I want to ensure variables are interpolated as they are within perl regular expressions. Would rather avoid binding over to other variables in a cascate of "ifs" that would rarely need that variable throughout the code execution. How could I ensure I used the variable?

```
use strict;
use warnings FATAL => "all";

$_="botherther";

my $bo = "bother";
if (/^$bother$/) { # want to consider just $bo here!
  print("Undestood regex as /($bo)ther/.\n");
} else {
  print("Couldnt discern variable.\n");
}

my $bi = { bo => "the" };
if (/^bo$bi->{bo}[r]ther$/) { # now, $bi->{bo} only
  print("Discerned /bo($bi->{bo})[r]/\n");
} else {
  print("Couldnt discern variable.\n");
}

```

I'm not able to find a way to wrap the variables properly within the regex. Of course I could just `my $bi_resolved = $bi->{bo}` or fill the regex with null-thingies (like `[]` or `()`), but this does not feel like a proper separator.

For clarity:

1. I wanted to expand `$bo` into `bother` to get the `/botherther/` string in the first match.
2. I wanted to expand `$bi->{bo}` into `the` to get `<bo><the><[r]ther>`, again `/botherther/` in the second match.
3. Important noting, I don't care for the sake of this context, about the escapes `\Q` and `\E`, *"I am assuming there's never metacharacters within the variables"*.

I have searched thru questions, read documentation, and couldn't find an answer for this. Wrapping in `${}` didn't work for me (that's trying to dereference stuff). So, while searching I feel I am just barking at the wrong tree... It's simply unbelievable nobody ever needed to ask something like that around perlmonks or stackoverflow. I'm probably just looking for the wrong keywords here. :/