Date:         Thu, 22 Apr 2004 20:25:59 -0400
Reply-To:     SAS Bigot <sas_bigot@ML1.NET>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         SAS Bigot <sas_bigot@ML1.NET>
Subject:      Re: Searching backward through a file.
In-Reply-To:  <446DDE75CFC7E1438061462F85557B0F01DFA647@remail2.westat.com>
Content-Type: text/plain; charset="US-ASCII"

You need to be careful, especially in macros.


----- Original message -----
From: "Ed Heaton" <EdHeaton@WESTAT.COM>
To: SAS-L@LISTSERV.UGA.EDU
Date: Thu, 22 Apr 2004 12:57:03 -0400
Subject: Re: Searching backward through a file.

Paul,

Eureka!  You have hit on the technique.  Thanks a million.  (Of course
it's
not foolproof.)  I will post my code when I get it developed.  I have a
meeting to attend right now.

Ed

-----Original Message-----
From: Choate, Paul@DDS [mailto:pchoate@DDS.CA.GOV]
Sent: Thursday, April 22, 2004 12:47 PM
To: Ed Heaton; SAS-L@LISTSERV.UGA.EDU
Subject: RE: Searching backward through a file.



This is off your question Ed, but why not count parentheses between ";"
delimiters and keep the line numbers of the ";" and the prior ";" that
bracket the unbalanced count?

Paul Choate
DDS Data Extraction
(916) 654-2160

-----Original Message-----
From: Ed Heaton [mailto:EdHeaton@WESTAT.COM <mailto:EdHeaton@WESTAT.COM>
]
Sent: Thursday, April 22, 2004 8:41 AM
To: SAS-L@LISTSERV.UGA.EDU
Subject: Searching backward through a file.

Good morning, all;

I am trying to create a little job to search SAS code for unbalanced
parentheses.  The following will alert me if I have an extra right
parenthesis.

Data _null_ ;
    InFile sasCode end=eof ;
    Input ;
    If not missing(_inFile_) then do i=1 to length(_inFile_) ;
        Select ( rank( subStr( _inFile_ , i , 1 ) ) ) ;
            When (40)  leftParen + 1 ;
            When (41) rightParen + 1 ;
            Otherwise ;
        End ;
        If ( leftParen lt rightParen ) then put _all_ ;
    End ;
    If eof then call symPut( "n" , put( _n_ , best. ) ) ;
Run ;

Now I want to search for an extra left parenthesis.  I envision starting
at
the bottom of the file and searching backward.  Something like...

Data _null_ ;
    Retain N &n ;
    InFile sasCode ;
    /* Go to the bottom of the file. */
    Input #N ;
    N + -1 ;
    If not missing(_inFile_) then do i=length(_inFile_) to 1 by -1 ;
        Select ( rank( subStr( _inFile_ , i , 1 ) ) ) ;
            When (40)  leftParen + 1 ;
            When (41) rightParen + 1 ;
            Otherwise ;
        End ;
        If ( leftParen gt rightParen ) then put _all_ ;
    End ;
    If ( _n_ eq &n ) then stop ;
Run ;

Of course, this doesn't work.  Is there a way to make SAS read backward
through a file.  My other option is to write each line from the first
read
into a data set, reverse the order of the data set, and use it in the
second

DATA step.  This seems very clunky to me.  Any suggestions?

Ed

Edward Heaton, SAS Senior Systems Analyst,
Westat (An Employee-Owned Research Corporation),
1600 Research Boulevard, RW-3541, Rockville, MD 20850-3195
Voice: (301) 610-4818                  Fax: (301) 610-5128
mailto:EdHeaton@Westat.com <mailto:EdHeaton@Westat.com>
http://www.Westat.com <http://www.Westat.com>

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