使用antlr解析特定函数中的lua IF语句

Question

我使用 Lua.g 语法和 java 中的 antlr 生成了一个 Lua Parser。

我想要解析的 lua 代码基本上是这样的

function uniqueid_some_event (e) 
 if (e:HasString("string1")) then  
   -- do something
 end
 if (e:HasString("string2")) then  
  -- do something
 end
end

对于特定的参与者绑定，我在不同的文件中有数百个这样的事件。

现在我想解析这些文件并收集每个检查的条件 - 在上述情况下 - 我想提取“string1”和“string2”作为事件触发器。 （更准确地说，我想创建一个只显示每个文件的触发器的报告）

我认为我需要以某种方式修改 Lua.g 以在其中添加我自己的逻辑，但我迷路了，因为我没有找到任何关于此的文档 - 我查看了 LuaEclise，它基本上做了一些事情，但它也不适用于我.

那么 - 是否可以在生成的 LuaParser 中添加某种 w3c DOM 返回值？或者像 getFunctions() 这样返回所有找到的函数，在每个函数中 getHasStringStatements() 会返回条件？

Answer 1

我不建议使用 ANTLR wiki 中的 Lua 语法。 AFAIK，它有很多问题（没有正确的长字符串和长 cmets、无效的数字/十六进制标记、全局回溯等等）。

这是 Lua 5.2 的 (IMO) 更好的语法：

/*
Copyright (c) 2011-2012 by Bart Kiers

Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
*/
grammar Lua52;

options {
 output=AST;
 ASTLabelType=CommonTree;
}

tokens {
  // literals
  And       = 'and';
  Break     = 'break';
  Do        = 'do';
  Else      = 'else';
  Elseif    = 'elseif';
  End       = 'end';
  False     = 'false';
  For       = 'for';
  Function  = 'function';
  Goto      = 'goto';
  If        = 'if';
  In        = 'in';
  Local     = 'local';
  Nil       = 'nil';
  Not       = 'not';
  Or        = 'or';
  Repeat    = 'repeat';
  Return    = 'return';
  Then      = 'then';
  True      = 'true';
  Until     = 'until';
  While     = 'while';
  Add       = '+';
  Minus     = '-';
  Mult      = '*';
  Div       = '/';
  Mod       = '%';
  Pow       = '^';
  Length    = '#';
  Eq        = '==';
  NEq       = '~=';
  LTEq      = '<=';
  GTEq      = '>=';
  LT        = '<';
  GT        = '>';
  Assign    = '=';
  OPar      = '(';
  CPar      = ')';
  OBrace    = '{';
  CBrace    = '}';
  OBrack    = '[';
  CBrack    = ']';
  ColCol    = '::';
  SCol      = ';';
  Col       = ':';
  Comma     = ',';
  DotDotDot = '...';
  DotDot    = '..';
  Dot       = '.';

  // imaginary tokens
  ASSIGNMENT;
  LOCAL_ASSIGNMENT;
  CONDITION;
  UNARY_MINUS;
  CALL;
  COL_CALL;
  INDEX;
  EXPR_LIST;
  VAR_LIST;
  CHUNK;
  NAME_LIST;
  LABEL;
  TABLE;
  FIELD_LIST;
  FIELD;
  FOR_IN;
  PARAM_LIST;
  FUNCTION;
  ASSIGNMENT_VAR;
  VAR;
}

@parser::header {
  package luja.parser;
}

@lexer::header {
  package luja.parser;
  import java.math.*;
}

@parser::members {

  private boolean addSelf = false;

  private CommonTree createPowAST(List tokens) {
    int n = tokens.size();

    CommonTree ast = new CommonTree(new CommonToken(Pow, "^"));
    ast.addChild((CommonTree)tokens.get(n - 2));
    ast.addChild((CommonTree)tokens.get(n - 1));

    for(int i = n - 3; i >= 0; i--) {
      CommonTree temp = new CommonTree(new CommonToken(Pow, "^"));
      temp.addChild((CommonTree)tokens.get(i));
      temp.addChild(ast);
      ast = temp;
    }

    return ast;
  }

  private CommonTree namesToVar(List<String> names, String name) {
    names.add(name);
    return namesToVar(names);
  }

  private CommonTree namesToVar(List<String> names) {

    if(names.size() == 1) {
      return new CommonTree(new CommonToken(Name, names.get(0)));
    }

    CommonTree ast = new CommonTree(new CommonToken(VAR, "VAR"));

    ast.addChild(new CommonTree(new CommonToken(Name, names.get(0))));

    for(int i = 1; i < names.size(); i++) {
      CommonTree indexNode = new CommonTree(new CommonToken(INDEX, "INDEX"));
      indexNode.addChild(new CommonTree(new CommonToken(Name, names.get(i))));
      ast.addChild(indexNode);
    }

    return ast;
  }

  @Override
  public void reportError(RecognitionException e) {
    throw new RuntimeException(e); 
  }
}

