Bobbin's API only has a single function:

(bobbin:wrap string-or-strings width)

The simplest way to use Bobbin is to pass it a string:

(bobbin:wrap "hello, world!" 10)

Every line in the string returned by wrap will contain at most width characters (not including the newline itself).


Bobbin will try to break lines at whitespace. It will only break a word in the middle if there's no other choice. It does not try to hyphenate, or parse hyphenation:

(bobbin:wrap "This is a test of Bobbin's line-breaking." 10)
"This is a
test of

Initial whitespace (e.g. indentation) will be preserved, unless even the first word cannot be fit if it were included. Bobbin does not try to indent any broken lines, but this may be added in the future:

(bobbin:wrap "    foo bar baz" 10)
"    foo
bar baz"

(bobbin:wrap "    thisisjusttoolong" 10)

Whitespace between words will be preserved, unless a line is broken at that point. This does the right thing for those of us who put two spaces after a period, as God intended:

(bobbin:wrap "there  are  two  spaces  between  these  words" 12)
"there  are
two  spaces
these  words"

Existing line breaks in the text are preserved. Bobbin will only ever add line breaks, never remove them:

(bobbin:wrap (format nil "foo~%bar baz frob") 7)
bar baz


For convenience, you can also pass wrap a list of strings. Each string is treated as a separate line and wrapped as described above. The results are returned as a (flat) list of lines, each of which will be no more than width characters long:

(bobbin:wrap (list "here is a line."
                   "and here is another line")
("here is"
 "a line."
 "and here"

The strings in the list may contain newlines themselves — they will be split and the result will still be one flat list of lines. You can use this to trick Bobbin into returning a list even when you're just passing it one string, by wrapping the input in a list:

(defparameter *foo* (format nil "foo and bar~%cat and mouse"))

(bobbin:wrap *foo* 8)
"foo and
cat and

(bobbin:wrap (list *foo*) 8)
("foo and"
 "cat and"

Possible Future Features

Bobbin aims to be simple, but may grow a bit more functionality in the future (PRs welcome):