Question

我正在重新实现ANTLR4中的现有DSL。现有的源体有一些非常大的表达式。似乎ALL（*）逻辑中的递归意味着我可以解析的表达式有多大限制。

示例语法:(刚好足以在此处重现错误错误）

  grammar A4Test;

  fragment DIGIT : [0-9];

  fragment ALPHA : [a-zA-Z];


  WS  :   [ \t\r\n\u000D'] {skip();};

  ID  :   ALPHA (ALPHA|DIGIT)*;

  NUMBER : '-'?(DIGIT+|(DIGIT*'.'DIGIT+));

  e : expr;

  expr : '(' expr ')'
    |   expr 'OR' expr
    |   expr 'AND' expr
    |   ID
    |   NUMBER
    ;

示例输入：

V0 AND 0 OR
V1 AND 1 OR
...  (MANY rows elided)
V3999 AND 3999 OR
V4000 AND 4000

堆栈追踪：

Exception in thread "main" java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.antlr.v4.runtime.misc.TestRig.process(TestRig.java:249)
    at org.antlr.v4.runtime.misc.TestRig.process(TestRig.java:211)
    at org.antlr.v4.runtime.misc.TestRig.main(TestRig.java:143)
Caused by: java.lang.StackOverflowError
    at java.util.Arrays.equals(Arrays.java:1869)
    at org.antlr.v4.runtime.atn.ArrayPredictionContext.equals(ArrayPredictionContext.java:101)
    at java.util.HashMap.getEntry(HashMap.java:471)
    at java.util.LinkedHashMap.get(LinkedHashMap.java:301)
    at org.antlr.v4.runtime.misc.DoubleKeyMap.get(DoubleKeyMap.java:62)
    at org.antlr.v4.runtime.atn.PredictionContext.mergeArrays(PredictionContext.java:418)
    at org.antlr.v4.runtime.atn.PredictionContext.merge(PredictionContext.java:199)
    at org.antlr.v4.runtime.atn.ATNConfigSet.add(ATNConfigSet.java:175)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closure_(ParserATNSimulator.java:1126)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closureCheckingStopState(ParserATNSimulator.java:1111)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closure_(ParserATNSimulator.java:1164)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closureCheckingStopState(ParserATNSimulator.java:1111)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closure_(ParserATNSimulator.java:1164)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closureCheckingStopState(ParserATNSimulator.java:1111)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closure_(ParserATNSimulator.java:1164)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closureCheckingStopState(ParserATNSimulator.java:1111)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closure_(ParserATNSimulator.java:1164)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closureCheckingStopState(ParserATNSimulator.java:1111)
    at org.antlr.v4.runtime.atn.ParserATNSimulator.closure_(ParserATNSimulator.java:1164)

...

限制表达式的大小不是一种选择。他们使用当前的技术编译得很好，所以我们必须支持它。

我是否必须将左递归分解为此以避免极高的堆栈利用率？或者，有一个更简单的答案吗？

Answer 1

ANTLR 4.2将通过合并pull request #401来改善这种情况。由于它还没有发布，我建议从源代码构建最新版本的ANTLR 4并再次尝试输入。

堆栈溢出解析ANTLR4中的非常大的表达式

1 个答案: