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Re: Where did <somefunction>p come from?
- To: email@example.com (Tod "Mughi" Casasent), firstname.lastname@example.org
- Subject: Re: Where did <somefunction>p come from?
- From: email@example.com (Steve Strassmann)
- Date: Fri, 27 May 1994 10:38:56 -0700
At 4:19 PM 5/27/94 +0000, Tod "Mughi" Casasent wrote:
>Why does LISP use a "p" at the end of the function? I know that it indicates a
>boolean check, but was questioned on its history. I have to program
>in C++, but still use useful, LISP-like variable and function names, and a
>C++ hack here asked me about it.
It comes from the word "predicate", meaning a boolean check.
Scheme (and Dylan) tend to use '?' in the function name instead of 'p',
but for historical reasons Common Lisp tends to have lots of p's.
If you go read "The Hacker's Dictionary", you can find the anecdote
about the two lisp hackers at the restaurant. One wants to share
a big bowl of soup, and asks the other "split-p soup?"