From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2006-01-26 10:54:09
Elviin wrote:
> I'd like to use non-ast tree. I'm also using the tree_to_xml
> function to generate xml code.
> Plus my own grammar. The problem is with the token_node_d
> directive. I assumed that this directive merge the parsed
> code to an one node. At this time my parser works for me very
> fine except the tree because there are missing value objects
> in xml structure. So it seems that the whole tree is empty:/
>
> I can reproduce that state with the example file parse_tree_calc1.cpp:
IIRC, the token_node_d or leaf_node_d cannot be used with a rule inside the
[]. But I'm not sure anymore about the rationale behind this. I'm CC'ing to
Dan Nuffer, he's the original author of this code, perhaps he has some
additional information.
Regards Hartmut
>
> The correct output from the tree_to_xml function is following
> when parsing "1":
>
> <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE
> parsetree SYSTEM "parsetree.dtd">
> <!-- 1 -->
> <parsetree version="1.0">
> <parsenode rule="expression">
> <parsenode rule="term">
> <parsenode rule="factor">
> <parsenode rule="integer">
> <parsenode rule="integer">
> <value>1</value> <<<<======== it's OK here
> </parsenode>
> </parsenode>
> </parsenode>
> </parsenode>
> </parsenode>
> </parsetree>
> parsing succeeded
>
> ... and the corresponfing code/rules:
>
> integer = lexeme_d[ token_node_d[ (!ch_p('-') >>
> +digit_p) ] ];
> factor = integer
> | '(' >> expression >> ')'
> | ('-' >> factor);
> term = factor >>
> *( ('*' >> factor)
> | ('/' >> factor)
> );
> expression = term >>
> *( ('+' >> term)
> | ('-' >> term)
> );
>
>
>
>
> But if I move the token_node_d directive to another position,
> so that is similar to the problem with my grammar:
>
> integer = lexeme_d[ (!ch_p('-') >> +digit_p) ];
> factor = token_node_d[integer]
> | '(' >> expression >> ')'
> | ('-' >> factor);
> term = factor >>
> *( ('*' >> factor)
> | ('/' >> factor)
> );
> expression = term >>
> *( ('+' >> term)
> | ('-' >> term)
> );
>
>
> ... then the XML structure looks like this. The "value"
> object are missing:
>
> <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE
> parsetree SYSTEM "parsetree.dtd">
> <!-- 1 -->
> <parsetree version="1.0">
> <parsenode rule="expression">
> <parsenode rule="term">
> <parsenode rule="factor">
> <parsenode rule="integer">
>
> <<<<======== it is not OK here
> </parsenode>
> </parsenode>
> </parsenode>
> </parsenode>
> </parsetree>
> parsing succeeded
>
>
> Can anyone explain me why it is not possible to use the
> directive token_node_d like this token_node_d[integer]? I
> just want to group all the parsed text (integer) in one node.
> May I have to change the policy or to create proper typedefs.
>
> The problem is with hierarchy, that I want to group the
> parsed text only in the higher levels of parsing process.
>
> Thank you.
>
> Elviin
>
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