This class implements a simple bottom up parser.
This class may be used as base class for specialized parsers,
i.e. to parse Tk commands of different flavours.
use bottomUpParser;
my $p = bottomUpParser->new(<options>);
$self->parse(<options>);
$self->expected(<list of expected results>);
- Base structure
-
Constructor blesses a variable of type HASH.
- Class member
-
None
- Data member
-
-tokenList
-tree
-expected
-result
- Properties
-
expected ref to the expected token structure
production iterator to the production (reduce step)
result parsed token structure
tree ref to definition tree of the expected tokens
- Constructor
-
new (<options)
whereby options is
-tokenList, <ref to array>,
-tree , <ref to array>,
-production <callback>
- Destructor
-
destroy
- Methods
-
import import the constants to the caller' s package
tokenList list of the input stream (token)
new constructor
init instance initiator
parse parse process
optlistMandatory process element of an optional token list (shift step)
optlistOptional process element of an mandatory token list (shift step)
Author: Marco
date: 18.04.2009
History
18.04.2009 first draft
24.04.2009 version 1.02
30.12.2009 version 1.03
01.12.2009 version 1.04
Import the constants in the client's name space
Imported constants are
NOTHING
NEXTTOKEN
SHIFT
REDUCE
TRYNEXTDEF
TRYAGAIN
RETURN
DONE
SHIFTANDREDUCE
REDUCEANDSHIFT
ALL
OPTLISTOPTIONAL
OPTLISTMANDATORY
This sub is used to 'import' the constants
in the class package itself.
This method copies the tokenlist into a local array
and save a ref to it into the property tokenList.
Instantiate a new parser object.
This method initialize the data members of instance.
Therefore, it takes the same arglist as the constructor.
This method parses recursively the tokenlist and
returns the list of the parsed tokens which are saved
while the shift steps.
This is a minimal handler for a list element.
It return true if the element is valid, and
false when the end of list is encountered.
TODO : check the existence of the list.
This is a minimal handler for a list element.
It return true if the element is valid, and
false when the end of list is encountered.
