alternative to (require ...)

[Sam Halliday]

hi there,

most of the 3rd party packages i have for emacs (such as color-theme, php-mode,
htmlize) are loaded in my ~/.emacs file by statements such as

  (require 'htmlize)

but if this package is not installed on the system, emacs bails on loading the
rest of my ~/.emacs file. this is quite annoying as i like to maintain a single
~/.emacs file and use it wherever i am using emacs.

is there an alternative command i can use, which doesn't result in emacs crying
if it can't find the package? or at least if there is an "if exists" check i
could do and incorporate into a wrapper function, say called (requests ...)

cheers,
Sam
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