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4. AN IMPLEMENTATION 4.4. Data Structures
InternalParser
'()*+,-#".+()&/+0%
!"#$%#&!
!"#$%#&"
Figure 4.1: Recognition of a configuration file by two parsers
InternalParser (Listing 4.3) objects represent parsers generated by the tool, through the
Grammar Compiler. An InternalParser object contains a pointer to the parse method
and the grammar used to construct the parser.
Regarding the parse method, the latter is invoked resorting to the Java reflex API and re-
turns a list of Node objects (Listing 4.1) due to be transformed to XML by the
Code Generator.
Concerning the grammar used for the generation of the InternalParser, it is kept with
the parser in order to aid users on the generation of new parsers. Consider the case where a
user tries to configure a file which is new to the tool and two parsers are stored. The result of
the parsing attempt is depicted in Figure 4.1.
In the example, two parsers are tested on a configuration file with 100 lines. The first parser,
α, manages to recognize the file from line 0 to 59 and then from line 70 to 99, resulting in a 90%
of parsed file. On the other hand, parser β recognized 20% of the file, from line 50 to 69.
In this situation, the user who would build the new parser for the file might want to access
the grammar of the parser α, since it parsed almost the entire file, and base the new parser on
the old instead of starting from scratch. Also, seen as the second parser recognized the part of
the file that the first did not, the user might want to check the grammar of the second parser.
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