ExpressionPromoter.Promote Limitations to Detect plausible method matches #389
Description
Hi,
I am highlighting one constraint/issue which is little annoying and could be improved upon.
When I use String.Join method below are the possible overloads which can be called.
+ [0] {System.String Join(System.String, System.String[])}
+ [1] {System.String Join(System.String, System.Object[])}
+ [2] {System.String Join(System.String, System.Collections.Generic.IEnumerable`1[System.String])}
+ [3] {System.String Join(System.String, System.String[], Int32, Int32)}
+ [4] {System.String Join[T](System.String, System.Collections.Generic.IEnumerable`1[T])}
Now in ExpressionPromoter.Promote class of your lib the type match is exact for IEnumerable types.
For example below are the two types, one for string enumerable and another one is int enumerable obj.
{Name = "IEnumerable`1" FullName = "System.Collections.Generic.IEnumerable`1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
{Name = "IEnumerable`1" FullName = "System.Collections.Generic.IEnumerable`1[[System.Int32, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]"}
So ExpressionPromoter.Promote returns the expression for string enumerable but for int enumerable it returns null, due to which we get an error saying no method Join found.
Whereas normally(in c#) when we use int enumerable obj with string.Join it works perfectly, probably because it's matching with the below two types.
+ [1] {System.String Join(System.String, System.Object[])}
+ [4] {System.String Join[T](System.String, System.Collections.Generic.IEnumerable`1[T])}
I would like to know if in your lib can you please make your best method search approach to be more wider which can detect generic methods too? String.Join is just an example, this change can be very useful for many methods.
Code to reproduce the issue:
Works
var strArray = new[] { "1","2","3","4"};
var x = new List<ParameterExpression>();
x.Add(Expression.Parameter(strArray.GetType(), "strArray"));
var config = new ParsingConfig();
string query = "string.Join(\",\" , strArray)";
var e = DynamicExpressionParser.ParseLambda(config, x.ToArray(), null, query);
Delegate del = e.Compile();
var result = del.DynamicInvoke(strArray);
Doesn't Work
var intArray = new[] { 1,2,3,4};
var x = new List<ParameterExpression>();
x.Add(Expression.Parameter(intArray.GetType(), "intArray"));
var config = new ParsingConfig();
string query = "string.Join(\",\" , intArray)";
var e = DynamicExpressionParser.ParseLambda(config, x.ToArray(), null, query);
Delegate del = e.Compile();
var result = del.DynamicInvoke(intArray);
Thanks!