Re: File handles and loops

I think you mingle the validation code and the user interaction code too much. Here's a somewhat cleaner version...

use 5.010;
use strict;
use warnings;

{
    package Local::File;
    
    use Any::Moose;
    use overload q[""] => \&contents;
    
    has filename => (
        is       => 'ro',
        isa      => 'Str',
        required => 1,
    );
    
    sub open
    {
        my $self = shift;
        my $mode = shift // '<';
        open my $fh, $mode, $self->filename
            or confess sprintf(
                "could not open '%s' in '%s' mode: $!",
                $self->filename,
                $mode,
            );
        return $fh;
    }
    
    sub init
    {
        my $fh = shift->open('>');
        say $fh $_ for qw(
            howdy partner goodbye Friend saynora adios Amigo
        );
    }
    
    sub edit
    {
        system($ENV{EDITOR}, shift->filename);
    }
    
    sub errors
    {
        my $fh = shift->open;
        my @errors;
        while (<$fh>)
        {
            next if /^[a-z]/;
            chomp;
            push @errors, qq{Line does not begin with lower-case lette
+r, syntax error on line $. ("$_")};
        }
        return @errors;
    }

    sub contents
    {
        my $fh = shift->open;
        local $/ = undef;
        return <$fh>;
    }
}


my $file = Local::File::->new(filename => '/home/tai/tmp/my-file.txt')
+;
$file->init;
while (my @errors = $file->errors)
{
    say for @errors;
    say "please press ENTER to edit file";
    <STDIN>;
    $file->edit;
}

say "Valid file!";
say $file;
[download]

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

Comment on Re: File handles and loops Download Code

Replies are listed 'Best First'.
Re^2: File handles and loops by dr.jekyllandme (Sexton) on Jul 31, 2012 at 21:37 UTC
Hi tobyink, Thank you for replying. You, Neighbour, and the other Monks really helped me out. But I wanted to ask you how should I close the filehandle $fh after it has been opened? I've written my code somewhat similar to you and Neighbours but I am not sure if it is correct. Here is a snippet of the problem: `sub my_close { my( $fh ) = @_; + close($fh) or die "$!\n"; } + sub my_open { + my( $file, $mode ) = @_; + open my $fh, $mode, $file or die "$!\n"; + return $fh; } sub errors { + my( $file, $mode ) = @_; my $fh = my_open($file, $mode); my @errors = (); while( <$fh> ) { chomp; + next if /^[a-z]/; push( @errors, qq(Line $. '$_' does not begin with lowercase l +etter.) ); } my_close($fh); # Safe to close file like this??? + + return @errors; }` [download] Thank you.	[reply] [d/l]
Re^3: File handles and loops by tobyink (Canon) on Aug 01, 2012 at 06:29 UTC
You rarely need to close lexical file handles. They automatically close once the variable goes out of scope. That is, if the `my $fh` is defined within a function, then once that function finishes executing, the file handle disappears. `perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'`	[reply] [d/l]