Lots of work on rewriting functions to allow more functionality

Upsilon/Binder/Binder.cs

@@ -13,8 +13,8 @@ namespace Upsilon.Binder
         private readonly Diagnostics _diagnostics;
         public BoundScope Scope { get; private set; }
 
-        private Dictionary<FunctionVariableSymbol, UnboundFunctionStatement> _unboundFunctions =
+        private Dictionary<FunctionVariableSymbol, UnboundFunctionExpression> _unboundFunctions =
-            new Dictionary<FunctionVariableSymbol, UnboundFunctionStatement>();
+            new Dictionary<FunctionVariableSymbol, UnboundFunctionExpression>();
 
         public Binder(Diagnostics diagnostics, Dictionary<string, VariableSymbol> variables)
         {
@@ -37,7 +37,7 @@ namespace Upsilon.Binder
                 Scope                                      = Scope.ParentScope;
                 unboundFunctionStatement.Key.IsBound = true;
             }
-            _unboundFunctions = new Dictionary<FunctionVariableSymbol, UnboundFunctionStatement>();
+            _unboundFunctions = new Dictionary<FunctionVariableSymbol, UnboundFunctionExpression>();
             return new BoundScript((BoundBlockStatement) bound);
         }
 
@@ -53,10 +53,10 @@ namespace Upsilon.Binder
                     return BindBlockStatement((BlockStatementSyntax) s);
                 case SyntaxKind.IfStatement:
                     return BindIfStatement((IfStatementSyntax) s);
-                case SyntaxKind.FunctionStatement:
-                    return BindFunctionStatement((FunctionStatementSyntax) s);
                 case SyntaxKind.ReturnStatement:
                     return BindReturnStatement((ReturnStatementSyntax) s);
+                case SyntaxKind.FunctionAssignmentStatement:
+                    return BindFunctionAssignmentStatement((FunctionAssignmentStatementSyntax) s);
             }
 
             throw new NotImplementedException(s.Kind.ToString());
@@ -82,6 +82,8 @@ namespace Upsilon.Binder
                     return BindTableExpression((TableExpressionSyntax) e);
                 case SyntaxKind.IndexExpression:
                     return BindIndexExpression((IndexExpressionSyntax) e);
+                case SyntaxKind.FunctionExpression:
+                    return BindFunctionExpression((FunctionExpressionSyntax) e);
                 case SyntaxKind.BadExpression:
                     break;
                 case SyntaxKind.ScriptUnit:
@@ -305,14 +307,44 @@ namespace Upsilon.Binder
             }
         }
 
-        private BoundStatement BindFunctionStatement(FunctionStatementSyntax e)
+        private BoundExpression BindFunctionExpression(FunctionExpressionSyntax e)
         {
+            var innerScope = new BoundScope(Scope);
+            var parameters = ImmutableArray.CreateBuilder<VariableSymbol>();
+            foreach (var identifierToken in e.Parameters)
+            {
+                var vari = new VariableSymbol(identifierToken.Name, Type.Unknown, true);
+                parameters.Add(vari);
+                innerScope.SetVariable(vari);
+            }
+
+            if (parameters.Count == 0)
+            {
+                Scope = innerScope;
+                var block = BindBlockStatement(e.Block);
+                Scope = Scope.ParentScope;
+                var func = new BoundFunctionExpression(parameters.ToImmutable(), (BoundBlockStatement) block);
+                return func;
+            }
+            else
+            {
+                var unbound = new UnboundFunctionExpression(parameters.ToImmutable(), e.Block);
+                _unboundFunctions.Add(
+                    new FunctionVariableSymbol(Guid.NewGuid().ToString(), Type.Unknown, true, parameters.ToImmutable()),
+                    unbound);
+                return unbound;
+            }
+        }
+
+        private BoundStatement BindFunctionAssignmentStatement(FunctionAssignmentStatementSyntax e)
+        {
+            var func = (BoundFunctionExpression)BindFunctionExpression(e.FunctionExpression);
             var name = e.Identifier.Name;
             var isLocal = e.LocalToken != null;
 
