Programming Perl, 4th Edition

our

our TYPE EXPR : ATTRIBUTES
our EXPR : ATTRIBUTES
our TYPE EXPR
our EXPR

An our declares one or more variables to be valid globals within the enclosing block, file, or eval. That is, our has the same rules as a my declaration for determination of visibility, but does not create a new private variable; it merely allows unfettered access to the existing package global. If more than one value is listed, the list must be placed in parentheses.

The primary use of an our declaration is to hide the variable from the effects of a use strict "vars" declaration; since the variable is masquerading as a my variable, you are permitted to use the declared global variable without qualifying it with its package. However, just like the my variable, this only works within the lexical scope of the our declaration. In this respect, it differs from use vars, which affects the entire package and is not lexically scoped.

our is also like my in that you are allowed to declare variables with a TYPE and with ATTRIBUTES. Here is the syntax:

our Dog $spot :ears(short) :tail(long);

As of this writing, it’s not entirely clear what that will mean. Attributes could affect either the global or the local interpretation of $spot. On the one hand, it would be most like my variables for attributes to warp the current local view of $spot without interfering with other views of the global in other places. On the other hand, if one module declares $spot to be a Dog, and another declares $spot to be a Cat, you could end ...