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From: jeff@aiai.ed.ac.uk (Jeff Dalton)
Newsgroups: comp.lang.lisp
Subject: hard to write (was Re: STRUCTUREP)
Message-ID: <3534@skye.ed.ac.uk>
Date: 12 Oct 90 14:21:15 GMT
References: <1990Oct10.130925.18317@hellgate.utah.edu> <756@forsight.Jpl.Nasa.Gov>
Reply-To: jeff@aiai.UUCP (Jeff Dalton)
Organization: AIAI, University of Edinburgh, Scotland
Lines: 38

In article <756@forsight.Jpl.Nasa.Gov> gat@robotics.Jpl.Nasa.Gov (Erann Gat) writes:
>> The "hard-to-write" argument is the one I hear most frequently,

>I think that the people who buy Common Lisp implementations and have to pay
>for thousands of obscure features that they never use might care about it as
>well.

Hundreds would be more accurate.  And I suppose these same people
would also complain about having to buy the whole C library.  (Vendors
may like this attitude, because it lets them justify unbundling,
something that is usually not, I suspect, revenue-neutral.)

>> I don't think Common Lisp function names are cryptic. There are a few
>> macros whose syntax is unfortunate, mostly for hysterical raisons. 
>> 
>> I keep a copy of CLTL around when I write code, mostly to check that
>> what I'm about to write isn't already part of the language. It's easy
>> to write obscure code in any Lisp.
>
>How can you be sure that what you are writing isn't already part of the
>language, but that it has an obscure name and is tucked away in a remote
>corner of Steele's tome? 

 (1) It often, perhaps even usually, doesn't hurt to implement
     something yourself.  Indeed, it may be more efficient than
     the built-in version, it you leave out some of the features.

 (2) It's a good idea to look through the book in order to get a feel
     for what it contains and where things are, rather than just look
     things up when you suspect there might be something you want.

>                          (and pity the poor programmer who spends hours
>searching through the book saying to himself, "There's just got to be a
>way to test for structures, there's just got to be! :->)

And the people who assume EQUAL must descend structures, notice
that it works in one CL, and then discover that it's not portable.
There are a number of little traps in CL, I agree.