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: comparison.go
    path of file: ./repos/db/internal/sqlbuilder
    
    the code of the file until where you have to start completion: package sqlbuilder

import (
	"fmt"
	"strings"

	db "github.com/upper/db/v4"
	"github.com/upper/db/v4/internal/adapter"
	"github.com/upper/db/v4/internal/sqladapter/exql"
)

var comparisonOperators = map[adapter.ComparisonOperator]string{
	adapter.ComparisonOperatorEqual:    "=",
	adapter.ComparisonOperatorNotEqual: "!=",

	adapter.ComparisonOperatorLessThan:    "<",
	adapter.ComparisonOperatorGreaterThan: ">",

	adapter.ComparisonOperatorLessThanOrEqualTo:    "<=",
	adapter.ComparisonOperatorGreaterThanOrEqualTo: ">=",

	adapter.ComparisonOperatorBetween:    "BETWEEN",
	adapter.ComparisonOperatorNotBetween: "NOT BETWEEN",

	adapter.ComparisonOperatorIn:    "IN",
	adapter.ComparisonOperatorNotIn: "NOT IN",

	adapter.ComparisonOperatorIs:    "IS",
	adapter.ComparisonOperatorIsNot: "IS NOT",

	adapter.ComparisonOperatorLike:    "LIKE",
	adapter.ComparisonOperatorNotLike: "NOT LIKE",

	adapter.ComparisonOperatorRegExp:    "REGEXP",
	adapter.ComparisonOperatorNotRegExp: "NOT REGEXP",
}

type operatorWrapper struct {
	tu *templateWithUtils
	cv *exql.ColumnValue

	op *adapter.Comparison
	v  interface{}
}

func (ow *operatorWrapper) cmp() *adapter.Comparison {
	if ow.op != nil {
		return ow.op
	}

	if ow.cv.Operator != "" {
		return db.Op(ow.cv.Operator, ow.v).Comparison
	}

	if ow.v == nil {
		return db.Is(nil).Comparison
	}

	args, isSlice := toInterfaceArguments(ow.v)
	if isSli
    
func (ow *operatorWrapper) preprocess() (string, []interface{}) {
	placeholder := "?"

	column, err := ow.cv.Column.Compile(ow.tu.Template)
	if err != nil {
		panic(fmt.Sprintf("could not compile column: %v", err.Error()))
	}

	c := ow.cmp()

	op := ow.tu.comparisonOperatorMapper(c.Operator())

	var args []interface{}

	switch c.Operator() {
	case adapter.ComparisonOperatorNone:
		panic("no operator given")
	case adapter.ComparisonOperatorCustom:
		op = c.CustomOperator()
	case adapter.ComparisonOperatorIn, adapter.ComparisonOperatorNotIn:
		values := c.Value().([]interface{})
		if len(values) < 1 {
			placeholder, args = "(NULL)", []interface{}{}
			break
		}
		placeholder, args = "(?"+strings.Repeat(", ?", len(values)-1)+")", values
	case adapter.ComparisonOperatorIs, adapter.ComparisonOperatorIsNot:
		switch c.Value() {
		case nil:
			placeholder, args = "NULL", []interface{}{}
		case false:
			placeholder, args = "FALSE", []interface{}{}
		case true:
			placeholder, args = "TRUE", []interface{}{}
		}
	case adapter.ComparisonOperatorBetween, adapter.ComparisonOperatorNotBetween:
		values := c.Value().([]interface{})
		placeholder, args = "? AND ?", []interface{}{values[0], values[1]}
	case adapter.ComparisonOperatorEqual:
		v := c.Value()
		if b, ok := v.([]byte); ok {
			v = string(b)
		}
		args = []interface{}{v}
	}

	if args == nil {
		args = []interface{}{c.Value()}
	}

	if strings.Contains(op, ":column") {
		return strings.Replace(op, ":column", column, -1), args
	}

	return column + " " + op + " " + placeholder, args
}