Tie::Scalar
See the current Perl documentation for Tie::Scalar.
Here is our local, out-dated (pre-5.6) version:
Tie::Scalar, Tie::StdScalar - base class definitions for tied scalars
package NewScalar; require Tie::Scalar; @ISA = (Tie::Scalar); sub FETCH { ... } # Provide a needed method sub TIESCALAR { ... } # Overrides inherited method package NewStdScalar
This module provides some skeletal methods for scalar-tying classes. See perltie for a list of the functions required in tying a scalar to a package. The basic Tie::Scalar package provides a
new
method, as well as methodsTIESCALAR
,FETCH
andSTORE
. The Tie::StdScalar package provides all the methods specified in perltie. It inherits from Tie::Scalar and causes scalars tied to it to behave exactly like the built-in scalars, allowing for selective overloading of methods. Thenew
method is provided as a means of grandfathering, for classes that forget to provide their ownTIESCALAR
method.For developers wishing to write their own tied-scalar classes, the methods are summarized below. The perltie section not only documents these, but has sample code as well:
- TIESCALAR classname, LIST
-
The method invoked by the command
tie $scalar, classname
. Associates a new scalar instance with the specified class.LIST
would represent additional arguments (along the lines of AnyDBM_File and compatriots) needed to complete the association. - FETCH this
- Retrieve the value of the tied scalar referenced by this.
- STORE this, value
- Store data value in the tied scalar referenced by this.
- DESTROY this
- Free the storage associated with the tied scalar referenced by this. This is rarely needed, as Perl manages its memory quite well. But the option exists, should a class wish to perform specific actions upon the destruction of an instance.
MORE INFORMATION
The perltie section uses a good example of tying scalars by associating process IDs with priority.