帕尔和亲爱的社区,
首先,我要感谢你们惊人的Antlr4(以及作为整体的antlr :-))。 我在过去的6个月里一直在使用Antlr 3(我已经非常高兴了)但是我对antlr4更开心。我注意到使用java作为目标语言在语法简单性和生成时间方面有了很大的改进。 不幸的是,我对antlr3没有的运行时性能有一些顾虑。
这里是我语法的摘录:
declare_specs
:
DECLARE? declare_spec+
|
DECLARE
;
declare_spec
:
constant_declaration
| variable_declaration
| exception_declaration
| procedure_body
| function_body
;
这里生成的代码(我添加了System.out.println进行跟踪):
public final Declare_specsContext declare_specs() throws RecognitionException {
System.out.println("TIME: " + timestamp() + " - declare_specs - 1");
Declare_specsContext _localctx = new Declare_specsContext(_ctx, getState());
System.out.println("TIME: " + timestamp() + " - declare_specs - 2");
enterRule(_localctx, 118, RULE_declare_specs);
System.out.println("TIME: " + timestamp() + " - declare_specs - 3");
int _la;
try {
int _alt;
System.out.println("TIME: " + timestamp() + " - declare_specs - 4");
setState(826);
System.out.println("TIME: " + timestamp() + " - declare_specs - 5");
switch ( getInterpreter().adaptivePredict(_input,69,_ctx) ) {
case 1:
System.out.println("TIME: " + timestamp() + " - declare_specs - 6");
enterOuterAlt(_localctx, 1);
System.out.println("TIME: " + timestamp() + " - declare_specs - 7");
{
if (f_trace >= f_trace_low) {
System.out.println("TIME: " + timestamp() + " - DECLARE_SPECS - FIRST ALT");
};
setState(817);
System.out.println("TIME: " + timestamp() + " - declare_specs - 8");
_la = _input.LA(1);
System.out.println("TIME: " + timestamp() + " - declare_specs - 9");
if (_la==DECLARE) {
{
setState(816); match(DECLARE);
}
}
System.out.println("TIME: " + timestamp() + " - declare_specs - 10");
setState(820);
System.out.println("TIME: " + timestamp() + " - declare_specs - 11");
_errHandler.sync(this);
System.out.println("TIME: " + timestamp() + " - declare_specs - 12");
_alt = getInterpreter().adaptivePredict(_input,68,_ctx);
System.out.println("TIME: " + timestamp() + " - declare_specs - 13");
do {
switch (_alt) {
case 1:
{
{
System.out.println("TIME: " + timestamp() + " - declare_specs - 14");
setState(819);
System.out.println("TIME: " + timestamp() + " - declare_specs - 15");
declare_spec();
System.out.println("TIME: " + timestamp() + " - declare_specs - 16");
}
}
break;
default:
throw new NoViableAltException(this);
}
System.out.println("TIME: " + timestamp() + " - declare_specs - 17");
setState(822);
System.out.println("TIME: " + timestamp() + " - declare_specs - 18");
_errHandler.sync(this);
System.out.println("TIME: " + timestamp() + " - declare_specs - 19");
_alt = getInterpreter().adaptivePredict(_input,68,_ctx);
System.out.println("TIME: " + timestamp() + " - declare_specs - 20");
} while ( _alt!=2 && _alt!=-1 );
}
break;
case 2:
enterOuterAlt(_localctx, 2);
{
if (f_trace >= f_trace_low) {
System.out.println("TIME: " + timestamp() + " - DECLARE_SPECS - SECOND ALT");
};
setState(825); match(DECLARE);
}
break;
}
}
catch (RecognitionException re) {
_localctx.exception = re;
_errHandler.reportError(this, re);
_errHandler.recover(this, re);
}
finally {
exitRule();
}
return _localctx;
}
这里的痕迹:
................
TIME: 2013-02-06 09:47:10.417 - declare_specs - 12
TIME: 2013-02-06 09:47:11.023 - declare_specs - 13
.................
TIME: 2013-02-06 09:51:38.915 - DECLARE_SPEC - AFTER
.................
TIME: 2013-02-06 09:51:38.916 - declare_specs - 19
TIME: 2013-02-06 09:52:31.435 - declare_specs - 20
...................
TIME: 2013-02-06 09:52:31.435 - DECLARE_SPEC - INIT
我在调用_alt = getInterpreter()时失去了60''。adaptive adaptiveinput,_input,68,_ctx);第二次但是在调用_alt = getInterpreter()时小于1'.adaptivePredict(_input,68,_ctx);第一次。 更改的当然是参数_input和_ctx。
问题很可能在于我的语法,但我在我的智慧结束;-)。 你可以告诉我在哪里寻找解决方案。 2.无论如何,adaptivePredict正在发生什么; - )
感谢您的帮助!
亲切的问候,WolfgangHämmer
答案 0 :(得分:0)
听起来你的语法决定需要大量的前瞻和/或模糊或上下文敏感。不幸的是,如果没有看到完整的语法,我们将无法告诉你哪一个。您可以做的是以下内容,它将向控制台打印出有关歧义的详细信息。
parser.addErrorListener(new DiagnosticErrorListener());
parser.getInterpreter().setPredictionMode(PredictionMode.LL_EXACT_AMBIG_DETECTION);