array_extending.t

useTest;

plan21;

# L<S09/Autovivification/In Raku these read-only operations are indeed non-destructive:>
{
# Compare with Perl:
# $ perl -we '
# my @array = qw<a b c>;
# my $foo = $array[100];
# print exists $array[30] ? "exists" : "does not exist"
# '
# does not exist
my@array= <a b c d>;
is+@array, 4, "basic sanity";
my$foo=@array[20];
# We've only *accessed* @array[20], but we haven't assigned anything to it, so
# @array shouldn't change. But currently, @array *is* automatically extended,
# i.e. @array is ("a", "b", "c", "d", Mu, Mu, ...). This is wrong.
is+@array, 4,
"accessing a not existing array element should not automatically extend the array";
}

{
my@array= <a b c d>;
@array[20] =42;
# Now, we did assign @array[20], so @array should get automatically extended.
# @array should be ("a", "b", "c", "d", Mu, Mu, ..., 42).
is+@array, 21,
"creating an array element should automatically extend the array (1)";
# And, of course, @array[20]:exists has to be true -- we've just assigned
# @array[20].
ok@array[20]:exists,
"creating an array element should automatically extend the array (2)";
}

{
my@array= <a b c d>;
my$defined=defined@array[100];

ok!$defined,
'defined @array[$index_out_of_bounds] should be false';
is+@array, 4,
'defined @array[$index_out_of_bounds] should not have altered @array';
}

{
my@array= <a b c d>;
my$defined;
try { $defined=defined@array[*-5]; }

ok!$defined,
'defined @array[$negative_index_out_of_bounds] should be false';
is+@array, 4,
'defined @array[$negative_index_out_of_bounds] should not have altered @array';
}

{
my@array= <a b c d>;
my$exists=@array[100]:exists;

ok!$exists,
'@array[$index_out_of_bounds]:exists should be false';
is+@array, 4,
'@array[$index_out_of_bounds]:exists should not have altered @array';
}

{
my@array= <a b c d>;
my$exists=@array[*-5]:exists;

ok!$exists,
'@array[$negative_index_out_of_bounds]:exists should be false';
is+@array, 4,
'@array[$negative_index_out_of_bounds]:exists should not have altered @array';
}

{
my@a;
@a[2] =6;
is+@a, 3, '@a[2] = 6 ensures that @a has three items';
nok@a[0].defined, '... and the first is not defined';
nok@a[1].defined, '... and the second is not defined';
is@a[2], 6, '... and the third is 6';
}

# https://github.com/Raku/old-issue-tracker/issues/669
{
my@a;
@a[2] ='b';
my@b=@a;
is+@b, 3, 'really a degenerative case of assigning list to array';
@b=flat (6, @a);
is+@b, 4, 'assigning list with extended array to an array';
my$s=@a.join(':');
is$s, '::b', 'join on extended array';
my$n=+@a.grep({ $_eq'b'});
is$n, 1, 'grep on extended array';
@a[1] ='c'; # cmp doesn't handle Mu cmp Mu yet
is@a.min(), 'b', 'min on list with undefined el ignores it';
}

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