You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: table_operator.rs
    path of file: ./repos/dozer/dozer-sql/src/builder
    
    the code of the file until where you have to start completion: use dozer_core::{
    app::{AppPipeline, PipelineEntryPoint},
    node::ProcessorFactory,
    DEFAULT_PORT_HANDLE,
};
use dozer_sql_expression::sqlparser::ast::{
    Expr, FunctionArg, FunctionArgExpr, ObjectName, TableFactor,
};

use crate::{
    errors::PipelineError,
    table_operator::factory::{get_source_name, TableOperatorProcessorFactory},
    window::factory::WindowProcessorFactory,
};

use super::{
    common::{is_a_pipeline_output, is_an_entry_point, string_from_sql_object_name},
    ConnectionInfo, QueryContext,
};

#[derive(Clone, Debug)]
pub struct TableOperatorDescriptor {
    pub name: String,
    pub args: Vec<TableOperatorAr
    
fn get_table_operator_arg(arg: &FunctionArg) -> Result<TableOperatorArg, PipelineError> {
    match arg {
        FunctionArg::Named { name, arg: _ } => {
            Err(PipelineError::UnsupportedTableOperator(name.to_string()))
        }
        FunctionArg::Unnamed(arg_expr) => match arg_expr {
            FunctionArgExpr::Expr(Expr::Function(function)) => {
                let operator_descriptor =
                    get_table_operator_descriptor(&function.name, Some(&function.args))?;
                if let Some(descriptor) = operator_descriptor {
                    Ok(TableOperatorArg::Descriptor(descriptor))
                } else {
                    Err(PipelineError::UnsupportedTableOperator(
                        string_from_sql_object_name(&function.name),
                    ))
                }
            }
            _ => Ok(TableOperatorArg::Argument(arg.clone())),
        },
    }
}