@lexer::members {

  private boolean ahead(CharSequence chars) {
    for(int i = 0; i < chars.length(); i++) {
      if(input.LA(i + 1) != chars.charAt(i)) {        
        return false;
      }
    }
    return true;
  }

  @Override
  public void reportError(RecognitionException e) {
    throw new RuntimeException(e); 
  }

  private String unescape(String text) {
    StringBuilder b = new StringBuilder();
    String regex = "\\\\([\\\\abfnrtv\"']|\r?\n|\r|\\d{1,3}|x[0-9a-fA-F]{2}|z\\s*)|(?s).";
    java.util.regex.Matcher m = java.util.regex.Pattern.compile(regex).matcher(text);
    while(m.find()) {
      if(m.group(1) != null) {
        // an escaped char
        String matched = m.group(1);
        if(matched.equals("\\")) b.append("\\");
        else if(matched.equals("a")) b.append("\u0007");
        else if(matched.equals("b")) b.append("\u0008");
        else if(matched.equals("f")) b.append("\u000C");
        else if(matched.equals("n")) b.append("\n");
        else if(matched.equals("r")) b.append("\r");
        else if(matched.equals("t")) b.append("\t");
        else if(matched.equals("v")) b.append("\u000B");
        else if(matched.equals("\"")) b.append("\"");
        else if(matched.equals("'")) b.append("'");
        else if(matched.matches("\r?\n|\r")) b.append(matched);
        else if(matched.matches("\\d{1,3}")) b.append((char)Integer.parseInt(matched));
        else if(matched.matches("x[0-9a-fA-F]{2}")) b.append((char)Integer.parseInt(matched.substring(1), 16));
        else if(matched.equals("z\\s*")) { /* do nothing, remove from string */ }
      }
      else {
        // a normal char, append "as is"
        b.append(m.group());
      }
    }
    return b.toString();
  }
}

//////////////////////////////// parser rules //////////////////////////////// 
parse
 : chunk EOF -> chunk
 ;

chunk
 : stat* ret_stat? -> ^(CHUNK stat* ret_stat?)
 ;

stat
 : (assignment)=> assignment
 | var[false]                         // must be a function call, not an index: check and throw exception
 | do_block 
 | while_stat
 | repeat_stat
 | local
 | goto_stat
 | if_stat
 | for_stat
 | function
 | label
 | Break
 | ';' -> /* remove from AST (empty rewrite rule) */
 ;

do_block
 : Do chunk End -> ^(Do chunk)
 ;

while_stat
 : While expr do_block -> ^(While expr do_block)
 ;

repeat_stat
 : Repeat chunk Until expr -> ^(Repeat chunk expr) 
 ;

assignment
 : var_list '=' expr_list // in every 'var' in 'var_list', the last must be an 'index', not a 'call'
   -> ^(ASSIGNMENT ^(VAR_LIST var_list) ^(EXPR_LIST expr_list))
 ;

local
 : Local ( name_list '=' expr_list -> ^(LOCAL_ASSIGNMENT ^(NAME_LIST name_list) ^(EXPR_LIST expr_list))
         | Function Name func_body -> ^(LOCAL_ASSIGNMENT ^(NAME_LIST Name) ^(EXPR_LIST func_body))
         )
 ;

goto_stat
 : Goto Name -> ^(Goto Name)
 ;

if_stat
 : If expr Then chunk elseif_stat* else_stat? End -> ^(If ^(CONDITION expr chunk) elseif_stat* else_stat?)
 ;

elseif_stat
 : Elseif expr Then chunk -> ^(CONDITION expr chunk)
 ;

else_stat
 : Else chunk -> ^(CONDITION True chunk)
 ;

for_stat
 : For ( Name '=' a=expr ',' b=expr (',' c=expr)? do_block -> ^(For Name $a $b $c? do_block)
       | name_list In expr_list do_block                   -> ^(FOR_IN ^(NAME_LIST name_list) ^(EXPR_LIST expr_list) do_block)
       )
 ;

function
 : Function names ( Col Name {addSelf=true;} func_body {addSelf=false;} 
                    -> ^(ASSIGNMENT ^(VAR_LIST {namesToVar($names.list, $Name.text)}) ^(EXPR_LIST func_body))
                  | func_body
                    -> ^(ASSIGNMENT ^(VAR_LIST {namesToVar($names.list)}) ^(EXPR_LIST func_body))
                  )
 ;

names returns [List<String> list]
@init{$list = new ArrayList<String>();}
 : a=Name {$list.add($a.text);} ('.' b=Name {$list.add($b.text);})*
 ;

function_literal
 : Function func_body -> func_body
 ;

