(scheme case-lambda)

(case-lambda <clause1> ...) syntax

Each clause is of the form (<formals> <body>), where <formals> and <body> have the same syntax as in a lambda expression.

A case-lambda expression evaluates to a procedure that accepts a variable number of arguments and is lexically scoped in the same manner as a procedure resulting from a lambda expression. When the procedure is called, the first clause for which the arguments agree with <formals> is selected, where agreement is specified as for the <formals> of a lambda expression. The variables of <formals> are bound to fresh locations, the values of the arguments are stored in those locations, the <body> is evaluated in the extended environment, and the results of <body> are returned as the results of the procedure call.

It is an error for the arguments not to agree with the <formals> of any clause`.


(define add1
    ((a) (add1 a 0))
    ((a b) (+ 1 a b))))

(add1 1) ;; => 2
(add1 1 2) ;; => 4