LISP I Programmer's Manual - Software Preservation Group

9.1 General FunctionsPredicates:I-atorn[x] : machine languageThe argument of atom is evaluated and the value of atomis true or false depending on whether the argument is or isnot an atomic symbol, In list terminology (see Chapter 6)the argument is an atomic symbol if and only if car[x] = -1.- --null[x] : machine languageThe value of - null is true if its argument is zero, andfalse otherwise.I -and[xl;x2; . . . ;xn] : machine language; special formThe arguments of - and are evaluated in sequence, from leftto right, until one is found that is false, or until the endof the list is reached. The value of - and is false or true respectively .or[xl;x2;*-;x 1 : machine language; special form- nThe arguments of - or are evaluated in sequence, from leftto right, until one is found that is true, or until the end ofthe list is reached. The value of - or is true or false respectively.-not [ x] : machine languageThe value of - not is true if its argument is false, andfalse if its argument is true,