Ruby: Quote Long String, Heredoc

By Xah Lee. Date: . Last updated: .

Using Different Brackets to Quote String

You can use a bracketing operator to quote a long string.

%q{text}
Literal string. Similar to single quote 'text'.
%Q{text}
Evaluated string. Similar to double quote "text".

Any variable, char escapes, Ruby code, are evaluated inside.

You can use other delimiters for either %q or %Q. For example:

This is useful if your string already contain quote characters. This way, you can change to a different bracket, so you don't need to do escapes in the string.

# quote string that contain quote marks
xx = %q{Alice was beginning to get very tired of sitting by her sister on the bank, and of having nothing to do: once or twice she had peeped into the book her sister was reading, but it had no pictures or conversations in it, «and what is the use of a book,» thought Alice «without pictures or conversation?».}
xx = 4

# quote string and also eval code inside
p %Q{#{xx} and #{1+2} and more} == "4 and 3 and more"

Heredoc

Like Perl, PHP, you have “heredoc” for quoting long string. Start with

<<randomString

where randomString is a contunious random string a to z, capital case or lowercase. End with the same

randomString

on a line by itself. 

aa = 4

bb = <<nHh9t
something something
big string
also code #{aa}
nHh9t

# the #{aa} becomes 4

If you want the text to NOT be interpolated, start your quote string with single quote mark, like this:

yy = 4

xx = <<'cmxBS'
x is #{x}
cmxBS

p xx == "x is \#{x}\n"

If the delimiter string start are double quoted, it's also interpolated.

x = 4

# interpolated
xx3 = <<zYMMy
x is #{x}
zYMMy

p xx3 == "x is 4\n"

Ruby, string