using constant array

[A. Farber]

Hi,

I have defined a list of constants in my script:

use constant DEFPLATS => qw(ARMI ARM4 THUMB WINS WINSCW);

But the use of it feels a bit clumsy though -
I have to put it in brackets for the hash slices:

@prj_platforms{(DEFPLATS)} = (1) x length DEFPLATS;

and it doesn't interpolate in strings.
Do you have any advices on that? TIA

Regards
Alex

 

[Ben Morrow]

Quoth (e-mail address removed) (A. Farber):

I have defined a list of constants in my script:

use constant DEFPLATS => qw(ARMI ARM4 THUMB WINS WINSCW);

But the use of it feels a bit clumsy though -
I have to put it in brackets for the hash slices:

@prj_platforms{(DEFPLATS)} = (1) x length DEFPLATS;

You don't have to, you just have to make it not a bareword:

@hash{DEFPLATS()}
@hash{+DEFPLATS}

and it doesn't interpolate in strings.

You can interpolate a sub with

my $str = "stuff @{[ DEFPLATS ]} stuff"

However, I think both your problems are better solved by simply using an
array:

my @DEFPLATS = qw/.../;

or, if you need it to be package- rather than lexically-scoped, like the
constant was,

our @DEFPLATS = qw/.../;

If you need it at compile time you can do the slightly clumsy

my @DEFPLATS;
BEGIN { @DEFPLATS = qw/.../ }

or, if you are package-scoping it,

use vars::i '@DEFPLATS' => qw/.../;

Get vars::i from CPAN.

Ben

 

[Tad McClellan]

I have defined a list of constants in my script:

use constant DEFPLATS => qw(ARMI ARM4 THUMB WINS WINSCW);

and it doesn't interpolate in strings.

Constants defined using this module cannot be interpolated
into strings like variables.

Do you have any advices on that?

What "that"? It does exactly what it says it will do.

If that isn't want you want, then do something else. <g>


perldoc constant

 

[Tad McClellan]

use constant DEFPLATS => qw(ARMI ARM4 THUMB WINS WINSCW);

I have to put it in brackets for the hash slices:

@prj_platforms{(DEFPLATS)} = (1) x length DEFPLATS;

That supplies a list context, which will keep "use warnings" quiet.

You can put the parenthesis elsewhere if you like it better (I do):

@prj_platforms{ DEFPLATS() } = (1) x length DEFPLATS;

(whitespace is your friend if used wisely.)



Also, length() no worky on lists (nor arrays):

perldoc -f length