How to replace on match group?

[mdwhatcott]

Consider the following interactions, which I assumed would produce identical output, but which do not:

r1 := regexp.MustCompile("a(sd)f")
m1 := r1.ReplaceAll([]byte("asdf"), []byte(" $1 "))
fmt.Printf("[%s]\n", m1) // this produces the correct output: [ sd ]

r2 := pcre.MustCompile("a(sd)f", 0)
m2 := r2.ReplaceAll([]byte("asdf"), []byte(" $1 "), 0)
fmt.Printf("[%s]\n", m2) // this produces incorrect output: [ $1 ]

The first three lines illustrate the behavior of the standard library. The next three illustrate the behavior of this package.

Is there a way to replace on a match group using this library?

[ye-lin-aung]

I got the same issue.Was it solved ?

[eric-s-raymond]

The PCRE syntax for a backreference is supposed to be \1 rather than $1, but that doesn't work either.

package main

import (
	"fmt"
	pcre "github.com/glenn-brown/golang-pkg-pcre/src/pkg/pcre"
)

func main () {
	from := []byte("aaabbbcccc")
	pattern := "b(.)b"
	re := pcre.MustCompile(pattern, 0)
	result := re.ReplaceAll(from, []byte("ddd\\1"), 0)
	
	fmt.Printf("Result is: %s\n", result)
}