Some initial work on standard libraries

Upsilon/BaseTypes/LuaFunction.cs

@@ -1,6 +1,7 @@
 using System.Collections.Immutable;
 using System.Linq;
 using System.Reflection;
+using Upsilon.BaseTypes.LuaTypeInterfaces;
 using Upsilon.BaseTypes.UserData;
 using Upsilon.Binder;
 using Upsilon.Evaluator;
@@ -65,7 +66,15 @@ namespace Upsilon.BaseTypes
         {
             var types = variables.Select(x => x.GetCSharpType());
             var method = _method.GetMethod(types.ToArray());
-            var objects = variables.Select(x => x.ToCSharpObject());
+            var objects = variables.Select(x => x.ToCSharpObject()).ToList();
+            var pars = method.GetParameters();
+            if (pars.Length != objects.Count)
+            {
+                for (var i = objects.Count; i < pars.Length; i++)
+                {
+                    objects.Add(null);
+                }
+            }
             return method.Invoke(_object, objects.ToArray()).ToLuaType();
         }
     }

Upsilon/BaseTypes/LuaTable.cs

@@ -1,12 +1,13 @@
 using System.Collections.Generic;
 using System.Linq;
+using Upsilon.BaseTypes.LuaTypeInterfaces;
 using Upsilon.Binder;
 using Upsilon.Evaluator;
 using Upsilon.Text;
 
 namespace Upsilon.BaseTypes
 {
-    internal class LuaTable : LuaType, IIndexable, IScopeOwner
+    internal class LuaTable : LuaType, IIndexable, IScopeOwner, IIterable
     {
         public EvaluationScope EvaluationScope { get; }
 
@@ -15,7 +16,6 @@ namespace Upsilon.BaseTypes
             EvaluationScope = scope;
         }
 
-
         public override Type Type => Type.Table;
         public override object ToCSharpObject()
         {
@@ -43,5 +43,28 @@ namespace Upsilon.BaseTypes
             var s = index.ToString();
             EvaluationScope.Set(new VariableSymbol(s, value.Type, false), value);
         }
+
+
+        private IEnumerator<KeyValuePair<string, LuaType>> _enumerator;
+
+        public bool Next(out LuaType key, out LuaType next)
+        {
+            if (_enumerator == null) _enumerator = EvaluationScope.Variables.GetEnumerator();
+            if (_enumerator.MoveNext())
+            {
+                key = _enumerator.Current.Key.ToLuaType();
+                next = _enumerator.Current.Value;
+                return true;
+            }
+            key = null;
+            next = null;
+            Reset();
+            return false;
+        }
+
+        public void Reset()
+        {
+            _enumerator = null;
+        }
     }
 }

Upsilon/BaseTypes/LuaTypeInterfaces/IITerable.cs

@@ -0,0 +1,8 @@
+namespace Upsilon.BaseTypes.LuaTypeInterfaces
+{
+    public interface IIterable
+    {
+        bool Next(out LuaType key, out LuaType next);
+        void Reset();
+    }
+}

Upsilon/BaseTypes/LuaTypeInterfaces/IIndexable.cs

@@ -8,9 +8,4 @@ namespace Upsilon.BaseTypes
         LuaType Get(Diagnostics diagnostics, TextSpan span, LuaType index, EvaluationScope scope);
         void Set(Diagnostics diagnostics, TextSpan span, LuaType index, LuaType value);
     }
-
-    internal interface IScopeOwner
-    {
-        EvaluationScope EvaluationScope { get; }
-    }
 }

Upsilon/BaseTypes/LuaTypeInterfaces/IScopeOwner.cs

@@ -0,0 +1,9 @@
+using Upsilon.Evaluator;
+
+namespace Upsilon.BaseTypes.LuaTypeInterfaces
+{
+    internal interface IScopeOwner
+    {
+        EvaluationScope EvaluationScope { get; }
+    }
+}

Upsilon/BaseTypes/SimpleLuaTable.cs

@@ -0,0 +1,56 @@
+using System.Collections.Generic;
+using Upsilon.Evaluator;
+using Upsilon.Text;
+
+namespace Upsilon.BaseTypes
+{
+    internal class SimpleLuaTable : LuaType, IIndexable
+    {
+        private readonly IList<LuaType> _objects;
+
+        public SimpleLuaTable(IList<LuaType> objects)
+        {
+            _objects = objects;
+        }
+
+        public LuaType Get(Diagnostics diagnostics, TextSpan span, LuaType index, EvaluationScope scope)
+        {
+            int i;
+            switch (index.Type)
+            {
+                case Type.String:
+                {
+                    var str = (LuaString)index;
+                    i = int.Parse(str.Value) - 1;
+                    break;
+                }
+                case Type.Number:
+                {
+                    var ind = (Number.NumberLong) index;
+                    i = (int) ind.Value - 1;
+                    break;
+                }
+                default:
+                    return null;
+            }
+
+            return _objects[i];
+        }
+
+        public void Set(Diagnostics diagnostics, TextSpan span, LuaType index, LuaType value)
+        {
+            throw new System.NotImplementedException();
+        }
+
+        public override Type Type => Type.Table;
+        public override object ToCSharpObject()
+        {
+            return _objects;
+        }
+
+        public override System.Type GetCSharpType()
+        {
+            return _objects.GetType();
+        }
+    }
+}

Upsilon/Binder/Binder.cs

@@ -258,7 +258,7 @@ namespace Upsilon.Binder
                     }
                     else if (assignment.Type == Type.Unknown && assignment is BoundVariableExpression v)
                     {
-                        v.Variable.Type = variable.Type;
+                        v.Variable.Type = v.Type;
                     }
                     else
                     {

Upsilon/Evaluator/Evaluator.cs

@@ -2,6 +2,7 @@ using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using Upsilon.BaseTypes;
+using Upsilon.BaseTypes.LuaTypeInterfaces;
 using Upsilon.BaseTypes.Number;
 using Upsilon.BaseTypes.UserData;
 using Upsilon.Binder;
@@ -11,10 +12,10 @@ namespace Upsilon.Evaluator
 {
     internal class Evaluator
     {
-        private readonly Diagnostics _diagnostics;
+        private Diagnostics _diagnostics;
         private LuaType _lastValue;
         private LuaType _returnValue;
-        internal EvaluationScope Scope { get; }
+        internal EvaluationScope Scope { get; private set; }
         private bool HasReturned { get; set; }
 
         internal Evaluator(Diagnostics diagnostics, Dictionary<string, LuaType> variables)
@@ -29,6 +30,13 @@ namespace Upsilon.Evaluator
             Scope        = new EvaluationScope(parentScope);
         }
 
+        private Evaluator(){}
+
+        internal static Evaluator CreateWithSetScope(Diagnostics diagnostics, EvaluationScope scope)
+        {
+            return new Evaluator {_diagnostics = diagnostics, Scope = scope};
+        }
+
         public LuaType Evaluate(BoundScript e)
         {
             EvaluateNode(e.Statement);
@@ -282,9 +290,8 @@ namespace Upsilon.Evaluator
         private void EvaluateMultiAssignmentStatement(BoundMultiAssignmentStatement e)
         {
             var val = EvaluateExpression(e.Assignment);
-            if (val.Type == Type.Table)
+            if (val is IIndexable table)
             {
-                var table = (LuaTable) val;
                 for (var i = 0; i < e.Variables.Length; i++)
                 {
                     var variableSymbol = e.Variables[i];

Upsilon/Evaluator/Script.cs

@@ -4,6 +4,7 @@ using System.Collections.Immutable;
 using Upsilon.BaseTypes;
 using Upsilon.Binder;
 using Upsilon.Parser;
+using Upsilon.StandardLibraries;
 using Upsilon.Text;
 using Upsilon.Utilities;
 
@@ -19,13 +20,35 @@ namespace Upsilon.Evaluator
         private Binder.Binder Binder { get; set; }
         private EvaluationScope Scope { get; }
 
+        private static BoundScope _staticBoundScope;
+        private static EvaluationScope _staticScope;
+
+        private static EvaluationScope StaticScope
+        {
+            get
+            {
+                var scope = _staticScope;
+                if (scope != null)
+                {
+                    return scope;
+                }
+
+                var (evaluationScope, boundScope) = StandardLibrary.Create();
+                _staticBoundScope = boundScope;
+                return (_staticScope = evaluationScope);
+            }
+        }
+
         public Script(string scriptString)
         {
             ScriptString = new SourceText(scriptString);
             Diagnostics = new Diagnostics(ScriptString);
             _parsed = Parser.Parser.Parse(scriptString, Diagnostics);
-            Binder = new Binder.Binder(Diagnostics, new Dictionary<string, VariableSymbol>());
-            Evaluator = new Evaluator( Diagnostics, new Dictionary<string, LuaType>());
+
+            Scope = EvaluationScope.CreateWithGetOnlyParent(StaticScope);
+            Binder = new Binder.Binder(Diagnostics, _staticBoundScope.Variables);
+
+            Evaluator = Evaluator.CreateWithSetScope(Diagnostics, Scope);
             Scope = Evaluator.Scope;
         }
 

