dnl @ ../doc/m4.texinfo:2845: Origin of test
dnl @ Copyright (C) 2006 Free Software Foundation
dnl @ This file is free software; the Free Software Foundation
dnl @ gives unlimited permission to copy and/or distribute it
dnl @ with or without modifications, as long as this notice
dnl @ is preserved.
define(`f', `ifelse(`$1', `0', `Answer: 0!=1
', eval(`$1>1'), `0', `Answer: $2$1=eval(`$2$1')
', `m4wrap(`f(decr(`$1'), `$2$1*')')')')
dnl @result{}
f(`10')
dnl @result{}
dnl @result{}Answer: 10*9*8*7*6*5*4*3*2*1=3628800