Transform.cs

using System.IO;
using System.Threading.Tasks;
using System.Xml;
using System.Xml.Xsl;
using Waher.Script;
using Waher.Script.Abstraction.Elements;
using Waher.Script.Exceptions;
using Waher.Script.Model;
using Waher.Script.Objects;
 
namespace Waher.Content.Xsl.Functions
{
    public class Transform : FunctionTwoScalarVariables
    {
        public Transform(ScriptNode Xml, ScriptNode Xslt, int Start, int Length, Expression Expression)
            : base(Xml, Xslt, Start, Length, Expression)
        {
        }
 
        public override string FunctionName => nameof(Transform);
 
        public override bool UpgradeScalarsToSameSet => false;
 
        public override IElement EvaluateScalar(IElement Argument1, IElement Argument2, Variables Variables)
        {
            if (!(Argument1.AssociatedObjectValue is string s))
            {
                if (Argument1.AssociatedObjectValue is XmlDocument Xml)
                    s = Xml.OuterXml;
                else
                    s = Expression.ToExpressionString(Argument1.AssociatedObjectValue);
            }
 
            if (!(Argument2.AssociatedObjectValue is XslCompiledTransform Xslt))
                throw new ScriptRuntimeException("Second parameter must be an XSL Transform (XSLT) object.", this);
 
            return this.DoTransform(s, Xslt);
        }
 
        public override Task<IElement> EvaluateScalarAsync(IElement Argument1, IElement Argument2, Variables Variables)
        {
            return Task.FromResult<IElement>(this.EvaluateScalar(Argument1, Argument2, Variables));
        }
 
        private IElement DoTransform(string Xml, XslCompiledTransform Xslt)
        {
            return new StringValue(XSL.Transform(Xml, Xslt));
        }
 
        public override IElement EvaluateScalar(string Argument1, string Argument2, Variables Variables)
        {
            using (StringReader s = new StringReader(Argument2))
            {
                using (XmlReader r = XmlReader.Create(s))
                {
                    XslCompiledTransform Xslt = new XslCompiledTransform();
                    Xslt.Load(r);
 
                    return this.DoTransform(Argument1, Xslt);
                }
            }
        }
 
    }
}