Avoid interpolation in heredoc

Published in

RubyCademy

1 min readMar 8, 2018

Heredoc with interpolation

By default, heredoc accepts interpolation and special characters

For example

venue = "world"str = <<-EOF
I'm the master of the #{venue} !\n
No you're dead bro..
EOF

Output

I'm the master of the world !No you're dead bro..

In order to avoid interpolation you have to surround the heredoc identifier by quotes. Notice the <<-'EOF' in the following example

venue = "world"str = <<-'EOF'
I'm the master of the #{venue} !
No you're dead bro..\n
EOF

Output

I'm the master of the #{venue} !
No you're dead bro..\n

Some text editors understand heredoc and pretty print the string depending on the heredoc flag.

Here is a list of common heredoc flags: <<-SQL, <<-HTML, <<-XML, <<-JSON

<<-SQL
SELECT id
  FROM table
WHERE
  id IS NOT NULL AND id > 200
ORDER BY
  id DESC;
SQL

We’re currently finalizing our first online course: Ruby Mastery.

Join the list for an exclusive release alert! 🔔

Also, you can follow us on x.com as we’re very active on this platform. Indeed, we post elaborate code examples every day.

💚