第一个问题流
大家好，
这可能是对这个问题的跟进：Antlr rule priority
我正在尝试为reStructuredText 标记语言编写 ANTLR 语法。
我面临的主要问题是：“如何匹配任何字符序列（常规文本）而不掩盖其他语法规则？”
让我们以一个带有内联标记的段落为例：
In `Figure 17-6`_, we have positioned ``before_ptr`` so that it points to the element
*before* the insert point. The variable ``after_ptr`` points to the element *after* the
insert. In other words, we are going to put our new element **in between** ``before_ptr``
and ``after_ptr``.
我认为为内联标记文本编写规则会很容易。所以我写了一个简单的语法：
grammar Rst;
options {
output=AST;
language=Java;
backtrack=true;
//memoize=true;
}
@members {
boolean inInlineMarkup = false;
}
// PARSER
text
: inline_markup (WS? inline_markup)* WS? EOF
;
inline_markup
@after {
inInlineMarkup = false;
}
: {!inInlineMarkup}? (emphasis|strong|litteral|link)
;
emphasis
@init {
inInlineMarkup = true;
}
: '*' (~'*')+ '*' {System.out.println("emphasis: " + $text);}
;
strong
@init {
inInlineMarkup = true;
}
: '**' (~'*')+ '**' {System.out.println("bold: " + $text);}
;
litteral
@init {
inInlineMarkup = true;
}
: '``' (~'`')+ '``' {System.out.println("litteral: " + $text);}
;
link
@init {
inInlineMarkup = true;
}
: inline_internal_target
| footnote_reference
| hyperlink_reference
;
inline_internal_target
: '_`' (~'`')+ '`' {System.out.println("inline_internal_target: " + $text);}
;
footnote_reference
: '[' (~']')+ ']_' {System.out.println("footnote_reference: " + $text);}
;
hyperlink_reference
: ~(' '|'\t'|'\u000C'|'_')+ '_' {System.out.println("hyperlink_reference: " + $text);}
| '`' (~'`')+ '`_' {System.out.println("hyperlink_reference (long): " + $text);}
;
// LEXER
WS
: (' '|'\t'|'\u000C')+
;
NEWLINE
: '\r'? '\n'
;
这个简单的语法是行不通的。而且我什至没有尝试匹配常规文本...
我的问题：
- 有人可以指出我的错误，并可能给我一个关于如何匹配常规文本的提示吗？
- 有没有办法设置语法规则的优先级？也许这可能是一个线索。
在此先感谢您的帮助 ：-）
罗宾
第二个问题流
非常感谢您的帮助！我很难弄清楚我的错误...我不是（仅）编写该语法来学习 ANTLR，我正在尝试为 Eclipse 编写一个 IDE 插件。为此，我需要一个语法；）
我设法在语法上走得更远，并写了一条text规则：
grammar Rst;
options {
output=AST;
language=Java;
}
@members {
boolean inInlineMarkup = false;
}
//////////////////
// PARSER RULES //
//////////////////
file
: line* EOF
;
line
: text* NEWLINE
;
text
: inline_markup
| normal_text
;
inline_markup
@after {
inInlineMarkup = false;
}
: {!inInlineMarkup}? {inInlineMarkup = true;}
(
| STRONG
| EMPHASIS
| LITTERAL
| INTERPRETED_TEXT
| SUBSTITUTION_REFERENCE
| link
)
;
link
: INLINE_INTERNAL_TARGET
| FOOTNOTE_REFERENCE
| HYPERLINK_REFERENCE
;
normal_text
: {!inInlineMarkup}?
~(EMPHASIS
|SUBSTITUTION_REFERENCE
|STRONG
|LITTERAL
|INTERPRETED_TEXT
|INLINE_INTERNAL_TARGET
|FOOTNOTE_REFERENCE
|HYPERLINK_REFERENCE
|NEWLINE
)
;
//////////////////
// LEXER TOKENS //
//////////////////
EMPHASIS
: STAR ANY_BUT_STAR+ STAR {System.out.println("EMPHASIS: " + $text);}
;
SUBSTITUTION_REFERENCE
: PIPE ANY_BUT_PIPE+ PIPE {System.out.println("SUBST_REF: " + $text);}
;
STRONG
: STAR STAR ANY_BUT_STAR+ STAR STAR {System.out.println("STRONG: " + $text);}
;
LITTERAL
: BACKTICK BACKTICK ANY_BUT_BACKTICK+ BACKTICK BACKTICK {System.out.println("LITTERAL: " + $text);}
;
INTERPRETED_TEXT
: BACKTICK ANY_BUT_BACKTICK+ BACKTICK {System.out.println("LITTERAL: " + $text);}
;
INLINE_INTERNAL_TARGET
: UNDERSCORE BACKTICK ANY_BUT_BACKTICK+ BACKTICK {System.out.println("INLINE_INTERNAL_TARGET: " + $text);}
;
FOOTNOTE_REFERENCE
: L_BRACKET ANY_BUT_BRACKET+ R_BRACKET UNDERSCORE {System.out.println("FOOTNOTE_REFERENCE: " + $text);}
;
HYPERLINK_REFERENCE
: BACKTICK ANY_BUT_BACKTICK+ BACKTICK UNDERSCORE {System.out.println("HYPERLINK_REFERENCE (long): " + $text);}
| ANY_BUT_ENDLINK+ UNDERSCORE {System.out.println("HYPERLINK_REFERENCE (short): " + $text);}
;
WS
: (' '|'\t')+ {$channel=HIDDEN;}
;
NEWLINE
: '\r'? '\n' {$channel=HIDDEN;}
;
///////////////
// FRAGMENTS //
///////////////
fragment ANY_BUT_PIPE
: ESC PIPE
| ~(PIPE|'\n'|'\r')
;
fragment ANY_BUT_BRACKET
: ESC R_BRACKET
| ~(R_BRACKET|'\n'|'\r')
;
fragment ANY_BUT_STAR
: ESC STAR
| ~(STAR|'\n'|'\r')
;
fragment ANY_BUT_BACKTICK
: ESC BACKTICK
| ~(BACKTICK|'\n'|'\r')
;
