StackOverflowError in ANTLR4

Question

我对ANTLR很陌生，并且尝试解析一个ASP文件。我在走树的时候遇到了错误。

org.antlr.v4.runtime.atn.LexerATNSimulator.getEpsilonTarget(LexerATNSimulator.java:495) at org.antlr.v4.runtime.atn.LexerATNSimulator.closure(LexerATNSimulator.java:476) at org.antlr.v4.runtime.atn.LexerATNSimulator.closure(LexerATNSimulator.java:478) at org.antlr.v4.runtime.atn.LexerATNSimulator.closure(LexerATNSimulator.java:478) at org.antlr.v4.runtime.atn中线程"main“java.lang.StackOverflowError中的异常.LexerATNSimulator.closure(LexerATNSimulator.java:478) at org.antlr.v4.runtime.atn.LexerATNSimulator.closure(LexerATNSimulator.java:458) at org.antlr.v4.runtime.atn.LexerATNSimulator.closure(LexerATNSimulator.java:478) at org.antlr.v4.runtime.atn.LexerATNSimulator.closure(LexerATNSimulator.java:478)

请提出什么是可能的根本原因。

**Lexer Grammar**

lexer grammar  ASPLexer;


HTML_COMMENT    
    : '<!--' .*? '-->'
    ;

HTML_CONDITIONAL_COMMENT    
    : '<![' .*? ']>'
    ;

XML_DECLARATION
    : '<?xml' .*? '>'
    ;

CDATA       
    : '<![CDATA[' .*? ']]>' 
    ;

DTD 
    : '<!' .*? '>'
    ;

SCRIPTLET 
    : '<?' .*? '?>'
    | '<%' .*? '%>'
    ;

SEA_WS
    :  (' '|'\t'|'\r'? '\n')+ 
    ;

SCRIPT_OPEN
    : '<script' .*? '>' ->pushMode(SCRIPT)
    ;

STYLE_OPEN
    : '<style' .*? '>'  ->pushMode(STYLE)
    ;

TAG_OPEN
    : '<' -> pushMode(TAG)
    ;

HTML_TEXT
    : ~'<'+
    ;   

//
// tag declarations
//
mode TAG;

TAG_CLOSE      
    : '>' -> popMode
    ;

TAG_SLASH_CLOSE     
    : '/>' -> popMode
    ;

TAG_SLASH      
    : '/' 
    ;

SCRIPT_TAG_OPEN
    : '<%' -> pushMode(SCRIPTVALUE)
    ;
//
// lexing mode for attribute values
//
TAG_EQUALS     
    : '=' -> pushMode(ATTVALUE)
    ;

TAG_NAME      
    : TAG_NameStartChar TAG_NameChar* 
    ;

TAG_WHITESPACE
    : [ \t\r\n] -> skip 
    ;

fragment
HEXDIGIT        
    : [a-fA-F0-9]
    ;

fragment
DIGIT           
    : [0-9]
    ;

fragment
TAG_NameChar        
    : TAG_NameStartChar
    | '-' 
    | '_' 
    | '.' 
    | DIGIT 
    |   '\u00B7'
    |   '\u0300'..'\u036F'
    |   '\u203F'..'\u2040'
    ;

fragment
TAG_NameStartChar
    :   [:a-zA-Z]
    |   '\u2070'..'\u218F' 
    |   '\u2C00'..'\u2FEF' 
    |   '\u3001'..'\uD7FF' 
    |   '\uF900'..'\uFDCF' 
    |   '\uFDF0'..'\uFFFD'
    ;

//
// <scripts>
//
mode SCRIPT;

SCRIPT_BODY
    : .*? '</script>' -> popMode
    ;

SCRIPT_SHORT_BODY
    : .*? '</>' -> popMode
    ;

//
// <styles>
//
mode STYLE;

STYLE_BODY
    : .*? '</style>' -> popMode
    ;

STYLE_SHORT_BODY
    : .*? '</>' -> popMode
    ;

//
// attribute values
//
mode ATTVALUE;

// an attribute value may have spaces b/t the '=' and the value
ATTVALUE_VALUE
    : [ ]* ATTRIBUTE -> popMode 
    ;

