find-symbol

(find-symbol string [package])

Like intern but never creates: returns the symbol when the name is already known to the image, nil otherwise. "Known" means a cl symbol (function, macro, or special form), a keyword, or a user definition. With a package designator the name is looked up in that package instead of the current one; a package that does not exist provides no symbol, so the answer is nil rather than the package-error Common Lisp signals — that keeps probes for optional systems ((find-symbol "TIMESTAMP" :simple-date)) working the same way on every backend.

Deviations from Common Lisp: on the compiled backends (JVM/WASM) only a literal string can answer nil — the check is folded at compile time against the compile-time view (cl symbols plus the program's own defuns), so runtime-defined variables and macros are not visible there (the interpreter checks the live image, including global variables and defmacro macros). A computed name is interned instead, so it always yields a symbol, and its status is read off the spelling that lowering builds (:external for a qualified one, :internal for a bare one) rather than from the image.

A second value reports the ANSI accessibility status of the name in that package — :external, :inherited, :internal, or nil when the package does not provide it, so the two values are nil together: