Lisp Strings

Simple strings¶

#lisp #string

(defparameter msg "Hello, World!")

Strings are always in double quotes. The single quote is for Lisp’s quoting mechanism and cannot be used to create string literals as in some other languages like JavaScript, Python or PHP.

Quotes in strings¶

#string #quote

Escape double quotes that must be part of string (and not delimit the string):

(defparameter sentence "She said, \"Go away!\", and started crying.")

Multi-line strings¶

#multiline #string

Multi-line strings can be created without any special syntax, like in other languages were we are required to escape newlines with a backslash \.

(defparameter usage "Usage: fn [OPTIONS]

  -h              Display this help and exit.
  -H hostname     Hostname to connect.
  -v              Verbose mode.
")

Newlines¶

#lisp #string #newline

Lisp came way before the C and the C-family syntax. This is part of the reason it does not use \n for newlines, but ~%. Example:

(format t "One~%Two~%Three~%")
One
Two
Three

Concatenate strings¶

#lisp #string #concatenate #cat

Use concatenate to combine strings:

(concatenate 'string "May" "the force" "be with" "you")
"Maythe forcebe withyou

Note that it doesn’t add spaces between the concatenated strings. We must take care of the spaces ourselves. For example, here we add a space at the beginning of every next string to be concatenated.

(concatenate 'string "May" " the force" " be with" " you")
"May the force be with you"

• concatenate function in the hyperspec.