Package pobs

Interfaces and basic classes of the framework.

See:
Description

Interface Summary

PAction	Interface which allows semantic actions to be linked to parsers.
PControl	Interface of all classes which manipulate PDirective.
PErrorHandler	Interface of all error handlers.
PObject	Defines the method signature required to link Parser OBjectS together.
PScanner	Provides the standard interface to which all iterators must conform.
PTarget	Marks a target for actions .

Class Summary

PContext	Immutable class containg a PDirective instance and optional a PTarget and a PErrorHandler.
PDirective	Maintains all state information for the POBS framework such as parser policies.
PMatch	Immutable class which contains information on success/failure and the length/point-of-failure of a parse.
PParser	Abstract base class of all parsers.

Package pobs Description

Interfaces and basic classes of the framework.

PParser is the central class of POBS. All concrete parsers extend this abstract class. In package pobs.parser small concrete general-purpose parsers are defined. To create your own parser you just use these predefined parsers as building block. They are defined in such a way that it is easy to build a parser from an (E)BNF syntax definition.

The following class diagram gives an overview of the architecture of the framework:

After parsing a parser returns a PMatch instance which tells whether parsing was successful or not. One can attach a PAction for both cases.

For parsing a parser needs a PScanner which capsulates the source to be parsed and a PContext. The parser context holds

• a PDirective object giving directives for parsing (e.g. do case-sensitive parsing or not),
• an optional PTarget manipulated by actions,
• an optional PErrorHandler which will be notified by the parser in case of unsuccessful parsing.

One can add PControl objects to a parser. They modify the PDirective object before parsing.