func_body
 : '(' param_list ')' chunk End -> ^(FUNCTION param_list chunk)
 ;

param_list
 : name_list (',' DotDotDot)? -> ^(PARAM_LIST name_list DotDotDot?)
 | DotDotDot?                 -> ^(PARAM_LIST DotDotDot?)
 ;

ret_stat
 : Return expr_list? ';'? -> ^(Return expr_list?)
 ;

expr
 : or_expr
 ;

or_expr
 : and_expr (Or^ and_expr)*
 ;

and_expr
 : rel_expr (And^ rel_expr)*
 ;

rel_expr
 : concat_expr ((LT | GT | LTEq | GTEq | NEq | Eq)^ concat_expr)?
 ;

concat_expr
 : add_expr (DotDot^ add_expr)*
 ;

add_expr
 : mult_expr ((Add | Minus)^ mult_expr)*
 ;

mult_expr
 : unary_expr ((Mult | Div | Mod)^ unary_expr)*
 ;

unary_expr
 : Minus unary_expr -> ^(UNARY_MINUS unary_expr)
 | Length pow_expr  -> ^(Length pow_expr)
 | Not unary_expr   -> ^(Not unary_expr)
 | pow_expr
 ;

// right associative
pow_expr
// : (a=atom -> $a) ((Pow atom)+ -> ^(Pow atom+))?
 : (a+=atom -> $a) ((Pow a+=atom)+ -> {createPowAST($a)})?
 ;

atom
 : var[false]
 | function_literal
 | table_constructor
 | DotDotDot 
 | Number
 | String
 | Nil
 | True
 | False
 ;

var[boolean assign]
 : (callee[assign] -> callee) ( (tail)=> (((tail)=> t=tail)+ -> {assign}? ^(ASSIGNMENT_VAR callee tail+)
                                                             ->           ^(VAR callee tail+))
                              )?
 ;

callee[boolean assign]
 : '(' expr ')' -> expr
 | Name
 ;

tail
 : '.' Name                    -> ^(INDEX String[$Name.text])
 | '[' expr ']'                -> ^(INDEX expr)
 | ':' Name '(' expr_list? ')' -> ^(INDEX {new CommonTree(new CommonToken(String, $Name.text))}) ^(COL_CALL expr_list?)
 | ':' Name table_constructor  -> ^(INDEX {new CommonTree(new CommonToken(String, $Name.text))}) ^(COL_CALL table_constructor)
 | ':' Name String             -> ^(INDEX {new CommonTree(new CommonToken(String, $Name.text))}) ^(COL_CALL String)
 | '(' expr_list? ')'          -> ^(CALL expr_list?)
 | table_constructor           -> ^(CALL table_constructor)
 | String                      -> ^(CALL String)
 ;

table_constructor
 : '{' field_list? '}' -> ^(TABLE field_list?)
 ;

field_list
 : field (field_sep field)* field_sep? -> field+
 ;

field
 : '[' expr ']' '=' expr -> ^(FIELD expr expr)
 | Name '=' expr         -> ^(FIELD {new CommonTree(new CommonToken(String, $Name.text))} expr)
 | expr                  -> ^(FIELD expr)
 ;

field_sep
 : ',' 
 | ';'
 ;

label
 : '::' Name '::' -> ^(LABEL Name)
 ;

var_list
 : var[true] (',' var[true])* -> var+
 ;

expr_list
 : expr (',' expr)* -> expr+
 ;

name_list
 : Name (',' Name)* -> {addSelf}? {new CommonTree(new CommonToken(Name, "self"))} Name+
                    ->            Name+
 ;

//////////////////////////////// lexer rules //////////////////////////////// 
Name
 : (Letter | '_') (Letter | '_' | Digit)*
 ;

Number
 : (Digit+ ('.' Digit*)? Exponent? | '.' Digit+ Exponent?)    {setText(new java.math.BigDecimal($text).toPlainString().replaceAll("\\.0*$", ""));}
 | '0' ('x' | 'X') a=HexDigits ('.' b=HexDigits?)? c=BinaryExponent? 
   {
     double num = Long.parseLong($a.text, 16);

     if($b != null) {
       double fraction = Long.parseLong($b.text, 16) / Math.pow(16, $b.text.length());
       num += fraction;
     }

     if($c != null) {
       int binExp = Integer.valueOf($c.text.contains("+") ? $c.text.substring(2) : $c.text.substring(1));
       for(int i = 0; i < Math.abs(binExp); i++) {
         num = binExp < 0 ? num/2 : num*2;
       }
     }

     setText(new BigDecimal(Double.toString(num)).toPlainString().replaceAll("\\.0*$", ""));
   }
 ;