             var innerScope = new BoundScope(Scope);
             var parameters = ImmutableArray.CreateBuilder<VariableSymbol>();
-            foreach (var identifierToken in e.Parameters)
+            foreach (var identifierToken in func.Parameters)
             {
                 var vari = new VariableSymbol(identifierToken.Name, Type.Unknown, true);
                 parameters.Add(vari);
@@ -339,26 +371,14 @@ namespace Upsilon.Binder
                     else
                     {
                         _diagnostics.LogCannotConvert(Type.Function, variable.Type, e.Span);
-                        return new BoundExpressionStatement(null);
+                        return new BoundExpressionStatement(new BoundLiteralExpression(new LuaNull()));
                     }
                 }
             }
 
-            if (parameters.Count == 0)
+            ((FunctionVariableSymbol) variable).IsBound = true;
-            {
+
-                Scope = innerScope;
+            return new BoundFunctionAssignmentStatement(variable, func);
-                var block = BindBlockStatement(e.Block);
-                Scope = Scope.ParentScope;
-                ((FunctionVariableSymbol) variable).IsBound = true;
-                var func = new BoundFunctionStatement(variable, parameters.ToImmutable(), (BoundBlockStatement) block);
-                return func;
-            }
-            else
-            {
-                var unbound = new UnboundFunctionStatement(variable, parameters.ToImmutable(), e.Block);
-                _unboundFunctions.Add((FunctionVariableSymbol) variable, unbound);
-                return unbound;
-            }
         }
 
         private BoundStatement BindReturnStatement(ReturnStatementSyntax e)

Upsilon/Binder/BoundExpressions/BoundFunctionCallExpression.cs

@@ -15,6 +15,6 @@ namespace Upsilon.Binder
         }
 
         public override BoundKind Kind => BoundKind.BoundFunctionCallExpression;
-        public override Type Type => Type.Nil;
+        public override Type Type => Type.Unknown;
     }
 }

Upsilon/Binder/BoundKind.cs

@@ -18,8 +18,9 @@ namespace Upsilon.Binder
         BoundBlockStatement,
         BoundIfStatement,
         BoundElseStatement,
-        BoundFunctionStatement,
+        BoundFunctionExpression,
         BoundPromise,
         BoundReturnStatement,
+        BoundFunctionAssignmentStatement
     }
 }

Upsilon/Binder/BoundStatements/BoundFunctionExpression.cs

@@ -0,0 +1,34 @@
+using System.Collections.Immutable;
+using Upsilon.BaseTypes;
+
+namespace Upsilon.Binder
+{
+    public class BoundFunctionExpression : BoundExpression
+    {
+        public ImmutableArray<VariableSymbol> Parameters { get; }
+        public BoundBlockStatement Block { get; set; }
+
+        public BoundFunctionExpression(ImmutableArray<VariableSymbol> parameters, BoundBlockStatement block)
+        {
+            Parameters = parameters;
+            Block = block;
+        }
+
+        public override BoundKind Kind => BoundKind.BoundFunctionExpression;
+        public override Type Type => Type.Function;
+    }
+
+    public class BoundFunctionAssignmentStatement : BoundStatement
+    {
+        public VariableSymbol Variable { get; }
+        public BoundFunctionExpression Func { get; }
+
+        public BoundFunctionAssignmentStatement(VariableSymbol variable, BoundFunctionExpression func)
+        {
+            Variable = variable;
+            Func = func;
+        }
+
+        public override BoundKind Kind => BoundKind.BoundFunctionAssignmentStatement;
+    }
+}

