Determining function argument list in Common Lisp

Question

Is it possible to find out the argument list of a function, given a function object (or a function\'s symbol) in common lisp?

Answer 1

ANSI Common Lisp provides the function FUNCTION-LAMBDA-EXPRESSION, which may return a lambda expression if the implementation supports it and the expression has been recorded. In the lambda expression, the second item is the argument list - as usual.

Otherwise to return an argument list is not defined in the ANSI Common Lisp standard and is part of the specific Lisp implementation. For example in some 'delivered' Lisp applications this information may not be present.

Typically most Common Lisp implementations will have an exported function ARGLIST in some internal package.