Upsilon/StandardLibraries/Global.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using Upsilon.BaseTypes;
+using Upsilon.BaseTypes.LuaTypeInterfaces;
+
+// ReSharper disable UnusedMember.Global
+// ReSharper disable MemberCanBePrivate.Global
+
+namespace Upsilon.StandardLibraries
+{
+    internal class BasicFunctions : LuaLibrary
+    {
+        [LuaFunction("assert")]
+        public void Assert(bool boolean, string message = null)
+        {
+            if (!boolean)
+            {
+                Error(message ?? "assertion failed!");
+            }
+        }
+
+        [LuaFunction("error")]
+        public void Error(string message)
+        {
+            throw new Exception(message);
+        }
+
+        [LuaFunction("ipairs")]
+        public LuaType Pairs(IIterable table)
+        {
+            if (!table.Next(out var key, out var next))
+            {
+                return new LuaNull();
+            }
+
+            return new SimpleLuaTable(new List<LuaType>() {key, next});
+        }
+    }
+}

Upsilon/StandardLibraries/LuaFunctionAttribute.cs

@@ -0,0 +1,15 @@
+using System;
+
+namespace Upsilon.StandardLibraries
+{
+    [AttributeUsage(AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
+    public class LuaFunctionAttribute : Attribute
+    {
+        public LuaFunctionAttribute(string name)
+        {
+            Name = name;
+        }
+
+        public string Name { get; }
+    }
+}

Upsilon/StandardLibraries/LuaLibrary.cs

@@ -0,0 +1,27 @@
+using System.Collections.Generic;
+using System.Reflection;
+using Upsilon.BaseTypes;
+using Upsilon.BaseTypes.UserData;
+
+namespace Upsilon.StandardLibraries
+{
+    internal abstract class LuaLibrary
+    {
+        public Dictionary<string, LuaFunction> LoadMethods()
+        {
+            var dictionary = new Dictionary<string, LuaFunction>();
+            var methods = GetType().GetMethods();
+            foreach (var methodInfo in methods)
+            {
+                var attr = methodInfo.GetCustomAttribute<LuaFunctionAttribute>();
+                if (attr != null)
+                {
+                    dictionary.Add(attr.Name, new LuaMethodInfoFunction(new UserDataMethod(methodInfo), this));
+                }
+            }
+
+            return dictionary;
+        }
+
+    }
+}

Upsilon/StandardLibraries/StandardLibrary.cs

@@ -0,0 +1,23 @@
+using System.Collections.Immutable;
+using System.Linq;
+using Upsilon.BaseTypes;
+using Upsilon.Binder;
+using Upsilon.Evaluator;
+
+namespace Upsilon.StandardLibraries
+{
+    internal class StandardLibrary
+    {
+        public static (EvaluationScope, BoundScope) Create()
+        {
+            var basicFunctions = new BasicFunctions().LoadMethods();
+            var scope = new EvaluationScope(basicFunctions.ToDictionary(x => x.Key, x => (LuaType)x.Value));
+            var boundScope =
+                new BoundScope(
+                    scope.Variables.ToDictionary(x => x.Key
+                        , x => (VariableSymbol)new FunctionVariableSymbol(x.Key, x.Value.Type, false, ImmutableArray<VariableSymbol>.Empty){IsBound = true}),
+                    null);
+            return (scope, boundScope);
+        }
+    }
+}

UpsilonTests/StandardLibraryTests/BasicFunctionsTests.cs

@@ -0,0 +1,14 @@
+using Upsilon.Evaluator;
+using Xunit;
+
+namespace UpsilonTests.StandardLibraryTests
+{
+    public class BasicFunctionsTests
+    {
+        [Fact]
+        public void Assert()
+        {
+            new Script("assert(true)").Evaluate();
+        }
+    }
+}