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: replacerdata.go
    path of file: ./repos/goby/vendor/github.com/dlclark/regexp2/syntax
    
    the code of the file until where you have to start completion: package syntax

import (
	"bytes"
	"errors"
)

type ReplacerData struct {
	Rep     string
	Strings []string
	Rules   []int
}

const (
	replaceSpecials     = 4
	replaceLeftPortion  = -1
	replaceRightPortion = -2
	replaceLastGroup    = -3
	replaceWholeString  = -4
)

//ErrReplacementError is a general error during parsing the replacement text
var ErrReplacementError = errors.New("Replacement pattern error.")

// NewReplacerData will populate a reusable replacer data struct based on the given replacement string
// and the capture group data from a regexp
func NewReplacerData(rep string, caps map[int]int, cap
    
func NewReplacerData(rep string, caps map[int]int, capsize int, capnames map[string]int, op RegexOptions) (*ReplacerData, error) {
	p := parser{
		options:  op,
		caps:     caps,
		capsize:  capsize,
		capnames: capnames,
	}
	p.setPattern(rep)
	concat, err := p.scanReplacement()
	if err != nil {
		return nil, err
	}

	if concat.t != ntConcatenate {
		panic(ErrReplacementError)
	}

	sb := &bytes.Buffer{}
	var (
		strings []string
		rules   []int
	)

	for _, child := range concat.children {
		switch child.t {
		case ntMulti:
			child.writeStrToBuf(sb)

		case ntOne:
			sb.WriteRune(child.ch)

		case ntRef:
			if sb.Len() > 0 {
				rules = append(rules, len(strings))
				strings = append(strings, sb.String())
				sb.Reset()
			}
			slot := child.m

			if len(caps) > 0 && slot >= 0 {
				slot = caps[slot]
			}

			rules = append(rules, -replaceSpecials-1-slot)

		default:
			panic(ErrReplacementError)
		}
	}

	if sb.Len() > 0 {
		rules = append(rules, len(strings))
		strings = append(strings, sb.String())
	}

	return &ReplacerData{
		Rep:     rep,
		Strings: strings,
		Rules:   rules,
	}, nil
}