Configurable default numeric type

README.md

@@ -1,4 +1,4 @@
-# Dynamic Expresso
+# Dynamic Expresso
 
 [![NuGet version](https://badge.fury.io/nu/DynamicExpresso.Core.svg)](http://badge.fury.io/nu/DynamicExpresso.Core)
 [![Build Status](https://public-davideicardi.visualstudio.com/dynamic-expresso/_apis/build/status/dynamic-expresso-CI?branchName=master)](https://public-davideicardi.visualstudio.com/dynamic-expresso/_build?definitionId=4
@@ -360,6 +360,22 @@ CollectionAssert.AreEqual(new[] { "x", "y" },
 			  detectedIdentifiers.UnknownIdentifiers.ToArray());
 ```
 
+## Default number type
+In C #, numbers are usually interpreted as integers or doubles if they have decimal places.
+
+In some cases it may be useful to be able to configure the default type of numbers if no particular suffix is ​​specified: for example in financial calculations, where usually numbers are interpreted as decimal type.
+
+In these cases you can set the default number type using `Interpreter.SetDefaultNumberType`  method.
+
+```csharp
+var target = new Interpreter();
+
+target.SetDefaultNumberType(DefaultNumberType.Decimal);
+
+Assert.IsInstanceOf(typeof(System.Decimal), target.Eval("45"));
+Assert.AreEqual(10M/3M, target.Eval("10/3")); // 3.33333333333 instead of 3
+```
+
 ## Limitations
 Not every C# syntaxes are supported. Here some examples of NOT supported features:
 

src/DynamicExpresso.Core/DefaultNumberType.cs

@@ -0,0 +1,19 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace DynamicExpresso
+{
+    /// <summary>
+    /// Setting the default number types when no suffix is specified
+    /// </summary>
+    public enum DefaultNumberType
+    {
+        Default = 0, //(Int by default or Double if real number)
+        Int = 1,
+        Long = 2,
+        Single = 3,
+        Double = 4,
+        Decimal = 5
+    }
+}

src/DynamicExpresso.Core/Interpreter.cs

@@ -1,4 +1,4 @@
-using DynamicExpresso.Parsing;
+using DynamicExpresso.Parsing;
 using DynamicExpresso.Reflection;
 using DynamicExpresso.Visitors;
 using System;
@@ -102,6 +102,18 @@ public AssignmentOperators AssignmentOperators
 		#endregion
 
 		#region Options
+
+		/// <summary>
+		/// Allow to set de default numeric type when no suffix is specified (Int by default, Double if real number)
+		/// </summary>
+		/// <param name="defaultNumberType"></param>
+		/// <returns></returns>
+		public Interpreter SetDefaultNumberType(DefaultNumberType defaultNumberType)
+		{
+			_settings.DefaultNumberType = defaultNumberType;
+			return this;
+		}
+
 		/// <summary>
 		/// Allows to enable/disable assignment operators. 
 		/// For security when expression are generated by the users is more safe to disable assignment operators.

src/DynamicExpresso.Core/Parsing/Parser.cs

@@ -44,13 +44,17 @@ public static Expression Parse(ParserArguments arguments)
 		private readonly BindingFlags _bindingCase;
 		private readonly MemberFilter _memberFilterCase;
 
+		private readonly DefaultNumberType _defaultNumberType;
+
 		private Parser(ParserArguments arguments)
 		{
 			_arguments = arguments;
 
 			_bindingCase = arguments.Settings.CaseInsensitive ? BindingFlags.IgnoreCase : BindingFlags.Default;
 			_memberFilterCase = arguments.Settings.CaseInsensitive ? Type.FilterNameIgnoreCase : Type.FilterName;
 
+			_defaultNumberType = arguments.Settings.DefaultNumberType;
+
 			_expressionText = arguments.ExpressionText ?? string.Empty;
 			_expressionTextLength = _expressionText.Length;
 			SetTextPos(0);
@@ -656,6 +660,9 @@ private Expression ParseIntegerLiteral()
 
 			text = text.Substring(0, numberEnd + 1);
 
+			// No suffix find, verify if DefaultNumberType.Long is specified
+			if (_defaultNumberType == DefaultNumberType.Long) isLong = true;
+
 			if (text[0] != '-')
 			{
 				if (!ulong.TryParse(text, ParseLiteralUnsignedNumberStyle, ParseCulture, out ulong value))
@@ -703,14 +710,30 @@ private Expression ParseRealLiteral()
 				if (decimal.TryParse(text.Substring(0, text.Length - 1), ParseLiteralDecimalNumberStyle, ParseCulture, out decimal dc))
 					value = dc;
 			}
-			else
+			else if (last == 'D' || last == 'd')
 			{
-				if (last == 'D' || last == 'd')
-					text = text.Substring(0, text.Length - 1);
-
-				if (double.TryParse(text, ParseLiteralDoubleNumberStyle, ParseCulture, out double d))
+				if (double.TryParse(text.Substring(0, text.Length - 1), ParseLiteralDoubleNumberStyle, ParseCulture, out double d))
 					value = d;
 			}
+			else
+			{
+				// No suffix find, use DefaultNumberType settigns if specified (Double default)
+				if (_defaultNumberType == DefaultNumberType.Decimal)
+				{
+					if (decimal.TryParse(text, ParseLiteralDecimalNumberStyle, ParseCulture, out decimal dc))
+						value = dc;
+				}
+				else if (_defaultNumberType == DefaultNumberType.Single)
+				{
+					if (float.TryParse(text, ParseLiteralDecimalNumberStyle, ParseCulture, out float f))
+						value = f;
+				}
+				else
+				{
+					if (double.TryParse(text, ParseLiteralDoubleNumberStyle, ParseCulture, out double d))
+						value = d;
+				}
+			}
 
 			if (value == null)
 				throw CreateParseException(_token.pos, ErrorMessages.InvalidRealLiteral, text);
@@ -2348,7 +2371,17 @@ private void NextToken()
 
 					if (char.IsDigit(_parseChar))
 					{
-						t = TokenId.IntegerLiteral;
+						//RealLiteral if DefaultNumberType settings is set to real type
+						if (_defaultNumberType == DefaultNumberType.Single || _defaultNumberType == DefaultNumberType.Double || _defaultNumberType == DefaultNumberType.Decimal)
+						{
+							t = TokenId.RealLiteral;
+						}
+						else
+						{
+							//IntegerLiteral by default
+							t = TokenId.IntegerLiteral;
+						}
+
 						do
 						{
 							NextChar();

src/DynamicExpresso.Core/Parsing/ParserSettings.cs

@@ -9,7 +9,7 @@ internal class ParserSettings
 		private readonly Dictionary<string, Identifier> _identifiers;
 		private readonly Dictionary<string, ReferenceType> _knownTypes;
 		private readonly HashSet<MethodInfo> _extensionMethods;
-
+		
 		public ParserSettings(bool caseInsensitive)
 		{
 			CaseInsensitive = caseInsensitive;
@@ -25,6 +25,8 @@ public ParserSettings(bool caseInsensitive)
 			_extensionMethods = new HashSet<MethodInfo>();
 
 			AssignmentOperators = AssignmentOperators.All;
+
+			DefaultNumberType = DefaultNumberType.Default;
 		}
 
 		public IDictionary<string, ReferenceType> KnownTypes
@@ -48,6 +50,12 @@ public bool CaseInsensitive
 			private set;
 		}
 
+		public DefaultNumberType DefaultNumberType
+		{
+			get;
+			set;
+		}
+
 		public StringComparison KeyComparison
 		{
 			get;