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[ART@THINK-AQUINAS.ARPA: Another reader macro]
Another true-life story from a real User:
Date: Tue, 18 Mar 86 01:19 EST
From: Art Medlar
I've often had a need to comment out a single s-expression
temporarily. Using a semicolon is reasonable only when the
expression is on one line, and it's really annoying when the
line containing the expression has other things that you don't
want to comment out, like closing parentheses of super-expressions.
#-LISPM would probably work, but it's not intended to be used
this way, and it's too long.
So I wrote the #! reader macro. When placed immediately in front
of a list, it causes the reader to completely ignore the list. It's
a lot like #| |# except it operates over a single s-expression and
so needs no termination symbol. It is more useful than (comment ...)
and (ignore ...) since comment returns the symbol COMMENT and ignore
returns NIL. For example, the following form returns T
(and (minusp -1)
(+ 4 3))
To get it, load a:>utility>reader-macros. If it doesn't cause any
problems, I'll add it to the system.