Upsilon/Binder/BoundStatements/BoundFunctionStatement.cs

@@ -1,21 +0,0 @@
-using System.Collections.Immutable;
-
-namespace Upsilon.Binder
-{
-    public class BoundFunctionStatement : BoundStatement
-    {
-        public VariableSymbol Identifier { get; }
-        public ImmutableArray<VariableSymbol> Parameters { get; }
-        public BoundBlockStatement Block { get; set; }
-
-        public BoundFunctionStatement(VariableSymbol identifier, ImmutableArray<VariableSymbol> parameters,
-            BoundBlockStatement block)
-        {
-            Identifier = identifier;
-            Parameters = parameters;
-            Block = block;
-        }
-
-        public override BoundKind Kind => BoundKind.BoundFunctionStatement;
-    }
-}

Upsilon/Binder/BoundStatements/UnboundFunctionExpression.cs

@@ -3,10 +3,10 @@ using Upsilon.Parser;
 
 namespace Upsilon.Binder
 {
-    public class UnboundFunctionStatement : BoundFunctionStatement
+    public class UnboundFunctionExpression : BoundFunctionExpression
     {
-        public UnboundFunctionStatement(VariableSymbol identifier, ImmutableArray<VariableSymbol> parameters,
+        public UnboundFunctionExpression(ImmutableArray<VariableSymbol> parameters,
-            BlockStatementSyntax unboundBlock) : base(identifier, parameters, null)
+            BlockStatementSyntax unboundBlock) : base(parameters, null)
         {
             UnboundBlock = unboundBlock;
         }

Upsilon/Evaluator/Evaluator.cs

@@ -77,7 +77,9 @@ namespace Upsilon.Evaluator
                 case BoundKind.BoundUnaryExpression:
                 case BoundKind.VariableExpression:
                 case BoundKind.BoundFunctionCallExpression:
+                case BoundKind.BoundFunctionExpression:
                 case BoundKind.BoundTableExpression:
+                case BoundKind.BoundIndexExpression:
                     _lastValue = EvaluateExpression((BoundExpression) b);
                     break;
                 case BoundKind.BoundAssignmentStatement:
@@ -85,8 +87,9 @@ namespace Upsilon.Evaluator
                 case BoundKind.BoundBlockStatement:
                 case BoundKind.BoundIfStatement:
                 case BoundKind.BoundElseStatement:
-                case BoundKind.BoundFunctionStatement:
+                case BoundKind.BoundFunctionAssignmentStatement:
                 case BoundKind.BoundPromise:
+                case BoundKind.BoundReturnStatement:
                     EvaluateStatement((BoundStatement) b);
                     break;
                 default:
@@ -110,15 +113,12 @@ namespace Upsilon.Evaluator
                 case BoundKind.BoundIfStatement:
                     EvaluateBoundIfStatement((BoundIfStatement) e);
                     break;
-                case BoundKind.BoundFunctionStatement:
-                    EvaluateBoundFunctionStatement((BoundFunctionStatement) e);
-                    break;
-                case BoundKind.BoundPromise:
-                    EvaluateUnboundFunctionStatement((UnboundFunctionStatement) e);
-                    break;
                 case BoundKind.BoundReturnStatement:
                     EvaluateReturnStatement((BoundReturnStatement) e);
                     break;
+                case BoundKind.BoundFunctionAssignmentStatement:
+                    EvaluateBoundFunctionAssigmentStatement((BoundFunctionAssignmentStatement) e);
+                    break;
                 default:
                     EvaluateExpressionStatement((BoundExpressionStatement) e);
                     break;
@@ -149,6 +149,11 @@ namespace Upsilon.Evaluator
                     return EvaluateTableExpression((BoundTableExpression) e);
                 case BoundKind.BoundIndexExpression:
                     return EvaluateIndexExpression((BoundIndexExpression) e);
+                case BoundKind.BoundFunctionExpression:
+                    return EvaluateBoundFunctionStatement((BoundFunctionExpression) e);
+                case BoundKind.BoundPromise:
+                    return EvaluateUnboundFunctionStatement((UnboundFunctionExpression) e);
+                    break;
                 default:
                     throw new NotImplementedException();
             }
@@ -254,26 +259,25 @@ namespace Upsilon.Evaluator
             _lastValue = innerEvaluator._lastValue;
         }
 
