[antlr-interest] Reading a string of fixed size

[Alexandre Hamez]

Thanks for your interest. But the fact is that I want to create a  
Token with exactly NUMBER characters. The following characters will  
match for other token. It's not an error if there are characters  
which follow. Its mean that I can have something like that:

	CAMI_STRING (',' CAMI_STRING)*

( for newcomers: CAMI_STRING : NUMBER ':' STRING where the size of  
STRING is given by NUMBER).


Moreover, as a strange side effect of the following code, newlines  
make the parser completely mad:

> CAMI_STRING
> 	:
> 	NUMBER ':'
> 	{
> 		// Get the current position in stream
> 		int start  = input.getCharPositionInLine();
> 		// Computing the position of the last character of the STRING to  
> be read
> 		int end = start + Integer.parseInt($NUMBER.text) - 1;
> 		// Set the value of the returned value to STRING
> 		setText(input.substring(start,end));
> 		// Update the position in the stream
> 		input.seek(end+1);
> 	}
> 	;




On 27 août 07, at 12:24, Edwards, Waverly wrote:

> I gave it another chance, not knowing you could used rules as  
> variables.  Here is something a little more terse CAMI_STRING2  
> though I generate an error which I don't understand how to get rid  
> of.  It didn't happen in the CAMI_STRING version.
>
> The error:
> line 1:0 required (...)+ loop did not match anything at input  
> '5:abcde'
>
>
> W.
>
> grammar  TESTCAMISTRING;
>
> fragment
> Letter        :	'a'..'z' | 'A'..'Z' ;
> 	
> fragment	
> Digit	      :	'0'..'9' ;
>
> fragment
> AlphaNum      :	Letter | Digit ;
>
> fragment
> Number        : Digit+ ;
>
> fragment
> AlphaNumStr   : Letter AlphaNum* ;
>
>
> prog	      :	start+ ;
>
> start         : CAMI_STRING2
>               ;
> NEWLINE	:	('\r\n'|'\r'|'\n') ;
>
>
> // works just fine but is not as efficient or terse as CAMI_STRING2	
> CAMI_STRING   : Digit+ ':' Letter AlphaNum*
>     {
>         String wholeStr,numStr,fixLenStr;
>         int colonLoc, num;
>         boolean validate;
>
>         wholeStr  = getText().toString();
>         colonLoc  = wholeStr.indexOf(":");
>         numStr    = wholeStr.substring(0, colonLoc);
>         num       = Integer.parseInt(numStr);
>         fixLenStr = wholeStr.substring(colonLoc+1);
>         validate  = (num == fixLenStr.length() );
>         if ( validate == true )
>             System.out.println(numStr + "," + fixLenStr );
>         else
>             System.out.println("ERROR: num:Str length mismatch");
>     };
>
>
> CAMI_STRING2   : Number ':' AlphaNumStr
>     {
>         int num           = Integer.parseInt($Number.text);
>         String fixLenStr  = $AlphaNumStr.text;
>         boolean validate  = (num == fixLenStr.length() );
>         if ( validate == true )
>             System.out.println( num + "," + fixLenStr );
>         else
>             System.out.println("ERROR: num:Str length mismatch");
>     };
>
>
> -----Original Message-----
> From: antlr-interest-bounces at antlr.org [mailto:antlr-interest- 
> bounces at antlr.org] On Behalf Of Edwards, Waverly
> Sent: Monday, August 27, 2007 5:53 AM
> To: antlr-interest at antlr.org
> Subject: Re: [antlr-interest] Reading a string of fixed size
>
>
> Here is something that is functional.
>
> I'm a newbie at all of this, ANTLR and Regular expressions so don't  
> take this as the Gospel.  You'll want to check this out carefully.
>
> I didn't even know you could do this:  Integer.parseInt($NUMBER.text)
>
> If you can, this code could be shorter and I will have learned  
> something else useful.
>
>
> W.
>
>
>
> grammar  TESTCAMISTRING;
>
> fragment
> Letter        :	'a'..'z' | 'A'..'Z' ;
> 	
> fragment	
> Digit	      :	'0'..'9' ;
>
> fragment
> AlphaNum      :	Letter | Digit ;
>
> prog	      :	start+ ;
>
> start         : CAMI_STRING
>               ;
> NEWLINE	:	('\r\n'|'\r'|'\n') ;
>
> 	
> CAMI_STRING   : Digit+ ':' Letter AlphaNum*
>     {
>         String wholeStr,numStr,fixLenStr;
>         int colonLoc, num;
>         boolean validate;
>
>         wholeStr  = getText().toString();
>         colonLoc  = wholeStr.indexOf(":");
>         numStr    = wholeStr.substring(0, colonLoc);
>         num       = Integer.parseInt(numStr);
>         fixLenStr = wholeStr.substring(colonLoc+1);
>         validate  = (num == fixLenStr.length() );
>         if ( validate == true )
>             System.out.println(numStr + "," + fixLenStr);
>         else
>             System.out.println("ERROR: num:Str length mismatch");
>     };
>
>
> -----Original Message-----
> From: antlr-interest-bounces at antlr.org [mailto:antlr-interest- 
> bounces at antlr.org] On Behalf Of Alexandre Hamez
> Sent: Monday, August 27, 2007 3:33 AM
> To: antlr-interest at antlr.org
> Subject: [antlr-interest] Reading a string of fixed size
>
> Hi everybody,
>
> 	I need to read a string of a fixed size. For example : '5:abcde'.
> The size of the string to be read is given by the number before the  
> ':'. So I've written the following:
>
> CAMI_STRING
> 	:
> 	NUMBER ':'
> 	{
> 		// Get the current position in stream
> 		int start  = input.getCharPositionInLine();
> 		// Computing the position of the last character of the STRING to  
> be read
> 		int end = start + Integer.parseInt($NUMBER.text) - 1;
> 		// Set the value of the returned value to STRING
> 		setText(input.substring(start,end));
> 		// Update the position in the stream
> 		input.seek(end+1);
> 	}
> 	;
> 	
> NUMBER	
> 	: 	
> 	'0'..'9'+
> 	;
>
>
> It works quite well until the string to be read contains a number  
> itself. Have you an idea on this problem? Thanks for you help!
>
>
> ---------------------------------------------------------------------- 
> --
> ---
> Alexandre Hamez   LIP6 - MoVe / EPITA - LRDE
> LIP6: tel: +33 1 44 27 31 92  / Bureau 818
> 104 Avenue du Président Kennedy 75016 Paris http://www-src.lip6.fr/ 
> ~Alexandre.Hamez
>
>
>

------------------------------------------------------------------------ 
---
Alexandre Hamez   LIP6 - MoVe / EPITA - LRDE
LIP6: tel: +33 1 44 27 31 92  / Bureau 818
104 Avenue du Président Kennedy 75016 Paris
http://www-src.lip6.fr/~Alexandre.Hamez


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