Adds simple string library

Upsilon/StandardLibraries/ScriptFunctionAttribute.cs

@@ -4,6 +4,7 @@ using System.Reflection;
 namespace Upsilon.StandardLibraries
 {
     [AttributeUsage(AttributeTargets.Method, AllowMultiple = true, Inherited = true)]
+    [JetBrains.Annotations.MeansImplicitUse]
     public class ScriptFunctionAttribute : Attribute
     {
         public ScriptFunctionAttribute(string name, string comment = null,

Upsilon/StandardLibraries/StaticScope.cs

@@ -81,6 +81,11 @@ namespace Upsilon.StandardLibraries
             boundFuncs.Add("list",
                 new UserDataVariableSymbol("list", BoundTypeHandler.GetTypeDefinition(typeof(ListLibrary)), true));
 
+            UserDataTypeHandler.LoadType<StringLibrary>();
+            funcs.Add("string", new StringLibrary().ToScriptType());
+            boundFuncs.Add("string",
+                new UserDataVariableSymbol("string", BoundTypeHandler.GetTypeDefinition(typeof(StringLibrary)), true));
+
             var scope = new EvaluationScope(funcs);
             var boundScope = new BoundScope(boundFuncs, null);
             return (scope, boundScope);

Upsilon/StandardLibraries/StringLibrary.cs

@@ -0,0 +1,68 @@
+using System;
+using Upsilon.BaseTypes;
+using Upsilon.BaseTypes.Number;
+
+namespace Upsilon.StandardLibraries
+{
+    internal class StringLibrary
+    {
+        [ScriptFunction("byte", "Get the byte value of the first character of a string", directScriptManipulation: true)]
+        public ScriptNumber Byte(ScriptString str)
+        {
+            return new ScriptNumberLong(str.Value[0]);
+        }
+
+        [ScriptFunction("byte", "Get the byte value of the first character of a string", directScriptManipulation: true)]
+        public ScriptNumber Byte(ScriptString str, ScriptNumberLong index)
+        {
+            if (index < 1 || index > str.Value.Length)
+                return null;
+            var c = str.Value[(int) (index - 1)];
+            return new ScriptNumberLong(c);
+        }
+
+        [ScriptFunction("len", "Return the length of the string passed.", directScriptManipulation: true)]
+        public ScriptNumber Length(ScriptString str)
+        {
+            return str.Length();
+        }
+
+        [ScriptFunction("lower", "Make uppercase characters lower case.", directScriptManipulation: true)]
+        public ScriptString Lower(ScriptString str)
+        {
+            return new ScriptString(str.Value.ToLowerInvariant());
+        }
+
+        [ScriptFunction("reverse", "Reverses a string.", directScriptManipulation: true)]
+        public ScriptString Reverse(ScriptString str)
+        {
+            var cArr = str.Value.ToCharArray();
+            Array.Reverse(cArr);
+            return new ScriptString(new string(cArr));
+        }
+
+        [ScriptFunction("sub", "Make all the lower case characters upper case.", directScriptManipulation: true)]
+        public ScriptString Substring(ScriptString str, ScriptNumberLong startIndex, ScriptNumberLong endIndex = null)
+        {
+            var s = str.Value;
+            var start = startIndex.Value;
+            if (start < 0)
+                start = s.Length + start;
+            if (endIndex == null)
+            {
+                return new ScriptString(str.Value.Substring((int) start));
+            }
+            var end = endIndex.Value;
+            if (end < 0)
+                end = s.Length + end;
+            var length = end - start;
+            return new ScriptString(str.Value.Substring((int) start, (int) length));
+        }
+
+        [ScriptFunction("upper", "Make all the lower case characters upper case.", directScriptManipulation: true)]
+        public ScriptString Upper(ScriptString str)
+        {
+            return new ScriptString(str.Value.ToUpperInvariant());
+        }
+    }
+}

Upsilon/Upsilon.csproj

@@ -14,6 +14,7 @@
     </ItemGroup>
 
     <ItemGroup>
+      <PackageReference Include="JetBrains.Annotations" Version="2018.3.0" />
       <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />
     </ItemGroup>
 

UpsilonTests/StandardLibraryTests/BasicFunctionsTests.cs

@@ -1,6 +1,5 @@
 using System;
 using Upsilon;
-using Upsilon.Evaluator;
 using Xunit;
 
 namespace UpsilonTests.StandardLibraryTests

UpsilonTests/StandardLibraryTests/StringLibraryTests.cs

@@ -0,0 +1,26 @@
+using Upsilon;
+using Xunit;
+
+namespace UpsilonTests.StandardLibraryTests
+{
+    public class StringLibraryTests : TestClass
+    {
+        public StringLibraryTests(StaticScriptFixture fix) : base(fix)
+        {
+        }
+
+        [Fact]
+        public void ByteUse()
+        {
+            var result = Executor.EvaluateScript<long>(@"string.byte(""a"")", Options);
+            Assert.Equal('a', result);
+        }
+
+        [Fact]
+        public void ByteUseIndex()
+        {
+            var result = Executor.EvaluateScript<long>(@"string.byte(""abcd"", 3)", Options);
+            Assert.Equal('c', result);
+        }
+    }
+}