-        private void EvaluateBoundFunctionStatement(BoundFunctionStatement boundFunctionStatement)
+        private void EvaluateBoundFunctionAssigmentStatement(BoundFunctionAssignmentStatement e)
         {
-            var func = new LuaFunction(boundFunctionStatement.Parameters, boundFunctionStatement.Block);
+            var func = EvaluateBoundFunctionStatement(e.Func);
-            if (boundFunctionStatement.Identifier.Local)
+            if (e.Variable.Local)
-                Scope.Set(boundFunctionStatement.Identifier, func);
+                Scope.Set(e.Variable, func);
             else
-            {
+                Scope.SetGlobal(e.Variable, func);
-                Scope.SetGlobal(boundFunctionStatement.Identifier, func);
-                _lastValue = func;
-            }
         }
 
-        private void EvaluateUnboundFunctionStatement(UnboundFunctionStatement unboundFunctionStatement)
+        private LuaType EvaluateBoundFunctionStatement(BoundFunctionExpression boundFunctionExpression)
         {
-            var func = new LuaFunction(unboundFunctionStatement.Parameters, unboundFunctionStatement.Block);
+            var func = new LuaFunction(boundFunctionExpression.Parameters, boundFunctionExpression.Block);
-            if (unboundFunctionStatement.Identifier.Local)
+            return func;
-                Scope.Set(unboundFunctionStatement.Identifier, func);
+        }
-            else
-                Scope.SetGlobal(unboundFunctionStatement.Identifier, func);
 
+        private LuaType EvaluateUnboundFunctionStatement(UnboundFunctionExpression unboundFunctionExpression)
+        {
+            var func = new LuaFunction(unboundFunctionExpression.Parameters, unboundFunctionExpression.Block);
+            return func;
         }
 
         private LuaType EvaluateBoundFunctionCallExpression(BoundFunctionCallExpression boundFunctionCallExpression)
@@ -281,7 +285,7 @@ namespace Upsilon.Evaluator
             var variable = EvaluateExpression(boundFunctionCallExpression.Identifier);
             if (!(variable is LuaFunction function))
             {
-                throw new Exception("Variable is not a function.");
+                throw new Exception($"Variable is not a function.");
             }
 
             var innerEvaluator = new Evaluator(_diagnostics, Scope);
@@ -316,12 +320,19 @@ namespace Upsilon.Evaluator
                     var value = EvaluateExpression(assignment.BoundExpression);
                     dic.Add(key, value);
                 }
-                else if (boundStatement.Kind == BoundKind.BoundFunctionStatement)
+                else if (boundStatement.Kind == BoundKind.BoundFunctionExpression)
                 {
-                    var function = (BoundFunctionStatement) boundStatement;
+                    var expressionStatement = (BoundExpressionStatement)boundStatement;
-                    var key = function.Identifier;
+                    var function = (BoundFunctionExpression) expressionStatement.Expression;
                     var func = new LuaFunction(function.Parameters, function.Block);
-                    dic.Add(key, func);
+                    dic.Add(new VariableSymbol(currentPos.ToString(), func.Type, false), func);
+                }
+                else if (boundStatement.Kind == BoundKind.BoundFunctionAssignmentStatement)
+                {
+                    var assignment = (BoundFunctionAssignmentStatement)boundStatement;
+                    var key        = assignment.Variable;
+                    var value      = EvaluateExpression(assignment.Func);
+                    dic.Add(key, value);
                 }
                 else
                 {

Upsilon/Parser/ExpressionSyntax/FunctionExpressionSyntax.cs

@@ -3,24 +3,20 @@ using System.Collections.Immutable;
 
 namespace Upsilon.Parser
 {
-    public class FunctionStatementSyntax : StatementSyntax
+    public class FunctionExpressionSyntax : ExpressionSyntax
     {
-        public SyntaxToken LocalToken { get; }
         public SyntaxToken FunctionToken { get; }
-        public IdentifierToken Identifier { get; }
         public SyntaxToken OpenParenthesis { get; }
         public ImmutableArray<IdentifierToken> Parameters { get; }
         public SyntaxToken CloseParenthesis { get; }
         public BlockStatementSyntax Block { get; }
         public SyntaxToken EndToken { get; }
 
