The ConfigReader library is a set of classes which reads directives from a configuration file. The library is completely object oriented, and it is envisioned that parsers for new styles of configuration files can be easily added.
ConfigReader::Spec encapsulates a specification for configuration directives. You can specify which directives can be in the configuration file, aliases for the directive, whether the directive is required or has a default value, and how to parse the directive value.
Here's an example of how one directive might be specified:
required $spec 'HomePage', 'new URI::URL';
This defines a required directive called 'HomePage'. To parse the value from the configuration file, the URI::URL::new() method will be called with the string value as its argument.
If the directive name is a simple string, it will be used both to refer to the directive in the Perl program, and as the name in the configuration file. You can also specify an alias by using an array ref. For example, suppose you wanted to use “index” as the name of the directive in the configuration file, but to avoid confusion with Perl's index() function you wanted to refer to the directive inside the program as the “file_index”. This will do the trick:
You can specify any number of aliases for the directive:
['file_index', 'index', 'file_index', 'contents', ...]
The parsing function or method is called to translate the value string from the configuration file into the value used by the program. It can be specified in several different ways:
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You can also specify a default value to be used if a directive is not specified in the configuration file.
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ConfigReader::Values stores a set of directive values that have been read from a configuration file. It stores a reference to an associated Spec as a member variable. Separating the specification from the values makes it possible to use a single specification for multiple sets of values.
ConfigReader::DirectiveStyle implements a reader for a common style of configuration file. It is a subclass of ConfigReader::Values. Directive names are followed by their value, one per line:
HomePage http://www.w3.org/ Services /etc/services