Antlr4导入的组合语法失败 [英] Antlr4 import of combined grammar failing
问题描述
我现在正在......
错误(56):AqlCommentTest.g4:12:4:未定义的引用规则:htmlCommentDeclaration
错误(56):AqlCommentTest.g4:13:4:对未定义规则的引用:mdCommentDeclaration
词法分析器语法的导入似乎正在加载。
以下文件显示问题。
AqlCommentTest.g4
语法AqlCommentTest;
import AqlLexerRules;
import AqlComment;
程序:commentDeclaration +;
commentDeclaration:
htmlCommentDeclaration #Comment_HTML
| mdCommentDeclaration #Comment_MD
;
AqlComment.g4
语法AqlComment;
import AqlLexerRules;
htmlCommentDeclaration:'html''{''(*'STRING'*)''}';
mdCommentDeclaration:'md''{''(*'STRING'*)''}';
AqlLexerRules.g4
lexer语法AqlLexerRules;
STRING:'''[a-z]?''';
可以通过从'AqlCommentTest.g4'文件中删除'import AqlLexerRules;'来停止错误。
为什么这会修复这个问题?
如何检查是否以及如何antlr4 import语句实际应用了吗?
如果导入词法分析器规则是最后一次:
import AqlComment;
import AqlLexerRules;
错误更改为:
错误(54):AqlCommentTest.g4:4:0:重复语法前缀规范(选项,标记或导入);请合并
因此问题:是否有关于导入的限制?
在明确的ANTLR 4参考 15.2语法结构或 doc :
每个选项,导入和令牌规范最多只能有一个。
如果我将导入更改为:
import AqlComment,AqlLexerRules;
它编译。</ p>
I am presently getting...
error(56): AqlCommentTest.g4:12:4: reference to undefined rule: htmlCommentDeclaration
error(56): AqlCommentTest.g4:13:4: reference to undefined rule: mdCommentDeclaration
The import for the lexer grammar does seem to be loading. The following files present the problem.
AqlCommentTest.g4
grammar AqlCommentTest;
import AqlLexerRules;
import AqlComment;
program: commentDeclaration+;
commentDeclaration:
htmlCommentDeclaration #Comment_HTML
| mdCommentDeclaration #Comment_MD
;
AqlComment.g4
grammar AqlComment;
import AqlLexerRules;
htmlCommentDeclaration: 'html' '{' '(*' STRING '*)' '}';
mdCommentDeclaration: 'md' '{' '(*' STRING '*)' '}';
AqlLexerRules.g4
lexer grammar AqlLexerRules;
STRING : '"' [a-z]? '"' ;
The errors can be stopped by removing the 'import AqlLexerRules;' from the 'AqlCommentTest.g4' file.
Why does this "fix" the problem?
How can I check to see if and how an antlr4 import statement is actually applied?
If the import lexer rules comes last :
import AqlComment;
import AqlLexerRules;
the error changes to :
error(54): AqlCommentTest.g4:4:0: repeated grammar prequel spec (options, tokens, or import); please merge
Hence the question : is there a constraint about import ?
In the Definitive ANTLR 4 Reference 15.2 Grammar Structure or doc you can find :
There can be at most one each of options, imports, and token specifications.
If I change the import to :
import AqlComment, AqlLexerRules;
it compiles.
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