 +-
 4 files changed, 16 insertions(+), 32 deletions(-)

diff --git a/Parser/Compilation.cs b/Parser/Compilation.cs
index 8744a58..d566e7e 100644
--- a/Parser/Compilation.cs
+++ b/Parser/Compilation.cs
@@ -21,7 +21,7 @@ namespace Parser
             return Binder.BindProgram(_syntaxTree);
         }
 
-        public EvaluationResult Evaluate(CompilationContext context)
+        public EvaluationResult Evaluate(CompilationContext context, bool inRepl)
         {
             var program = GetBoundProgram();
             if (program.Diagnostics.Length > 0)
@@ -29,7 +29,7 @@ namespace Parser
                 return new EvaluationResult(null, program.Diagnostics);
             }
 
-            var evaluator = new Evaluator(program, context);
+            var evaluator = new Evaluator(program, context, inRepl);
             return evaluator.Evaluate();
         }
     }
diff --git a/Parser/Evaluator.cs b/Parser/Evaluator.cs
index bb06ca0..efa86c8 100644
--- a/Parser/Evaluator.cs
+++ b/Parser/Evaluator.cs
@@ -13,15 +13,16 @@ namespace Parser
         private readonly BoundProgram _program;
         private readonly CompilationContext _context;
         private readonly DiagnosticsBag _diagnostics = new DiagnosticsBag();
-        private bool _insideFunction = false;
+        private bool _inRepl = false;
         private readonly Stack<EvaluationScope> _scopeStack = new Stack<EvaluationScope>();
 
-        public Evaluator(BoundProgram program, CompilationContext context)
+        public Evaluator(BoundProgram program, CompilationContext context, bool inRepl)
         {
             _program = program;
             _context = context;
             var outerScope = new EvaluationScope();
             _scopeStack.Push(outerScope);
+            _inRepl = inRepl;
         }
 
         internal EvaluationResult Evaluate()
@@ -33,7 +34,7 @@ namespace Parser
                     _diagnostics.ReportNotEnoughInputs(
                         new TextSpan(mainFunction.Declaration.Position, mainFunction.Declaration.Position + mainFunction.Declaration.FullWidth),
                         mainFunction.Name);
-                    return new EvaluationResult(null, _diagnostics.ToImmutableArray());
+                return new EvaluationResult(null, _diagnostics.ToImmutableArray());
                 }
                 else
                 {
@@ -458,44 +459,27 @@ namespace Parser
 
         private MObject? GetVariableValue(string name)
         {
-            if (_insideFunction)
+            if (_inRepl)
             {
-                if (_context.Variables.TryGetValue(name, out var globalValue))
-                {
-                    return globalValue;
-                }
-
-                var currentScope = _scopeStack.Peek();
-                return currentScope.Variables.TryGetValue(name, out var localValue) ? globalValue : null;
+                return _context.Variables.TryGetValue(name, out var globalValue) ? globalValue : null;
             }
             else
             {
-                if (_context.Variables.TryGetValue(name, out var globalValue))
-                {
-                    return globalValue;
-                }
-
-                return null;
+                var currentScope = _scopeStack.Peek();
+                return currentScope.Variables.TryGetValue(name, out var localValue) ? localValue : null;
             }
         }
 
         private void SetVariableValue(string name, MObject value)
         {
-            if (_insideFunction)
+            if (_inRepl)
             {
-                if (_context.Variables.ContainsKey(name))
-                {
-                    _context.Variables[name] = value;
-                }
-                else
-                {
-                    var currentScope = _scopeStack.Peek();
-                    currentScope.Variables[name] = value;
-                }
+                _context.Variables[name] = value;
             }
             else
             {
-                _context.Variables[name] = value;
+                var currentScope = _scopeStack.Peek();
+                currentScope.Variables[name] = value;
             }
         }
 
diff --git a/Repl/MRepl.cs b/Repl/MRepl.cs
index ed902d0..c8b1b81 100644
--- a/Repl/MRepl.cs
+++ b/Repl/MRepl.cs
@@ -65,7 +65,7 @@ namespace Repl
 
             TreeRenderer.RenderTree(tree);
             var compilation = Compilation.Create(tree);
-            var evaluationResult = compilation.Evaluate(_context);
+            var evaluationResult = compilation.Evaluate(_context, inRepl: true);
 
             foreach (var diagnostic in evaluationResult.Diagnostics)
             {
diff --git a/cmi/Program.cs b/cmi/Program.cs
index ec5f7fe..f1f0042 100644
--- a/cmi/Program.cs
+++ b/cmi/Program.cs
@@ -36,7 +36,7 @@ namespace cmi
             }
 
             var context = new CompilationContext();
-            var evaluationResult = compilation.Evaluate(context);
+            var evaluationResult = compilation.Evaluate(context, inRepl: false);
 
             foreach (var diagnostic in evaluationResult.Diagnostics)
             {