private bool TryValueOrNullDefault(ParserContext context, out IAstNode instr)
{
instr = null;
if (!context.Stream.Consume <IAstNode>(TryValue, context, out var value))
{
return(false);
}
if (!context.Stream.Consume(TokenTypes.DefaultNullValue))
{
return(false);
}
if (!context.Stream.Consume <IAstNode>(TryFactor, context, out var defaultValue))
{
return(false);
}
instr = new ValueWithNullDefaultNode(value, defaultValue);
return(true);
}
/// <summary>
/// Will return the default value if the variable is not defined or its value is null
/// </summary>
/// <param name="node"></param>
/// <returns></returns>
public object Visit(ValueWithNullDefaultNode node)
{
return(node.Value.Accept(this) ?? node.DefaultValue.Accept(this));
}