UK TeX FAQ -- question label setURL

### Typesetting URLs

URLs tend to be very long, and contain characters that would naturally prevent them being hyphenated even if they weren’t typically set in `\``ttfamily`, verbatim. Therefore, without special treatment, they often produce wildly overfull `\``hbox`es, and their typeset representation is awful.

There are three packages that help solve this problem:

- The path package, which defines a `\``path` command. The command defines each potential break character as a `\``discretionary`, and offers the user the opportunity of specifying a personal list of potential break characters. Its chief disadvantage is fragility in LaTeX moving arguments. The Eplain macros — define a similar `\``path` command.

  Path, though it works in simple situations, makes no attempt to work with LaTeX (it is irremediably fragile). Despite its long and honourable history, it is no longer recommended for LaTeX use.
- The url package, which defines an `\``url` command (among others, including its own `\``path` command). The command gives each potential break character a maths-mode ‘personality’, and then sets the URL itself (in the user’s choice of font) in maths mode. It can produce (LaTeX-style) ‘robust’ commands (see use of `\``protect`) for use within moving arguments.

  The package ordinarily ignores spaces in the URL, but unfortunately URLs that contain spaces do exist; to typeset them, call the package with the `obeyspaces` option. Two other useful options allow line breaks in the URL in places where they are ordinarily suppressed to avoid confusion: `spaces` to allow breaks at spaces (note, this requires `obeyspaces` as well, and `hyphens` to allow breaks after hyphens. (Note that the package never does “ordinary” hyphenation of names inside an URL.)

  It is possible to use the url package in Plain TeX, with the assistance of the miniltx package (which was originally developed for using the LaTeX graphics package in Plain TeX). A small patch is also necessary: the required sequence is therefore:

  >     \input miniltx
  >     \expandafter\def\expandafter\+\expandafter{\+}
  >     \input url.sty

- The hyperref package, which uses the typesetting code of url, in a context where the typeset text forms the anchor of a link.

The author of this answer prefers the (rather newer) url package (directly or indirectly); both path and url work well with Plain TeX (though of course, the fancy LaTeX facilities of url don’t have much place there). (hyperref isn’t available in a version for use with Plain TeX.)

Note that neither `\``path` (from package path) nor `\``url` (from package url) is robust (in the LaTeX sense). If you need a URL to go in a moving argument, you need the command `\``urldef` from the url package. So one might write:

>     \urldef\faqhome\url{http://www.tex.ac.uk/faq}

after which, `\``faqhome` is robust.

Documentation of both package path and package url is in the package files.

`hyperref.sty`
  macros/latex/contrib/hyperref (or browse the directory); catalogue entry
`miniltx.tex`
  Distributed as part of macros/plain/graphics (or browse the directory); catalogue entry
`path.sty`
  macros/generic/path (or browse the directory); catalogue entry
`url.sty`
  macros/latex/contrib/url (or browse the directory); catalogue entry

This question on the Web: http://www.tex.ac.uk/cgi-bin/texfaq2html?label=setURL