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,

On 2 Dec 2020, at 17:34, Milles, Eric (TR Technology) <eric.milles@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) -- 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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