Hi Eric,
my take inline:
On 02/12/2020 17:34, Milles, Eric (TR Technology) wrote:
Traditional "for" (first example) and ARM "try" (last example) support
local variable declarations that are scoped to the statement. In
light of the upcoming "instanceof" enhancement in Java, I was thinking
about possible alternatives for declaring local variables that have
statement scope.
for (int i = ...; ...) {
// i available
}
// i unavailable
Good: Well established & clear syntax
for (x in y index i) { // from Gosu
(http://gosu-lang.github.io/docs.html) -- an alternative to using
eachWithIndex
}
Not fond of: Syntax looks confusing and forced to me, and I see no
advantage over eachWithIndex...
Something along that line could make sense to me, if we loose the
"index" keyword, and allow for multiple iterations in parallel, e.g.:
for(t0 in tables0, t1 in tables1, i2, i3+7, i4+13:2) {
/*
t0, t1, i, and k all advance each for loop step, if we assume i
is a hidden loop variable starting at zero and being incremented by 1
each loop, as follows:
t0 = tables0[i]
t1 = tables1[i]
i2 = i
i3 = i +7
i4 = 2*i + 13
One question would be, if we allow tables0.size() !=
tables1.size() - not sure about that, but it would feel Groovy
compatible to return null if the smaller collection has been exhausted...
*/
}
if (x instanceof T t) { // from Java 14+
}
Good: Might be useful to be able to make the type explicit in some
cases, so yes, also valuable besides being Java compatible.
if (def x = ...) { // tests Groovy truth in this form; may be wrapped
in parens to check something else about "x"
}
try (def ac = ...) {
}
Good: Both useful, and if it works for for, it should work in similar
places.
Cheers,
mg
