Change some native methods to properties

src/Neo.Compiler.MSIL/MSIL/Conv_Multi.cs

@@ -2,6 +2,7 @@
 using Neo.SmartContract;
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using System.Text.RegularExpressions;
 
@@ -878,8 +879,7 @@ private int ConvertCall(OpCode src, NeoMethod to)
                 Convert1by1(VM.OpCode.PACK, null, to);
 
                 // Push call method name, the first letter should be lowercase.
-                var methodName = defs.Body.Method.Name;
-                ConvertPushString(methodName[..1].ToLowerInvariant() + methodName[1..], src, to);
+                ConvertPushString(GetMethodName(defs.Body.Method), src, to);
 
                 // Push contract hash.
                 ConvertPushDataArray(callhash, src, to);
@@ -923,6 +923,32 @@ private int ConvertCall(OpCode src, NeoMethod to)
             return 0;
         }
 
+        private string GetMethodName(MethodDefinition method)
+        {
+            foreach (var attr in method.CustomAttributes)
+            {
+                if (attr.AttributeType.Name == nameof(DisplayNameAttribute))
+                {
+                    return (string)attr.ConstructorArguments[0].Value;
+                }
+            }
+
+            string methodName = null;
+            if (method.SemanticsAttributes.HasFlag(MethodSemanticsAttributes.Getter))
+            {
+                foreach (PropertyDefinition property in method.DeclaringType.Properties)
+                {
+                    if (property.GetMethod == method)
+                    {
+                        methodName = property.Name;
+                        break;
+                    }
+                }
+            }
+            if (methodName is null) methodName = method.Name;
+            return methodName[..1].ToLowerInvariant() + methodName[1..];
+        }
+
         private List<string> GetAllConstStringAfter(ILMethod method, OpCode src)
         {
             List<string> strlist = new List<string>();

src/Neo.Compiler.MSIL/MSIL/ILModule.cs

@@ -1,6 +1,7 @@
 using Mono.Cecil;
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 
 /// <summary>
 /// This file is responsible for the parsing of the IL DLL. The core parsing is using mono.cecil, which is prearranged to make it easier to use
@@ -121,7 +122,7 @@ public ILField(ILType type, FieldDefinition field)
                     Mono.Collections.Generic.Collection<CustomAttribute> ca = ev.CustomAttributes;
                     foreach (var attr in ca)
                     {
-                        if (attr.AttributeType.Name == "DisplayNameAttribute")
+                        if (attr.AttributeType.Name == nameof(DisplayNameAttribute))
                         {
                             this.displayName = (string)attr.ConstructorArguments[0].Value;
                         }

src/Neo.SmartContract.Framework/Services/Neo/GAS.cs

@@ -7,9 +7,9 @@ namespace Neo.SmartContract.Framework.Services.Neo
     [Contract("0x668e0c1f9d7b70a99dd9e06eadd4c784d641afbc")]
     public class GAS
     {
-        public static extern string Name();
-        public static extern string Symbol();
-        public static extern byte Decimals();
+        public static extern string Name { get; }
+        public static extern string Symbol { get; }
+        public static extern byte Decimals { get; }
         public static extern BigInteger TotalSupply();
         public static extern BigInteger BalanceOf(byte[] account);
     }

src/Neo.SmartContract.Framework/Services/Neo/NEO.cs

@@ -7,9 +7,9 @@ namespace Neo.SmartContract.Framework.Services.Neo
     [Contract("0xde5f57d430d3dece511cf975a8d37848cb9e0525")]
     public class NEO
     {
-        public static extern string Name();
-        public static extern string Symbol();
-        public static extern BigInteger Decimals();
+        public static extern string Name { get; }
+        public static extern string Symbol { get; }
+        public static extern byte Decimals { get; }
         public static extern BigInteger TotalSupply();
         public static extern BigInteger BalanceOf(byte[] account);
 