ATTRIBUTE
    : DOUBLE_QUOTE_STRING
    | SINGLE_QUOTE_STRING
    | ATTCHARS 
    | HEXCHARS
    | DECCHARS
    ;

fragment ATTCHAR
    : '-'
    | '_'
    | '.'
    | '/'
    | '+'
    | ','
    | '?'
    | '='
    | ':'
    | ';'
    | '#'
    | [0-9a-zA-Z]
    ;

fragment ATTCHARS
    : ATTCHAR+ ' '?
    ;

fragment HEXCHARS
    : '#' [0-9a-fA-F]+
    ;

fragment DECCHARS
    : [0-9]+ '%'?
    ;

fragment DOUBLE_QUOTE_STRING
    : '"' ~[<"]* '"'
    ;
fragment SINGLE_QUOTE_STRING
    : '\'' ~[<']* '\''
    ;

mode SCRIPTVALUE;

SCRIPT_TAG_VALUE
    : ATTCHARSCRIPTS*
    ;

SCRIPT_TAG_CLOSE
    : '%>' -> popMode
    ;

fragment ATTCHARSCRIPT
    : '-'
    | '_'
    | '.'
    | '/'
    | '+'
    | ','
    | '?'
    | '='
    | ':'
    | ';'
    | '#'
    | ')'
    | '('
    | '"'
    | '\r'
    | '\n'
    | ' '
    | [0-9a-zA-Z]
    ;

fragment ATTCHARSCRIPTS
    : ATTCHARSCRIPT* ' '?
    ;

**Parser Grammar**


parser grammar ASPParser;

options { tokenVocab=ASPLexer; }

htmlDocument    
    : (scriptlet | SEA_WS)* xml? (scriptlet | SEA_WS)* dtd? (scriptlet | SEA_WS)* htmlElements*
    ;

htmlElements
    : htmlMisc* htmlElement htmlMisc*
    ;

htmlElement     
    : TAG_OPEN htmlTagName htmlAttribute* scriptlettag* htmlAttribute* TAG_CLOSE htmlContent TAG_OPEN TAG_SLASH htmlTagName TAG_CLOSE
    | TAG_OPEN htmlTagName htmlAttribute* TAG_SLASH_CLOSE
    | TAG_OPEN htmlTagName htmlAttribute* TAG_CLOSE
    | scriptlet
    | script
    | style
    ;

htmlContent     
    : htmlChardata? ((htmlElement | xhtmlCDATA | htmlComment) htmlChardata?)*
    ;

htmlAttribute   
    : htmlAttributeName TAG_EQUALS htmlAttributeValue
    | htmlAttributeName
    | scriptlet
    ;

htmlAttributeName
    : TAG_NAME
    ;

htmlAttributeValue
    : ATTVALUE_VALUE
    ;

htmlTagName
    : TAG_NAME
    ;

htmlChardata    
    : HTML_TEXT 
    | SEA_WS
    ;

htmlMisc        
    : htmlComment 
    | SEA_WS
    ;

htmlComment
    : HTML_COMMENT
    | HTML_CONDITIONAL_COMMENT
    ;

xhtmlCDATA
    : CDATA
    ;

dtd
    : DTD
    ;

xml
    : XML_DECLARATION
    ;

scriptlet
    : SCRIPTLET
    ;

scriptlettag
    : SCRIPT_TAG_OPEN SCRIPT_TAG_VALUE SCRIPT_TAG_CLOSE
    ;

script
    : SCRIPT_OPEN ( SCRIPT_BODY | SCRIPT_SHORT_BODY)
    ;

style
    : STYLE_OPEN ( STYLE_BODY | STYLE_SHORT_BODY)
    ;

**Input File**

<!DOCTYPE html>
<html>
<%
dim cars
cars=Request.Form("cars")
%>
<body>
<form action="demo_radiob.asp" method="post">
<p>Please select your favorite car:</p>

<input type="radio" name="cars"
<% 
if cars="Volvo" then Response.Write("checked") 
%>
value="Volvo">Volvo</input>
<br>
<input type="radio" name="cars"
<% if cars="Saab" then Response.Write("checked") %>
value="Saab">Saab</input>
<br>
<input type="radio" name="cars"
<% if cars="BMW" then Response.Write("checked") %>
value="BMW">BMW</input>
<br><br>
<input type="submit" value="Submit" />
</form>
<%
if cars<>"" then
   Response.Write("<p>Your favorite car is: " & cars & "</p>")
end if
%>
</body>
</html>

Answer 1

这个bug最终是固定在ANTLR。现在，ANTLR在生成时而不是在运行时报告EPSILON_CLOSURE。