blocks|key|1320294|text|您需要为此创建自己的IAntlrErrorStrategy实现，然后将Parser.ErrorHandler属性设置为您的错误策略的一个实例。ANTLRErrorStrategy接口的Java版本和缺省实现DefaultErrorStrategy的文档可能会为实现错误策略提供有用的信息，但我必须警告您，创建自定义错误策略是一个高级功能，文档有限。预计实现者已经是ANTLR+4实现自适应LL(*)解析算法的专家(我们说的是研究人员级别的理解)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1320295|entityMap|0|LINK|mutability|MUTABLE|url|http://www.antlr.org/api/Java/org/antlr/v4/runtime/ANTLRErrorStrategy.html|1|http://www.antlr.org/api/Java/org/antlr/v4/runtime/DefaultErrorStrategy.html^0|A|J|Z|J|1Z|I|2V|K|1Z|I|0|2V|K|1|0^^$0|@$1|2|3|4|5|6|7|P|8|@$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]|$9|W|A|X|B|C]]|D|@$9|Y|A|Z|1|10]|$9|11|A|12|1|13]]|E|$]]|$1|F|3|-4|5|6|7|14|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]|N|$5|I|J|K|E|$L|O]]]]

You will need to create your own implementation of <code>IAntlrErrorStrategy</code> for this, and then set the <code>Parser.ErrorHandler</code> property to an instance of your error strategy. The documentation for the Java versions of the <a href="http://www.antlr.org/api/Java/org/antlr/v4/runtime/ANTLRErrorStrategy.html" rel="noreferrer"><code>ANTLRErrorStrategy</code></a> interface and default implementation <a href="http://www.antlr.org/api/Java/org/antlr/v4/runtime/DefaultErrorStrategy.html" rel="noreferrer"><code>DefaultErrorStrategy</code></a> may provide useful information for implementing an error strategy, but I must warn you going in that creating a custom error strategy is an advanced feature with limited documentation. It's expected that the implementer is already an expert in ANTLR 4's implementation of the Adaptive LL(*) parsing algorithm (we're talking researcher-level understanding).

blocks|key|1194102|text|对于第一个问题(如何将输入同步到下一个有效项？)我发现了一些有用的信息，这些信息让我找到了可以接受的解决方案。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1194103|Antlr为前面的语法生成下一个子代码：|1194104|public+TextContext+text()+{
++++TextContext+_localctx+=+new+TextContext(_ctx,+State);
++++EnterRule(_localctx,+0,+RULE_text);
++++int+_la;
++++try+{
++++++++EnterOuterAlt(_localctx,+1);
++++++++State+=+49;
++++++++_errHandler.Sync(this);
++++++++_la+=+_input.La(1);
++++++++do+{
++++++++++++State+=+48;+term();
++++++++++++State+=+51;
++++++++++++_errHandler.Sync(this);
++++++++++++_la+=+_input.La(1);
++++++++}+while+(+_la==KEYWORD+);
++++++++State+=+53;+Match(EOF);
++++}
++++catch+(RecognitionException+re)+{
++++++++_localctx.exception+=+re;
++++++++_errHandler.ReportError(this,+re);
++++++++_errHandler.Recover(this,+re);
++++}
++++finally+{
++++++++ExitRule();
++++}
++++return+_localctx;
}|code-block|syntax|javascript|1194105|调用'_errHandler.Sync(this);‘使解析器在输入流中前进，试图找到下一个有效的转折(作为"term%2B“组件的结果)。为了阻止解析器在其他接受"term“规则的子规则中同步，我将DefaultErrorStrategy类扩展为next：|1194106|public+class+MyErrorStrategy+:+Antlr4.Runtime.DefaultErrorStrategy
{
++++public+EventErrorStrategy()+:+base()
++++{+}

++++public+override+void+Sync(Antlr4.Runtime.Parser+recognizer)
++++{
++++++++if(recognizer.Context+is+Dict.TextAnalyzer.DictionaryParser.TextContext)
++++++++++++base.Sync(recognizer);
++++}
}|1194107|然后将其提供给解析器：|1194108|parser.ErrorHandler+=+new+MyErrorStrategy();|1194109|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|W|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

For the first question (How to synchronize input to the next valid term?) I found some useful information that led me to acceptable solution.

Antlr generates next subcode for previous grammar:

<pre><code>public TextContext text() {
 TextContext _localctx = new TextContext(_ctx, State);
 EnterRule(_localctx, 0, RULE_text);
 int _la;
 try {
 EnterOuterAlt(_localctx, 1);
 State = 49;
 _errHandler.Sync(this);
 _la = _input.La(1);
 do {
 State = 48; term();
 State = 51;
 _errHandler.Sync(this);
 _la = _input.La(1);
 } while ( _la==KEYWORD );
 State = 53; Match(EOF);
 }
 catch (RecognitionException re) {
 _localctx.exception = re;
 _errHandler.ReportError(this, re);
 _errHandler.Recover(this, re);
 }
 finally {
 ExitRule();
 }
 return _localctx;
}
</code></pre>

The call '_errHandler.Sync(this);' makes the parser advances through the input stream in an attempt to find next valid turn (as a result of "term+" component).
To stop parser from sync in other subrules accept "term" rule", I Extended DefaultErrorStrategy Class as next:

<pre><code>public class MyErrorStrategy : Antlr4.Runtime.DefaultErrorStrategy
{
 public EventErrorStrategy() : base()
 { }

 public override void Sync(Antlr4.Runtime.Parser recognizer)
 {
 if(recognizer.Context is Dict.TextAnalyzer.DictionaryParser.TextContext)
 base.Sync(recognizer);
 }
}
</code></pre>

then provided it to the parser:

<pre><code>parser.ErrorHandler = new MyErrorStrategy();
</code></pre>

I'm using Antlr 4 with c# target.
Here is a subset of my grammar:

<pre><code>/*
 * Parser Rules
 */
text : term+ EOF;
term : a1 a2 a3;
a1: ....
...
...
</code></pre>

I want to accept valid data blocks as (term)s, when error exists I want to search for the next valid term and print out the whole text which caused the error for user to analyze manually.

How to synchronize input to the next valid term? 
and How to get the ignored text?

How to control error handling and synchronization in Antlr 4 / c#

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我正在使用带有c#目标的Antlr4。下面是我的语法的一个子集：/* * Parser Rules */text : term+  EOF;term : a1 a2 a3;a1: ..........我想接受有效数据块作为(术语)s，当存在错误时，我想搜索下一个有效术语，并打印出导致错误的整个文本，供用户手动分析。如何...

问如何在Antlr4/ c#中控制错误处理和同步
EN

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