Upsilon/Upsilon/Binder/BoundVariableSymbol.cs

using System.Collections.Generic;
using Upsilon.BaseTypes;
using Upsilon.Binder.VariableSymbols;
using Upsilon.Evaluator;
using Upsilon.Exceptions;
using Upsilon.Text;

namespace Upsilon.Binder
{
    public class BoundVariableSymbol : BoundExpression
    {
        public BoundVariableSymbol(VariableSymbol variableSymbol, bool isCreation, TextSpan span) : base(span)
        {
            VariableSymbol = variableSymbol;
            IsCreation = isCreation;
        }

        public VariableSymbol VariableSymbol { get; }

        public bool IsCreation { get; }
        public override BoundKind Kind => BoundKind.BoundVariableSymbol;
        public override IEnumerable<BoundNode> GetNodeAtPosition(int characterPosition, int i)
        {
            yield return this;
        }

        public override IEnumerable<BoundNode> GetChildren()
        {
            yield break;
        }

        public override TypeContainer ValueType => VariableSymbol.TypeContainer;


        internal override ScriptType Evaluate(EvaluationScope scope, Diagnostics diagnostics, ref EvaluationState state)
        {
            if (scope.TryGet(VariableSymbol, out var val))
            {
                return val;
            }

            throw new EvaluationException(state.Script.FileName, $"Cannot find variable: '{VariableSymbol.Name}'",
                Span);
        }
    }
}