Re: Predicates for all type specifier symbols

[NGALL@G.BBN.COM]

    Date: Fri, 28 Mar 1986  20:16 EST
    From: "Scott E. Fahlman" <Fahlman@C.CS.CMU.EDU>
    To:   common-lisp@SU-AI.ARPA
    Subject: Predicates for all type specifier symbols
    In-Reply-To: Msg of 28 Mar 1986  17:35-EST from Fischer.pa at Xerox.COM
    Message-ID: <FAHLMAN.12194428457.BABYL@C.CS.CMU.EDU>
    
    
    It was proposed long ago that we just flush all the specific type
    specifiers and just go with Typep.  A few pre-existing ones were then
    added back in for compatibility with existing Lisps and existing
    Lispers.  Another ugly compromise, I guess.  A similar situation
    prevails in SETF, where a couple of old favorites were retained, even
    though they are now redundant.
    
    -- Scott
    
	      --------------------

What implementations did commonp pre-exist in :-?  Also, If we want to
steer away from type-specific predicates and towards TYPEP, why does
DEFSTRUCT create a predicate by default?  Also, one disadvantage with
TYPEP is that you have to wrap it up in a lambda-pression in order to
pass it around, i.e., I much prefer #'listp to
#'(lambda (x) (typep x 'list)).

In any case, if we decide to have predicates that always return T and
NIL respectively, (e.g., for KMP condition system proposal) I suggest
that we add the type-specifiers T and NIL to the set of
type-specifiers that have associated predicates, TP and NILP,
repectively.

	-- Nick
P.S. any comments on the desirability of the new type-specifiers that I
proposed?