Re: [Chicken-users] Correct behavior of SRFI-1 any

[Alaric Snell-Pym]

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On 11/29/2011 12:23 PM, Christian Kellermann wrote:

> Actually the result of the else branch of (if (even? x) x) is
> undefined.

Aye. A single-armed "if" is only really useful for conditionalising code
performed for its side effects, as the return value of such an if is
useless.

Because this can be confusing, it's recommended to use "when" for
side-effecting conditionals, which has the added advantage of the body
being arbitrarily long, as there's no need to use position to
distinguish yay and nay branches:

(when (...some test...)
         (...do something...)
         (...do something...)
         (...do something...))

Indeed, a single-armed "if", especially used in a context where the
result is checked (eg, a non-final element of a BEGIN), is potentially
grounds for a compiler warning...

ABS

- --
Alaric Snell-Pym
http://www.snell-pym.org.uk/alaric/
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