-        public FunctionStatementSyntax(SyntaxToken localToken, SyntaxToken functionToken, IdentifierToken identifier,
+        public FunctionExpressionSyntax(SyntaxToken functionToken,
             SyntaxToken openParenthesis, ImmutableArray<IdentifierToken> parameters, SyntaxToken closeParenthesis,
             BlockStatementSyntax block, SyntaxToken endToken)
         {
-            LocalToken = localToken;
             FunctionToken = functionToken;
-            Identifier = identifier;
             OpenParenthesis = openParenthesis;
             Parameters = parameters;
             CloseParenthesis = closeParenthesis;
@@ -28,12 +24,10 @@ namespace Upsilon.Parser
             EndToken = endToken;
         }
 
-        public override SyntaxKind Kind => SyntaxKind.FunctionStatement;
+        public override SyntaxKind Kind => SyntaxKind.FunctionExpression;
         public override IEnumerable<SyntaxNode> ChildNodes()
         {
-            yield return LocalToken;
             yield return FunctionToken;
-            yield return Identifier;
             yield return OpenParenthesis;
             foreach (var identifierToken in Parameters)
             {

Upsilon/Parser/Parser.cs

@@ -70,19 +70,19 @@ namespace Upsilon.Parser
             {
                 return ParseIfStatement(SyntaxKind.IfKeyword);
             }
-
-            if (Current.Kind == SyntaxKind.FunctionKeyword)
-            {
-                return ParseFunctionStatement();
-            }
-            if (Current.Kind == SyntaxKind.LocalKeyword && Next.Kind == SyntaxKind.FunctionKeyword)
-            {
-                return ParseFunctionStatement();
-            }
             if (Current.Kind == SyntaxKind.ReturnKeyword)
             {
                 return ParseReturnStatement();
             }
+            if (Current.Kind == SyntaxKind.FunctionKeyword && Next.Kind != SyntaxKind.OpenParenthesis)
+            {
+                return ParseFunctionAssignmentStatement();
+            }
+            if (Current.Kind == SyntaxKind.LocalKeyword && Next.Kind == SyntaxKind.FunctionKeyword)
+            {
+                return ParseFunctionAssignmentStatement();
+            }
+
 
             return ParseExpressionStatement();
         }
@@ -127,15 +127,9 @@ namespace Upsilon.Parser
             }
         }
 
-        private StatementSyntax ParseFunctionStatement()
+        private ExpressionSyntax ParseFunctionExpression()
         {
-            SyntaxToken localToken = null;
-            if (Current.Kind == SyntaxKind.LocalKeyword)
-            {
-                localToken = NextToken();
-            }
             var functionToken = MatchToken(SyntaxKind.FunctionKeyword);
-            var identifier = (IdentifierToken)MatchToken(SyntaxKind.Identifier);
             var openParenthesis = MatchToken(SyntaxKind.OpenParenthesis);
             var variableBuilder = ImmutableArray.CreateBuilder<IdentifierToken>();
             while (Current.Kind != SyntaxKind.CloseParenthesis)
@@ -146,12 +140,38 @@ namespace Upsilon.Parser
                     NextToken();
             }
             var closeParenthesis = MatchToken(SyntaxKind.CloseParenthesis);
-            var block = ParseBlockStatement(new[] {SyntaxKind.EndKeyword});
+            var block            = ParseBlockStatement(new[] {SyntaxKind.EndKeyword});
-            var endToken = MatchToken(SyntaxKind.EndKeyword);
+            var endToken         = MatchToken(SyntaxKind.EndKeyword);
-            return new FunctionStatementSyntax(localToken, functionToken, identifier, openParenthesis,
+            return new FunctionExpressionSyntax(functionToken, openParenthesis,
                 variableBuilder.ToImmutable(), closeParenthesis, (BlockStatementSyntax) block, endToken);
         }
 