fragment ANY_BUT_ENDLINK
: ~(UNDERSCORE|' '|'\t'|'\n'|'\r')
;
fragment ESC
: '\\'
;
fragment STAR
: '*'
;
fragment BACKTICK
: '`'
;
fragment PIPE
: '|'
;
fragment L_BRACKET
: '['
;
fragment R_BRACKET
: ']'
;
fragment UNDERSCORE
: '_'
;
语法对于 inline_markup 工作正常，但 normal_text 不匹配。
这是我的测试课：
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import org.antlr.runtime.ANTLRStringStream;
import org.antlr.runtime.CommonTokenStream;
import org.antlr.runtime.RecognitionException;
import org.antlr.runtime.tree.Tree;
public class Test {
public static void main(String[] args) throws RecognitionException, IOException {
InputStream is = Test.class.getResourceAsStream("test.rst");
Reader r = new InputStreamReader(is);
StringBuilder source = new StringBuilder();
char[] buffer = new char[1024];
int readLenght = 0;
while ((readLenght = r.read(buffer)) > 0) {
if (readLenght < buffer.length) {
source.append(buffer, 0, readLenght);
} else {
source.append(buffer);
}
}
r.close();
System.out.println(source.toString());
ANTLRStringStream in = new ANTLRStringStream(source.toString());
RstLexer lexer = new RstLexer(in);
CommonTokenStream tokens = new CommonTokenStream(lexer);
RstParser parser = new RstParser(tokens);
RstParser.file_return out = parser.file();
System.out.println(((Tree)out.getTree()).toStringTree());
}
}
我使用的输入文件：
In `Figure 17-6`_, we have positioned ``before_ptr`` so that it points to the element
*before* the insert point. The variable ``after_ptr`` points to the |element| *after* the
insert. In other words, `we are going`_ to put_ our new element **in between** ``before_ptr``
and ``after_ptr``.
我得到这个输出：
HYPERLINK_REFERENCE (short): 7-6`_
line 1:2 mismatched character ' ' expecting '_'
line 1:10 mismatched character ' ' expecting '_'
line 1:18 mismatched character ' ' expecting '_'
line 1:21 mismatched character ' ' expecting '_'
line 1:26 mismatched character ' ' expecting '_'
line 1:37 mismatched character ' ' expecting '_'
LITTERAL: `before_ptr`
line 1:86 no viable alternative at character '\r'
line 1:55 mismatched character ' ' expecting '_'
line 1:60 mismatched character ' ' expecting '_'
line 1:63 mismatched character ' ' expecting '_'
line 1:70 mismatched character ' ' expecting '_'
line 1:73 mismatched character ' ' expecting '_'
line 1:77 mismatched character ' ' expecting '_'
line 1:85 mismatched character ' ' expecting '_'
EMPHASIS: *before*
line 2:12 mismatched character ' ' expecting '_'
line 2:19 mismatched character ' ' expecting '_'
line 2:26 mismatched character ' ' expecting '_'
LITTERAL: `after_ptr`
line 2:30 mismatched character ' ' expecting '_'
line 2:39 mismatched character ' ' expecting '_'
line 2:90 no viable alternative at character '\r'
line 2:60 mismatched character ' ' expecting '_'
line 2:63 mismatched character ' ' expecting '_'
line 2:67 mismatched character ' ' expecting '_'
line 2:77 mismatched character ' ' expecting '_'
line 2:85 mismatched character ' ' expecting '_'
line 2:89 mismatched character ' ' expecting '_'
line 3:7 mismatched character ' ' expecting '_'
line 3:10 mismatched character ' ' expecting '_'
line 3:16 mismatched character ' ' expecting '_'
line 3:23 mismatched character ' ' expecting '_'
line 3:27 mismatched character ' ' expecting '_'
line 3:31 mismatched character ' ' expecting '_'
line 3:42 mismatched character ' ' expecting '_'
line 3:51 mismatched character ' ' expecting '_'
line 3:55 mismatched character ' ' expecting '_'
line 3:63 mismatched character ' ' expecting '_'
line 3:94 mismatched character '\r' expecting '*'
line 4:3 mismatched character ' ' expecting '_'
line 4:18 no viable alternative at character '\r'
line 4:18 mismatched character '\r' expecting '_'
HYPERLINK_REFERENCE (short): oing`_
HYPERLINK_REFERENCE (short): ut_
EMPHASIS: *in between*
LITTERAL: `after_ptr`
BR.recoverFromMismatchedToken
line 0:-1 mismatched input '<EOF>' expecting NEWLINE
null
你能指出我的错误吗？（当我将 filter=true; 选项添加到语法时，解析器适用于内联标记而不会出错）
罗宾
