Re: pattern rules and pattern-specific-variables problem

[Boris Kolpackov]

Greg Chicares <address@hidden> writes:

> In a case like
>
>     fo%bar : FOO = bar
>     foo%ar : BAR = baz
>     fooZbar : @echo ;FOO = $(FOO)  /  BAR = $(BAR)
>
> wouldn't 'determine best match by sorting on length' be indeterminate
> here unless a stable sort algorithm is used?

Well, in this particular case it doesn't matter. In the following example
it does, however

fo%bar : FOO = bar
foo%ar : FOO = baz


> For instance, if qsort() is used, C99 7.20.5.2/4 says
>   If two elements compare as equal, their order in the
>   resulting sorted array is unspecified.
> Would a convention like 'resolve ties in favor of first occurrence'
> or 'sort first by longest matching initial substring' be best here,
> or would it be better to halt with a diagnostic message saying that
> two rules are equally applicable?

I think in case of a tie we should use the old rule, i.e., the
definition order.

-boris