Perl 6 (Raku) takes it a little further with what's known as the Q lang[1]. In their most literal form possible, strings are created by using a Q followed by an

Perl 6 (Raku) takes it a little further with what's known as the Q lang[1]. In their most literal form possible, strings are created by using a Q followed by any pair delimiting surrounding the text. Q[This is a literal string.] #=> This is a literal string. Q!The most literal-est of all.! #=> The most literal-est of all. Q<So I say 'Hello'> #=> So I say 'Hello' From there, adverbs are used to sort of expand a literal string's behavior. For example, `Q:q` (or its more verbose form, `Q:single`) means the string can interpolate \\, \qq[...] and escaping the delimiter with \. Q:q[A simple string] #=> A simple string Q:q{Backslash: \} #=> Backslash: \ Q:q!Backslash: \\! #=> Backslash: \ Q:q{This is a \} so not too early.} #=> This is a } so not too early. In the other hand, `Q:qq` (or `Q:double`) means the string can interpolate scalars (`$`), arrays (`@`), hashes (`%`), function calls (`&`), closure (`{...}`) and backslashes. my $bool = True; my @bools = True, False; my %bools = False => 0, True => 1; Q:qq[Scalar: $bool] #=> «Scalar: True» Q:qq{Array: @bools[]} #=> «Array: True False» Q:qq (Hash: %bools{}) #=> «Hash: False 0␤True 1» Q:qq!Function: %bools.keys.join(' and ')! #=> «Function: False and True» Q:qq<Expression: { 1.0 + 2.0 == 3.0 }> #=> «Expression: True» In order to prevent unwanted interpolation such as in "username@email.xyz" or "https://es.wikipedia.org/wiki/%C3%87" https://es.wikipedia.org/wiki/%C3%87", only scalar variables are interpolated normally. As demonstrated, the array constructor `[]` is used to interpolate a whole array , the hash constructor `{}` for a hash, etc. Since both `Q:q` and `Q:qq` are so common in the language, they have more usual and succinct forms: single quotes (`''`) for `Q:q` and double quotes(`""`) for `Q:qq`. Furthermore the Q can be dropped so `q` or `qq` (followed by a delimiter) can be used as well. From here onwards, a small number of adverbs can be used on the quoting constructs `q` or `qq` to further restrict/expand a string's behavior. For example, for a string that only interpolates scalar ($) and closure ({...}) variables, the adverbs `:s` (or `:scalar`) and `:c` (or `:closure`) can be used. This results in `qq:s:c` (or `qq:sc`, `qq:scalar:closure`). For example: my $var = 25; qq:s:c<$var: { 3**2 + 4**2 }> #=> «25: 25» Another example is the use of `q` with the `:to` (or `:heredoc`) adverb which seems to be the closest construct to Swift 5's custom string delimiters: my $billTheCat = q:to/BILL/; <------- ____ &&& / \ __ _____, `-- | o \' ` &&/ `| | o },-' \____( )__/ ,' \' \ /~~~~~~|. | .}~~~\ ,-----( . | .}--. | . /\___/ `----^,\ \ \_/ BILL [1] https://docs.perl6.org/language/quoting https://docs.perl6.org/language/quoting