src/Neo.SmartContract.Framework/Services/Neo/Oracle.cs

@@ -5,7 +5,7 @@ namespace Neo.SmartContract.Framework.Services.Neo
     [Contract("0x3c05b488bf4cf699d0631bf80190896ebbf38c3b")]
     public class Oracle
     {
-        public static extern string Name();
+        public static extern string Name { get; }
         public static extern byte[][] GetOracleNodes();
         public static extern void Request(string url, string filter, string callback, object userData, long gasForResponse);
     }

tests/Neo.Compiler.MSIL.UnitTests/TestClasses/Contract_NativeContracts.cs

@@ -9,17 +9,27 @@ class Contract_NativeContracts : SmartContract.Framework.SmartContract
     {
         public static string NEOName()
         {
-            return Neo.SmartContract.Framework.Services.Neo.NEO.Name();
+            return Neo.SmartContract.Framework.Services.Neo.NEO.Name;
         }
 
         public static string GASName()
         {
-            return Neo.SmartContract.Framework.Services.Neo.GAS.Name();
+            return Neo.SmartContract.Framework.Services.Neo.GAS.Name;
         }
 
         public static string OracleName()
         {
-            return Neo.SmartContract.Framework.Services.Neo.Oracle.Name();
+            return Neo.SmartContract.Framework.Services.Neo.Oracle.Name;
+        }
+
+        public static string NEOSymbol()
+        {
+            return Neo.SmartContract.Framework.Services.Neo.NEO.Symbol;
+        }
+
+        public static string GASSymbol()
+        {
+            return Neo.SmartContract.Framework.Services.Neo.GAS.Symbol;
         }
 
         public static byte[][] getOracleNodes()

tests/Neo.Compiler.MSIL.UnitTests/UnitTest_NativeContracts.cs

@@ -82,6 +82,16 @@ public void Test_NEO()
             var entry = result.Pop();
 
             Assert.AreEqual("NEO", entry.GetString());
+
+            testengine.Reset();
+            result = testengine.ExecuteTestCaseStandard("nEOSymbol");
+
+            Assert.AreEqual(VMState.HALT, testengine.State);
+            Assert.AreEqual(1, result.Count);
+
+            entry = result.Pop();
+
+            Assert.AreEqual("neo", entry.GetString());
         }
 
         [TestMethod]
@@ -98,6 +108,16 @@ public void Test_GAS()
             var entry = result.Pop();
 
             Assert.AreEqual("GAS", entry.GetString());
+
+            testengine.Reset();
+            result = testengine.ExecuteTestCaseStandard("gASSymbol");
+
+            Assert.AreEqual(VMState.HALT, testengine.State);
+            Assert.AreEqual(1, result.Count);
+
+            entry = result.Pop();
+
+            Assert.AreEqual("gas", entry.GetString());
         }
     }
 }

tests/Neo.SmartContract.Framework.UnitTests/TestClasses/Contract_Native.cs

@@ -10,13 +10,13 @@ public class Contract_Native : SmartContract.Framework.SmartContract
         [DisplayName("NEO_Decimals")]
         public static int NEO_Decimals()
         {
-            return (int)NEO.Decimals();
+            return NEO.Decimals;
         }
 
         [DisplayName("NEO_Name")]
         public static string NEO_Name()
         {
-            return NEO.Name();
+            return NEO.Name;
         }
 
         [DisplayName("NEO_BalanceOf")]
@@ -46,13 +46,13 @@ public static (string, BigInteger)[] NEO_GetCandidates()
         [DisplayName("GAS_Decimals")]
         public static int GAS_Decimals()
         {
-            return (int)GAS.Decimals();
+            return GAS.Decimals;
         }
 
         [DisplayName("GAS_Name")]
         public static string GAS_Name()
         {
-            return GAS.Name();
+            return GAS.Name;
         }
 
         public static BigInteger Policy_GetFeePerByte()