Sadly, most of these fail horribly if you're looking for Common Lisp code.
For example, on Google Code Search, "lang:lisp" turns up Elisp files. "lang:cl" gives Tcl code (!), and "lang:commonlisp" returns nothing. There doesn't seem to be any way to search for Common Lisp code.
github Code Search has a popup menu with the entry "Common Lisp", which looks promising, but it returns a bunch of *.el files (which it labels "(Common Lisp)", strangely).
Other code search sites I've tried are similar. If I want to find Common Lisp code, the best place is still pulling Norvig or Steele or Kiczales off the shelf.
For example, on Google Code Search, "lang:lisp" turns up Elisp files. "lang:cl" gives Tcl code (!), and "lang:commonlisp" returns nothing. There doesn't seem to be any way to search for Common Lisp code.
github Code Search has a popup menu with the entry "Common Lisp", which looks promising, but it returns a bunch of *.el files (which it labels "(Common Lisp)", strangely).
Other code search sites I've tried are similar. If I want to find Common Lisp code, the best place is still pulling Norvig or Steele or Kiczales off the shelf.