triyng to built a module

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

Iam try built module to learn and teach perl, by practice, and I have the following bug:

#!/usr/bin/perl
use strict;
use warnings;

$char = chr(0x394);
$code = ord($char);

printf "char %s is code %d, %#04x\n", $char, $code, $code;
[download]

and it has this mistakes:

Global symbol "$char" requires explicit package name at 3.pl line 5.

Global symbol "$code" requires explicit package name at 3.pl line 6.

Global symbol "$char" requires explicit package name at 3.pl line 6.

Global symbol "$char" requires explicit package name at 3.pl line 8.

Global symbol "$code" requires explicit package name at 3.pl line 8.

Execution of 3.pl aborted due to compilation errors.

I will have more sample like this, pls help

Comment on triyng to built a module Download Code

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Re: triyng to built a module by toolic (Bishop) on Jul 22, 2013 at 18:57 UTC
Tip #1 from the Basic debugging checklist: use diagnostics: `(F) You've said "use strict" or "use strict vars", which indicates + that all variables must either be lexically scoped (using "my" or +"state"), declared beforehand using "our", or explicitly qualified to say which package the global variable is in (using "::").` [download] Declare all variables with my: `use strict; use warnings; my $char = chr(0x394); my $code = ord($char); printf "char %s is code %d, %#04x\n", $char, $code, $code;` [download] See also: perlintro UPDATE: Geez, this problem was solved for you a month ago :(	[reply] [d/l] [select]
Re: triyng to built a module by kennethk (Abbot) on Jul 22, 2013 at 18:57 UTC
The consequent of using strict is that you must either 'declare' variables with my or our, or use a fully qualified package name (see strict vars). The above code can be repaired with `#!/usr/bin/perl use strict; use warnings; my $char = chr(0x394); my $code = ord($char); printf "char %s is code %d, %#04x\n", $char, $code, $code;` [download] #11929 First ask yourself `How would I do this without a computer?' Then have the computer do it the same way.	[reply] [d/l]
Re: triyng to built a module by Loops (Curate) on Jul 22, 2013 at 19:10 UTC
Previous answers should get you to the point where your script runs, but you may then see a warning about printing wide characters. If this is the case, you can add the following to the top of your script to enable Unicode support: `use feature 'unicode_strings'; use open qw(:std :utf8); use utf8;` [download]	[reply] [d/l]
Re: triyng to built a module by davido (Cardinal) on Jul 22, 2013 at 19:39 UTC
`#!/usr/bin/perl use strict; # <--- Because of this... use warnings; use diagnostics; my $char = chr 0x394; #^-----------------------You must do this. (my) my $code = ord $char; #^----------------------- And this. (my)` [download] Dave	[reply] [d/l]
Re: triyng to built a module by Laurent_R (Canon) on Jul 22, 2013 at 21:07 UTC
Iam try built module to learn and teach perl, Do you seriously intend to teach Perl? It sounds sort of premature to me. Or perhaps it is a mistake in the English language... Or possibly you meant to teach yourself Perl...	[reply]
Re^2: triyng to built a module by Anonymous Monk on Jul 22, 2013 at 23:18 UTC
That's true, the examples are from a book, and I hope to help more people, i'm thinking in writting the examples to chapter 5, and put them online on my small website.	[reply]
Re^3: triyng to built a module by Anonymous Monk on Jul 23, 2013 at 01:19 UTC
PLEAC - Programming Language Examples Alike Cookbook	[reply]
Re: triyng to built a module by Anonymous Monk on Jul 25, 2013 at 15:34 UTC
If you want to learn how to do modules, I'd strongly suggest you getting and fully reading a book called "Object Oriented Perl" by Damian Conway. In addition to modules, the first 50 or so pages are a very good overview of Perl. I think you need to work thru that first before you head into modules ... although modules are a good goal. HTH...	[reply]
Re: triyng to built a module by wee (Scribe) on Jul 24, 2013 at 20:50 UTC
I'm sorry but this has to be the laziest submission I've seen in years. The very first result of a google search for "perl requires explicit package name at" will answer this "bug". Are we reduced to this?	[reply]
Re^2: triyng to built a module by Raymond (Novice) on Jul 25, 2013 at 15:18 UTC
No, I have more, should I put them all, or one at a time?	[reply]