# [Scheme-reports] r7rs-draft-6: examples for when and unless

• To: scheme-reports@x
• Subject: [Scheme-reports] r7rs-draft-6: examples for when and unless
• From: Daniel Villeneuve <dvilleneuve@x>
• Date: Wed, 16 May 2012 23:46:33 -0400

The examples of when and unless do not provide the "and prints ..."
block that normally accompanies examples that invoke write/display.
Having two expressions in the scope of when/unless and not showing any
output does not expose the implicit begin that comes with these
"one-sided if" syntaxes.  Also, there is a missing closing bracket after
(display "2") in both current examples.

What about a joined example for both when and unless, such as:

(begin
(when (= 1 1.0)
(display "1 and 1.0 are considered equal")
(newline))
(unless (= 1 1.0)
(display "1 and 1.0 are not considered equal")
(newline)))

prints exactly one of
1 and 1.0 are considered equal \emph{newline}
or
1 and 1.0 are not considered equal\emph{newline}
depending on the details of the implementation.

Of course, that's an artificial example, but it confirms the existence
of the implicit begin to the reader.
--
Daniel Villeneuve