/// <summary>
/// Updates the provided scope with the new variable value.
/// </summary>
/// <param name="scope">The scope object containing variable values and function parameters.</param>
/// <returns>
/// <c>null</c> if successful, or a <see cref="ParseErrorExpression" /> if not.
/// </returns>
public ParseErrorExpression Evaluate(InterpreterScope scope)
{
var assignmentScope = new InterpreterScope(scope)
{
Context = this
};
ExpressionBase result;
var functionDefinition = Value as FunctionDefinitionExpression;
if (functionDefinition != null)
{
scope.AddFunction(functionDefinition);
result = new FunctionReferenceExpression(functionDefinition.Name.Name);
}
else
{
if (!Value.ReplaceVariables(assignmentScope, out result))
{
return((ParseErrorExpression)result);
}
}
return(scope.AssignVariable(Variable, result));
}