On Mon, 19 Mar 2012 17:43:45 -0400, Gord Tomlin wrote:
>IMHO using '*' to represent null violates the Principle of Least
>Astonishment. '*' is often used in masking to represent "anything",
>which is a long way from null.
>
>How about using NULL to represent null, e.g.,
>
>thing3(option1,NULL) /* This would define another thing and say "even
>if you have a default, global value for option2, pretend you don't" */
>
I am very accustomed to, and comfortable with the convention
common to Rexx and POSIX shell script, both of which distinguish
between undefined and any defined value: empty string, "NULL",
or whatever. So, I'd add the rule:
thing3(option1,NULL) /* Means option2 is unset. */
thing3(option1,'NULL') /* means option2 is the 4-character string, "NULL".)
... (reserved words are never quoted; values are quoted to avoid conflict
with reserved words or when lexically required, to avoid any encroachment
on the potential value space.)
-- gil
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