mfgames-nitride-cil/src/Nitride/ExpressionHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;

namespace Nitride
{
    /// <summary>
    /// Helper methods for getting the names of properties.
    /// </summary>
    public static class ExpressionHelper
    {
        public static string GetMemberName<T>(
            Expression<Func<T, object?>> expression)
        {
            return GetMemberName(expression.Body);
        }

        public static IEnumerable<string> GetMemberNames<T>(
            params Expression<Func<T, object?>>[] expressions)
        {
            return expressions
                .Select(x => GetMemberName(x.Body));
        }

        public static IEnumerable<string> GetMemberNames<T>(
            this T instance,
            params Expression<Func<T, object?>>[] expressions)
        {
            return GetMemberNames<T>(expressions);
        }

        private static string GetMemberName(Expression expression)
        {
            if (expression == null)
            {
                throw new ArgumentException(nameof(expression));
            }

            if (expression is MemberExpression memberExpression)
            {
                return memberExpression.Member.Name;
            }

            if (expression is MethodCallExpression methodCallExpression)
            {
                return methodCallExpression.Method.Name;
            }

            if (expression is UnaryExpression unaryExpression)
            {
                return GetMemberName(unaryExpression);
            }

            throw new ArgumentException(nameof(expression));
        }

        private static string GetMemberName(UnaryExpression unaryExpression)
        {
            if (unaryExpression.Operand is MethodCallExpression
                methodCallExpression)
            {
                return methodCallExpression.Method.Name;
            }

            return ((MemberExpression)unaryExpression.Operand).Member.Name;
        }
    }
}