ANTLR:“在规则范围上缺少属性访问".问题
我正在尝试建立一个ANTLR语法来解析带标记的句子,例如:
I am trying to build an ANTLR grammar that parses tagged sentences such as:
DT The NP cat VB ate DT a NP rat
并具有语法:
fragment TOKEN : (('A'..'Z') | ('a'..'z'))+;
fragment WS : (' ' | '\t')+;
WSX : WS;
DTTOK : ('DT' WS TOKEN);
NPTOK : ('NP' WS TOKEN);
nounPhrase: (DTTOK WSX NPTOK);
chunker : nounPhrase {System.out.println("chunk found "+"("+$nounPhrase+")");};
语法生成器在最后一行生成"missing attribute access on rule scope: nounPhrase
".
The grammar generator generates the "missing attribute access on rule scope: nounPhrase
" in the last line.
[我对ANTLR还是陌生的,尽管某些语法可以工作,但仍然是反复试验.运行如此小的语法时,我也会经常收到"OutOfMemory"错误-欢迎您提供帮助.]
[I am still new to ANTLR and although some grammars work it's still trial and error. I also frequently get an "OutOfMemory" error when running grammars as small as this - any help welcome.]
我正在使用ANTLRWorks 1.3生成代码并在Java 1.6下运行.
I am using ANTLRWorks 1.3 to generate the code and am running under Java 1.6.
找到更好的方法后正在回答问题...
Answering question after having found a better way...
WS : (' '|'\t')+;
TOKEN : (('A'..'Z') | ('a'..'z'))+;
dttok : 'DT' WS TOKEN;
nntok : 'NN' WS TOKEN;
nounPhrase : (dttok WS nntok);
chunker : nounPhrase ;
问题是我在词法分析器和解析器之间陷入混乱(这显然很常见).在解析器中,大写字母是词法,小写字母.现在,这似乎可行. (注意,我已将NP更改为NN).
The problem was I was getting muddled between the lexer and the parser (this is apparently very common). The uppercase items are lexical, the lowercase in the parser. This now seems to work. (NB I have changed NP to NN).