do-external-symbols

(do-external-symbols (var [package [result]]) body...)

Evaluates the body once per external (exported) symbol of package -- the current package when omitted -- with var bound to the symbol, then evaluates result with var bound to nil and returns its value (nil when no result form is given). The symbols come in sorted order.

This is an interpreter-only operator: the compiled backends carry no package registry at run time, so a call reaching them is a compile error. Inside a #. read-time form it works everywhere, because the macro-time evaluator resolves it before compilation.