String
 : '"'  (EscapeSequence | ~('\\' | '"'  | '\r' | '\n'))* '"'  {setText(unescape($text.substring(1, $text.length()-1)));}
 | '\'' (EscapeSequence | ~('\\' | '\'' | '\r' | '\n'))* '\'' {setText(unescape($text.substring(1, $text.length()-1)));}
 | LongBracket                                                {setText($text.replaceAll("^\\[=*\\[|]=*]$", ""));}
 ;

//////////////////////////////// lexer rules to skip //////////////////////////////// 
Comment
 : '--' ( LongBracket
        | '[' '='* ~('=' | '[') ~('\r' | '\n')* // matches '--[=====...' as a single line comment
        | (~'[' ~('\r' | '\n')*)?
        )
        {skip();}
 ;

Space
 : (' ' | '\t' | '\r' | '\n' | '\u000C')+ {skip();}
 ;

//////////////////////////////// fragment lexer rules //////////////////////////////// 
fragment Letter
 : 'a'..'z' 
 | 'A'..'Z'
 ;

fragment Digit
 : '0'..'9'
 ;

fragment HexDigit
 : Digit
 | 'a'..'f'
 | 'A'..'F'
 ;

fragment HexDigits
 : HexDigit+
 ;

fragment Exponent
 : ('e' | 'E') ('-' | '+')? Digit+
 ;

fragment BinaryExponent
 : ('p' | 'P') ('-' | '+')? Digit+
 ;

fragment EscapeSequence
 : '\\' ( ('a' | 'b' | 'f' | 'n' | 'r' | 't' | 'v' | '\\' | '"' | '\'' | 'z' | LineBreak)
        | Digit (Digit Digit?)?
        | 'x' HexDigit HexDigit
        )
 ;

fragment LineBreak
 : '\r'? '\n'
 | '\r' 
 ;

fragment LongBracket
@init{StringBuilder b = new StringBuilder("]");}
 :
   // match opening bracket and build equal sized closing bracket
   '[' ('=' {b.append("=");})* '[' {b.append("]");}

   // keep matching chars until the closing bracket is ahead
   ({!ahead(b)}?=> (~'\\' | EscapeSequence) )*

   {
     if(input.LA(1) == EOF) {
       throw new RuntimeException("unfinished long comment or string near '<eof>'");
     }

     // let the lexer match the closing bracket
     match(b.toString());
   }

 ; 

//////////////////////////////// a fall through rule throwing an exception //////////////////////////////// 
Any
@after {throw new RuntimeException("unexpected symbol near: '" + $text + "'");}
 : .
 ;

如果您现在解析以下输入：

--[===[
    function uniqueid_some_event (e)
     if (e:HasString("ignore string1")) then
       -- do something
     end
     if (e:HasString("ignore string2")) then
      -- do something
     end
    end
    some invalid closing comment tags: ]==] ]====]
]===]

function uniqueid_some_event (e)
 if (e:HasString("string1")) then
   -- do something
 end
 if (e:HasString("string2")) then
  -- do something
 end
end

if (e:HasString("outside function...")) then end

您将获得从生成的解析器返回的以下 AST：

现在你需要做的就是遍历 AST，当你偶然发现 ASSIGNMENT 节点时，检查右子节点是否是一个包含 FUNCTION 的表达式列表。如果发生这种情况，请遍历此节点以查找其中包含字符串表达式的 if 语句。

这是一个开始：

public class LUjATest {

    private static void findFunctions(CommonTree tree) {
        if (tree == null) return;

        if(tree.getType() == Lua52Parser.ASSIGNMENT) {

            String name = tree.getChild(0).getChild(0).getText();
            CommonTree expressions = (CommonTree) tree.getChild(1);

            if(expressions.getChildCount() > 0 &&
                    expressions.getChild(0).getType() == Lua52Parser.FUNCTION) {

                System.out.println("walk the tree:\n  " + expressions.toStringTree() +
                        "\nto find all strings for event: '" + name + "'");
            }
        }
        else {
            for (int i = 0; i < tree.getChildCount(); i++) {
                findFunctions((CommonTree) tree.getChild(i));
            }
        }
    }

    public static void main(String[] args) throws Exception {
        Lua52Lexer lexer = new Lua52Lexer(new ANTLRFileStream("src/lua/test.lua"));
        Lua52Parser parser = new Lua52Parser(new CommonTokenStream(lexer));
        CommonTree tree = (CommonTree) parser.parse().getTree();
        findFunctions(tree);
    }
}

运行上面的类时，你会看到如下输出：

走树：
  (EXPR_LIST (FUNCTION (PARAM_LIST e) (CHUNK (if (CONDITION (VAR e (INDEX HasString) (COL_CALL string1)) CHUNK))) (if (CONDITION (VAR e (INDEX HasString) (COL_CALL string2)) CHUNK)))) )
查找事件的所有字符串：'uniqueid_some_event'