On 2016-11-11 19:03, David Walker wrote:
I took a quick stab at implementing, and had something working for
constant expressions, but handling something akin to:
$a = 2;
if (1 < $a++ < 3) {
...
}
Is a bit awkward in our expansions of : if (1 < $a++ && $a++ < 3).
Seems as if when processing the chain here, you'd need to see if the
left node has a child, and somehow ensure you get the evaluated value
somehow, to override the "left" node. So logically expansion of the
above would be if (1 < $a++ && 3 < 3). I think the same would have
too somehow handle (either by syntax error or something) that if a
non-numeric value creeps into a binary-op-compare we error like: if
(1 < (2==3) < 3).
Just some food for thought
--
Dave
I don't see how you would ”logically” get 3 < 3. The very point of
chaining is that each expression is evaluated only once, so the
expression will have the same value in both of the comparisons. So if
the first part is 1<2, then the other must be 2<3 (and not 3<3).
An expression like a < b < c < d can be currently implemented with
temporary variables like this:
a < ($tmp1 = b) && $tmp1 < ($tmp2 = c) && $tmp2 < d
--
Lauri Kenttä
--
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