[plt-scheme] What are "and" and "or" ?

From: Prabhakar Ragde (plragde at uwaterloo.ca)
Date: Fri Feb 15 14:28:24 EST 2008

Marco Morazan wrote:

> I had students
> complain that they could not pass "and" and "or" around. From a
> padagogical viewpoint it is a little awkward to tell young newcomers
> that "and" and "or" are not primitives.

I tell students while introducing "and" and "or" that they are special 
forms, not functions. Without this, I can't explain the short-cutting 
semantics. They've already seen the special form "cond", so they 
understand. Later on, when we do abstract list functions, I remind them 
again that "and" and "or" are special forms, and tell them about 
"andmap" and "ormap". It hasn't caused any problems for me in the last 
few years. --PR

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