[jboss-jira] [JBoss JIRA] Closed: (JBRULES-855) Jboss regex does not support all escape sequence

[Edson Tirelli (JIRA)]

     [ http://jira.jboss.com/jira/browse/JBRULES-855?page=all ]

Edson Tirelli closed JBRULES-855.
---------------------------------

    Resolution: Done

Support to escapes added to the grammar. 

I hope I did not forgot anyone... :)

STRING
    :  ('"' ( EscapeSequence | ~('\\'|'"') )* '"')
     | ('\'' ( EscapeSequence | ~('\\'|'\'') )* '\'')
    ;

fragment
HexDigit : ('0'..'9'|'a'..'f'|'A'..'F') ;

fragment
EscapeSequence
    :   '\\' ('b'|'B'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\'|'.'|'o'|
              'x'|'a'|'e'|'c'|'d'|'D'|'s'|'S'|'w'|'W'|'p'|'A'|
              'G'|'Z'|'z'|'Q'|'E'|'*'|'['|']'|'('|')'|'$'|'^'|
              '{'|'}'|'?'|'+'|'-'|'&'|'|')
    |   UnicodeEscape
    |   OctalEscape
    ;

fragment
OctalEscape
    :   '\\' ('0'..'3') ('0'..'7') ('0'..'7')
    |   '\\' ('0'..'7') ('0'..'7')
    |   '\\' ('0'..'7')
    ;

fragment
UnicodeEscape
    :   '\\' 'u' HexDigit HexDigit HexDigit HexDigit
    ;


> Jboss regex does not support all escape sequence
> ------------------------------------------------
>
>                 Key: JBRULES-855
>                 URL: http://jira.jboss.com/jira/browse/JBRULES-855
>             Project: JBoss Rules
>          Issue Type: Bug
>      Security Level: Public(Everyone can see) 
>    Affects Versions: 4.0.0.MR2
>         Environment: Windows XP
>            Reporter: Krishnan Sivaramakrishna Iyer
>         Assigned To: Edson Tirelli
>             Fix For:  4.0.0.MR3
>
>
> Currently, if there exists a string such as 
> final String version = "version 12.2";
> and you try to match it against the following regex 
> version\\s*\\d+\\.\\d+.*
> It will not match. This is because of the following problem 
> <tirelli> newbie: found the problem
> <tirelli> it is a bug
> <tirelli> but there is a workaround
> <tirelli> problem is the current DRL grammar does not allow to escape things like \s and \d
> <tirelli> EscapeSequence
> <tirelli>     :   '\\' ('b'|'t'|'n'|'f'|'r'|'\"'|'\''|'\\'|'.')
> <tirelli> those are the only accepted symbols to be escaped today
> <tirelli> may I ask you plz to open a JIRA requesting support to all regexp symbols? I will fix that for 4.0 final
> <tirelli> meanwhile, you can do this to work:
> <tirelli> line matches "version[ \t]*[0-9]+\.[0-9]+.*"
> Thanks, 
> Krishnan
> Test case : 
> #created on: May 16, 2007
> package com.sample
>  
> #list any import classes here.
> import com.sample.Device;
> import com.sample.Line;
>  
> #declare any global variables here
>  
> rule "Check for Cisco Version Exp"
>  
> 	when
> 		Line ( line matches "version\\s*\\d+\\.\\d+\\.*" )
> 	then 
> 		System.out.println("There exists a line that matches cisco version expression.");
> end
>  
> ====
> package com.sample;
>  
> import java.lang.String;
>  
> /**
>  * @author kiyer
>  *
>  */
> public class Line {
>  
> 	private String line;
>  
> 	public Line(String line) {
> 		setLine(line);
> 	}
>  
> 	/**
> 	 * @return the line
> 	 */
> 	public String getLine() {
> 		return line;
> 	}
>  
> 	/**
> 	 * @param line the line to set
> 	 */
> 	public void setLine(String line) {
> 		this.line = line;
> 	}
>  
> }
> ===
>  
> package com.sample;
>  
> import java.io.BufferedReader;
> import java.io.FileReader;
> import java.io.InputStreamReader;
> import java.io.Reader;
>  
> import org.drools.RuleBase;
> import org.drools.RuleBaseFactory;
> import org.drools.compiler.PackageBuilder;
> import org.drools.StatefulSession;
> import org.drools.rule.Package;
>  
> /**
>  * This is a sample file to launch a rule package from a rule source file.
>  */
> public class CfiTest {
>  
> 	public static final void main(String[] args) {
>         try {
>  
>             //load up the rulebase
>             final RuleBase ruleBase = readRule();
>             final StatefulSession session = ruleBase.newStatefulSession();
>  
>             Line lineObj = new Line("version 12.2");
>             session.assertObject(lineObj);            
>             session.fireAllRules();
>             session.dispose();
>         } catch (Throwable t) {
>             t.printStackTrace();
>         }
>     }
>  
>     /**
>      * Please note that this is the "low level" rule assembly API.
>      */
>     private static RuleBase readRule() throws Exception {
>         //read in the source
>         final Reader source = new InputStreamReader( DroolsTest.class.getResourceAsStream( "/CfiTest.drl" ) );
>  
>         //optionally read in the DSL (if you are using it).
>         //Reader dsl = new InputStreamReader( DroolsTest.class.getResourceAsStream( "/mylang.dsl" ) );
>  
>         //Use package builder to build up a rule package.
>         //An alternative lower level class called "DrlParser" can also be used...
>  
>         final PackageBuilder builder = new PackageBuilder();
>  
>         //this wil parse and compile in one step
>         //NOTE: There are 2 methods here, the one argument one is for normal DRL.
>         builder.addPackageFromDrl( source );
>  
>         //Use the following instead of above if you are using a DSL:
>         //builder.addPackageFromDrl( source, dsl );
>  
>         //get the compiled package (which is serializable)
>         final Package pkg = builder.getPackage();
>  
>         //add the package to a rulebase (deploy the rule package).
>         final RuleBase ruleBase = RuleBaseFactory.newRuleBase();
>         ruleBase.addPackage( pkg );
>         System.out.println("Successfully loaded the rules file.");
>         return ruleBase;
>     }
>  
> }

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