cond

code: eval.c

DEFUN ("cond", Fcond, Scond, 0, UNEVALLED, 0,

doc: /* Try each clause until one succeeds.

Each clause looks like (CONDITION BODY...). CONDITION is evaluated

and, if the value is non-nil, this clause succeeds:

then the expressions in BODY are evaluated and the last one's

value is the value of the cond-form.

If a clause has one element, as in (CONDITION), then the cond-form

returns CONDITION's value, if that is non-nil.

If no clause succeeds, cond returns nil.

usage: (cond CLAUSES...) */)

(Lisp_Object args)

{

Lisp_Object val = args;

while (CONSP (args))

{

Lisp_Object clause = XCAR (args);

val = eval_sub (Fcar (clause));

if (!NILP (val))

{

if (!NILP (XCDR (clause)))

val = Fprogn (XCDR (clause));

break;

}

args = XCDR (args);

}

return val;

}