using Convention.RScript.Parser;
using System.Collections;
using System.Diagnostics.CodeAnalysis;

namespace Convention.RScript.Runner
{
    public class ExpressionRunner : IRSentenceRunner
    {
        public void Compile(ExpressionParser parser, RScriptSentence sentence, RScriptContext context)
        {
            parser.Compile(sentence.content);
        }

        [return: MaybeNull]
        public object Run(ExpressionParser parser, RScriptSentence sentence, RScriptContext context)
        {
            return parser.Evaluate(sentence.content);
        }

        [return: MaybeNull]
        public IEnumerator RunAsync(ExpressionParser parser, RScriptSentence sentence, RScriptContext context)
        {
            var result = parser.Evaluate(sentence.content);
            if(result is IEnumerator ir)
                yield return ir;
            yield return null;
        }
    }
}