Hi OC,
I think that generally speaking, hiding/masking an outer variable like
that is a quite undesireable coding style, so I like the current Groovy
behavior (even if it deviates from C, evidently - I never used code like
that in C, so I did not even know it was valid ;-) ).
What specific use case did you have in mind, where just renaming the
inner variable to i0, j, k, ... or the outer to index, idx, ... would
not be the better solution ?
(I use an informal coding style where I use variable names with a number
at the end for short term / loop / etc variables, and for parameters and
variables who live throughout a method or larger block I use no number
postfix or longer names; the short name / long name meta at least is
quite common, I think)
Cheers,
mg
On 02/12/2020 18:13, OCsite wrote:
Hello there,
when touching this stuff, it would be extremely desirable primarily to
fix the scoping/obscuring of same-named variables, which Groovy at the
moment does wrong, same as the demented Java thing:
===
89 ocs*/tmp>* <q.groovy
def i=0 // outer
println "i=$i (outer)"
for (int i=1 /* inner */;i<2;i++) println "i=$i (inner)"
println "i=$i (outer again)"
89 ocs*/tmp>* /usr/local/groovy-4.0.0-alpha-1/bin/groovy q
org.codehaus.groovy.control.MultipleCompilationErrorsException:
startup failed:
/private/tmp/q.groovy: 3: The current scope already contains a
variable of the name i
@ line 3, column 10.
for (int i=1 /* inner */;i<2;i++) println "i=$i (inner)"
^
1 error
90 ocs*/tmp>*
===
This is how it *should* work:
===
90 ocs*/tmp>* <q.c
#include <stdio.h>
int main() {
int i=0;
printf("i=%d (outer)\n",i);
for (int i=1 /* inner */;i<2;i++) printf("i=%d (inner)\n",i);
printf("i=%d (outer again)\n",i);
return 0;
}
91 ocs*/tmp>* cc -Wall q.c && ./a.out
i=0 (outer)
i=1 (inner)
i=0 (outer again)
92 ocs*/tmp>*
===
Thanks and all the best,
OC
On 2 Dec 2020, at 17:34, Milles, Eric (TR Technology)
<eric.mil...@thomsonreuters.com
<mailto:eric.mil...@thomsonreuters.com>> 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
for (x in y index i) { // from Gosu
(http://gosu-lang.github.io/docs.html
<http://gosu-lang.github.io/docs.html>) -- an alternative to using
eachWithIndex
}
if (x instanceof T t) { // from Java 14+
}
if (def x = ...) { // tests Groovy truth in this form; may be wrapped
in parens to check something else about "x"
}
try (def ac = ...) {
}
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