+        private StatementSyntax ParseFunctionAssignmentStatement()
+        {
+            SyntaxToken localToken = null;
+            if (Current.Kind == SyntaxKind.LocalKeyword)
+            {
+                localToken = NextToken();
+            }
+            var functionToken   = MatchToken(SyntaxKind.FunctionKeyword);
+            var identifier      = (IdentifierToken)MatchToken(SyntaxKind.Identifier);
+            var openParenthesis = MatchToken(SyntaxKind.OpenParenthesis);
+            var variableBuilder = ImmutableArray.CreateBuilder<IdentifierToken>();
+            while (Current.Kind != SyntaxKind.CloseParenthesis)
+            {
+                var variableIdentifier = (IdentifierToken)MatchToken(SyntaxKind.Identifier);
+                variableBuilder.Add(variableIdentifier);
+                if (Current.Kind == SyntaxKind.Comma)
+                    NextToken();
+            }
+            var closeParenthesis = MatchToken(SyntaxKind.CloseParenthesis);
+            var block            = ParseBlockStatement(new[] {SyntaxKind.EndKeyword});
+            var endToken         = MatchToken(SyntaxKind.EndKeyword);
+            var functionExpression = new FunctionExpressionSyntax(functionToken, openParenthesis,
+                variableBuilder.ToImmutable(), closeParenthesis, (BlockStatementSyntax) block, endToken);
+            return new FunctionAssignmentStatementSyntax(localToken, identifier, functionExpression);
+        }
+
         private ExpressionStatementSyntax ParseExpressionStatement()
         {
             var expression = ParseExpression();
@@ -167,7 +187,15 @@ namespace Upsilon.Parser
 
         private ExpressionSyntax ParseExpression()
         {
-            var expression = ParseBinaryExpression();
+            ExpressionSyntax expression;
+            if (Current.Kind == SyntaxKind.FunctionKeyword && Next.Kind == SyntaxKind.OpenParenthesis)
+            {
+                expression = ParseFunctionExpression();
+            }
+            else
+            {
+                expression = ParseBinaryExpression();
+            }
             while (Current.Kind == SyntaxKind.OpenBracket || Current.Kind == SyntaxKind.OpenParenthesis)
             {
                 if (Current.Kind == SyntaxKind.OpenBracket)

Upsilon/Parser/StatementSyntax/FunctionAssignmentStatementSyntax.cs

@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+
+namespace Upsilon.Parser
+{
+    public class FunctionAssignmentStatementSyntax : StatementSyntax
+    {
+        public FunctionAssignmentStatementSyntax(SyntaxToken localToken, IdentifierToken identifier, FunctionExpressionSyntax functionExpression)
+        {
+            LocalToken = localToken;
+            Identifier = identifier;
+            FunctionExpression = functionExpression;
+        }
+
+        public SyntaxToken LocalToken    { get; }
+        public IdentifierToken Identifier { get; }
+        public FunctionExpressionSyntax FunctionExpression { get; }
+
+        public override SyntaxKind Kind => SyntaxKind.FunctionAssignmentStatement;
+        public override IEnumerable<SyntaxNode> ChildNodes()
+        {
+            if (LocalToken != null)
+                yield return LocalToken;
+            yield return Identifier;
+            yield return FunctionExpression;
+        }
+    }
+}

Upsilon/Parser/SyntaxKind.cs

@@ -65,7 +65,8 @@ namespace Upsilon.Parser
         IfStatement,
         ElseIfStatement,
         ElseStatement,
-        FunctionStatement,
+        FunctionExpression,
         ReturnStatement,
+        FunctionAssignmentStatement
     }
 }

UpsilonTests/TableTests.cs

@@ -1,3 +1,4 @@
+using System;
 using Upsilon.Evaluator;
 using Xunit;
 
@@ -104,9 +105,9 @@ return table[""test""]()
             const string input = @"
 table = {
     function func()
-        return function func()
+        return function()
             return {
-                function func()
+                function()
                     return 100
                 end
             }