This function has an interesting history.

Someone or something in #guile had clued me there was a magic
string-replace-substring somewhere in guile-user archives. With some luck I
found it, and had bookmarked it, and kept it at the back of my mind for a
good number of months.

Meanwhile I was steadily learning guile, and cleaning up GnuCash. Noting
GnuCash still supports use of guile-2.0, I was finally able to use Mark's
implementation to fix a bad one[1].   After discussing this change with
GnuCash's lead developer, we realised that upgrading the embedded guile in
GnuCash in Windows to 2.2 would solve a whole lot of i18n issues, which it
did.

Hence in a roundabout way, we are thankful for the original post and the
discussion[2] around it.

[1] https://github.com/Gnucash/gnucash/commit/7d15e6e4
[2] https://lists.gnu.org/archive/html/guile-devel/2014-03/msg00058.html

On Sun, 5 Jan 2020 at 12:12, Jan Nieuwenhuizen <janneke@gnu.org> wrote:

> Andy Wingo writes:
>
> > On Fri 20 Dec 2019 18:32, lloda <lloda@sarc.name> writes:
> >
> >> This patch adds string-replace-substring that wingo posted to the
> >> mailing list to (ice-9 strings). This is a commonly used function and a
> >> good implementation isn't trivial, so I think it deserves inclusion.
> >
> > I didn't know that this module existed :)  Sure, why not.  Please fix
> > the commit message when you push.
>
> That's great!  This is one of the things that has always amazed and
> annoyed me to be missing and I have written several half-baken
> implementations of it when I needed something like it.
>
> Would it be too much to ask for some documentation to go with it, so
> that we will be able to find it?
>
> Greetings,
> janneke
>
> --
> Jan Nieuwenhuizen <janneke@gnu.org> | GNU LilyPond http://lilypond.org
> Freelance IT http://JoyofSource.com | Avatar® http://AvatarAcademy.com
>
>