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Re: Question about Open and Close

by graff (Chancellor)
on Jun 09, 2002 at 03:06 UTC ( [id://172871]=note: print w/replies, xml ) Need Help??


in reply to Question about Open and Close

A few comments, which I hope will be helpful:
  • When you have multiple output files open at one time, and use "select FILEHANDLE" on one, then another, you're inviting confusion about where a given 'print $string' is really going.
  • When your print statements are using the same string over and over (e.g. '<DOCTYPE>...'), it makes sense to assign that string to a variable, and use the variable in all those print statements.
  • Try to write a brief, simple pseudo-code version of your app, and see if it leads you to compartmentalize things a little better (e.g. to put some portions of code into subroutines).

I don't know why you got the error that you reported (earlier comments about an open failure that you didn't check for are probably on the mark), but I would like to offer this pseudo-code summary as an example that arranges things a little differently and may suggest some ways to write the code more economically:
connect_to_db or die prepare_query or die open_master_page or die print_master_page_header $artist_page_open = ""; while ( query_returns_a_row ) { if ( $artist_page_open ne this_artist ) { if ( $artist_page_open ne "" ) { print_artist_page_trailer close_artist_page or die } open_artist_page or die print_artist_page_header $artist_page_open = this_artist } print_artist_page_row print_master_page_row } close_db print_artist_page_trailer print_master_page_trailer
I'm not saying everything should be a subroutine; but as you start to put details into the stubs and you find things that they have in common, it'll be easier to factor those common things into subs, so you only have to code each one once.

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Re: Question about Open and Close
by Ebany (Sexton) on Jun 09, 2002 at 19:43 UTC
    I had actually wanted to write things in subprocedures, as it's the way I usually do things when programming, because it makes for more readable code, however I was then having problems with printing. I found that if I created an "artistBreak" sub and "albumBreak" sub, and then tried to print from within those subprocedures, I got errors trying to print. I was a little confused if I should open the artist page again within the subprocedure, and then seek to the end and print, or if I should somehow be able to declare an open on the global level, and then print normally. I was also debating if it would be more "proper" to do all "print ALBUMMASTER 'blah blah'" or the way I did, doing a select, and then switching when needed. I agree with you though, it should be cleaned up, and broken into smaller pieces.

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