CODEWITHSUNDEEP
variablesdeclareraku
lisprogtor
lisprogtor

Reputation: 5749

why can't perl6 just autovivify so that I don't have to use "my" all the time?

In per5, I can just use a variable, such as $foo or @bar without using "my".

$foo=1; @bar=(1,2);

In perl6, why do I have to use "my" all the time? Otherwise compiler will say variable undeclared.Why can't perl6 just autovivify?

print "{my @a=1,2,3;}\n"; # have to use "my" to declare variable
print "{@a=1,2,3;}\n"; # this is error 'Variable '@a' is not declared'

I don't like the restriction of having to always use "my". This is too low level like C; very cumbersome.

Is there a way to turn on always autovivify?

Thanks.

Upvotes: 3

Views: 113

Answers (2)

user5854207
user5854207

Reputation: 

no strict;
$foo=1; @bar=(1,2);
print "{@a=1,2,3;}\n";
# OUTPUT«1 2 3␤»

Perl 6 tries to help you with proper error messages. If you declare all variables it will provide you with a guess what variable you meant if you have a typo. Also there are new language features like constants and sigilless variables that are not possible to write down without declarators.

Upvotes: 4

Christoph
Christoph

Reputation: 169623

Not having explicit variable declarations is a terrible idea from the perspective of language design for various reasons. Arguably, explicitly declared block-scoped lexical variables are the way to go, and I find it crazy how many languages of the 'scripting' variety get this 'wrong' (there's a reason why let got added to Javascript...)

That said, Perl6 supports the no strict pragma which allows you to omit the declaration.

Upvotes: 10

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