Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

I have a file; 
ADD TABLE "Benefits"
  AREA "Employee"
  DESCRIPTION "The benefits table contains employee benefits."
  DUMP-NAME "benefits"

ADD FIELD "EmpNum" OF "Benefits" AS integer
  FORMAT "zzzzzzzzz9"
  INITIAL "0"
  LABEL "Emp No"
  POSITION 2
  MAX-WIDTH 4
  VALEXP "CAN-FIND(employee OF benefits)"
  VALMSG "Employee must exist."
  HELP "Please enter the Emp Number"
  ORDER 10

ADD FIELD "HealthCare" OF "Benefits" AS character
  FORMAT "x(8)"
  INITIAL ""
  LABEL "Health Care"
  POSITION 3
  MAX-WIDTH 16
  HELP "Please enter the Health Care field."

[download]
In my script when i find a field i want to pick up the line below it to grab the format info; 
while (<INFILE1>){

#    define variables

    $FULL_LINE = $_;
    $TABDISPLAY = 0;
    $FIELDDISPLAY = 0;
    $DATEFIELD = 0;
    $SHORTLINE = substr($FULL_LINE,0,length($FULL_LINE)-2);
    @LINEARRAY[0..9] = split(/"+/, $SHORTLINE);
    $FIELDLENGTH = "";
    $FIELD = "";
    $TYPE = "";
    
#    decide if input line is table name or field name

    if($LINEARRAY[0]=/ADD TABLE/) {
        $TABLE="$LINEARRAY[1]";
        $TABDISPLAY=1;
print OUTFILE3  ("table=" . "$TABLE \n");
    } elsif    ($LINEARRAY[0]=/ADD FIELD/) {
        $FIELD=$LINEARRAY[1];
        $TYPE=$LINEARRAY[4];
        $FIELDDISPLAY=1;
        #need bit in here to pick up next line to set fieldlength belo
+w!
        $FIELDLENGTH=$LINEARRAY[1];
print OUTFILE3  ("field=" . "$FIELD \n");
print OUTFILE3  ("type=" . "$TYPE \n");
print OUTFILE3  ("length=" . "$FIELDLENGTH \n");
    };
#snipped the rest

[download]
OUTFILE3 currently looks like; 
table=Benefits
field=EmpNum
type= AS integer
length=EmpNum
field=HealthCare
type= AS character
length=HealthCare
fieldlength=HealthCare
srclength=varcharealthCar
field=LifeInsurance
type= AS integer
length=LifeInsurance

[download]
Anybody help?? Thanks

Replies are listed 'Best First'.
Re: How to skip a line?
by ikegami (Patriarch) on Jun 04, 2008 at 09:49 UTC
    You should find paragraph mode ($/ = '';) very useful. 
    local $/ = '';

while (<$fh>) {
   if (
      my ($table) = 
         /^ADD TABLE "([^"]+)"/
   ) {
      ...   
   }

   elsif (
      my ($field, $table, $type) =
         /^ADD FIELD "([^"]+)" OF "([^"]+)" AS (\w+)/
   ) {
      my ($format) = /^   FORMAT "([^"]+)"/m;
      ...
   }
}

    [download]

    And note the 'm' modifier on the regexp to change the meaning of '^'.

[reply]
[d/l]
[select]
      Thanks for your help - still not working though! Best to assume ive made a schoolboy error somewhere. Heres my current code. OUTFILE3 is now blank. 
      local $/ = '';

#    run script

while (<$INFILE1>){

#    define variables

    $FULL_LINE = $_;
    $TABDISPLAY = 0;
    $FIELDDISPLAY = 0;
    $DATEFIELD = 0;
    $SHORTLINE = substr($FULL_LINE,0,length($FULL_LINE)-2);
    @LINEARRAY[0..9] = split(/"+/, $SHORTLINE);

#    decide if input line is table name or field name

if (
      my ($table) = 
         /^ADD TABLE "([^"]+)"/
   ) {
    $TABDISPLAY=1;
print OUTFILE3  ("table=" . "$table \n");
   }

   elsif (
      my ($field, $table, $type) =
         /^ADD FIELD "([^"]+)" OF "([^"]+)" AS (\w+)/
   ) {
      my ($format) = /^   FORMAT "([^"]+)"/m;
        $FIELDDISPLAY=1;
        my ($format)=$FIELDLENGTH;
print OUTFILE3  ("field=" . "$field \n");
print OUTFILE3  ("type=" . "$type \n");
print OUTFILE3  ("length=" . "$FIELDLENGTH \n");
   }

      [download]
[reply]
[d/l]
        First and most important hint: Call perl with the -w parameter. On Unix you just have a first line "#!/usr/bin/perl -w" which does that automatically, with ActiveState Perl or whatever you are using on windows you might have to use perl /w <scriptname> on the command shell, I don't know how it works there.

        This will tell you that you have defined $table and $format twice (with my). Not a problem and not an error, but it leads to errors later when you want to use the first $format value and get only the second $format.

        It will also tell you that $FIELDLENGTH is undefined. The error message is "Use of uninitialized value in concatenation (.) or string at ./t4.pl line XX" with XX the line in which you print $FIELDLENGTH. So you never put anything into that variable

        Another hint: chomp() can be used to delete CR/LF line endings from a string. Much easier than substr(...) and works on unix too (where there is only one character, CR, as a line ending).

[reply]

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