The use of here documents is particularly useful ... because it allows you to keep the markup relatively free of escape characters that would otherwise reduce ... readability

(opinionated note on coding style, your preference may vary)

The HERE doc syntax was once a favorite here, but now it has been completely abandoned because:

• 1) There were cases of too many 'escape' chars strewn about, (as mentioned elsewhere in this thread) which motivated a 'zero-tolerance' bias to *absolutely ban all ugly escape sequences*.
• 2) There were cases where *some* of the variables were intended to be interpolated, but not others (e.g., with code-generation scripts) so it was not clear whether to use "EOT" or 'EOT' (as mentioned elsewhere in this thread).
• 3) Indentation hassles (as mentioned elsewhere in this thread).

Because of these issues, we made a stylistic decision not to use HERE doc syntax anymore, and instead use the very flexible quotelike operator with all variables 'concatenated in' instead.

Thus, your example would become:

use strict;
my  $foo = 123.45;
my  $bar = "Martha Stewedprune";

### ---------------------------
print q^
=====
This is an example of
   text taken literally
   except that variables are
   expanded where their
   variable names appear.
   foo: ^.$foo.q^
   bar: ^.$bar.q^

(Our *uninterpolated* variable
   names are "$foo" and "$bar"
   ...
   and we didn't need escape
   chars to tell you that).
^;
### ---------------------------
[download]

All you have to worry about is to make sure your quotelike delim character (caret) is never used in the document. If it is, just change it to something else. Moreover, you can indent this however you want without external module dependencies. Here, we just use comments to make the document visually distinct from the rest of the script.