Perl Syntax - What's the difference?

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

DBIC code used to work - using Moose, DBIC and DateTime (ymd(), and month_name()):

print $event->startdate->ymd(), " - ", $event->startdate->month_name()
+;
[download]

and now the DB schema changed (underscore introduced in column names):

print $event->start_date->ymd(), " - ", $event->start_date->month_name
+();
[download]

and now it does not:

Can't locate object method "ymd" via package "2008-08-18" (perhaps you
+ forgot to load "2008-08-18"?) at ./test-dbic-schema.pl line 50.
[download]

So what's the difference? Why should the underscore throw this out? What is the correct syntax/escaping for this stuff (Perl has kooki syntax sometimes)...

Comment on Perl Syntax - What's the difference? Select or Download Code

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Re: Perl Syntax - What's the difference? by Corion (Patriarch) on Apr 09, 2018 at 11:50 UTC
Most likely this is because somewhere in your setup/configuration, there is something that tells Moose / DBIC / whatever to map values from a column `startdate` to DateTime objects. But now the column is named `start_date` and that list has not been adjusted appropriately. Alternatively, the column type has changed to something that the hidden magic of Moose / DBIC / whatever cannot determine that you want DateTime objects from what was a `date` column anymore. Or maybe it's now a `timestamp` column. Maybe reducing your zoo of modules to a simple case of one table with two columns, `startdate` and `start_date` that still fails to magically inflate one column but magically inflates the other column can help us to give you better advice.	[reply] [d/l] [select]
Re^2: Perl Syntax - What's the difference? by Galdor (Sexton) on Apr 09, 2018 at 12:13 UTC
ok Corion - you da man! - Youre reponse pushed me in the right directions - for more investigations. Wow wasted an hour on that... It appears that the original scripts had this included: `> __PACKAGE__->load_components( qw/InflateColumn::DateTime /);` [download] and newly generated ones not - it seems to be the way that the DBIC was generated from the Pg schema - there is a script (that I used) that does not add this "pacakge" and there are some notes in a readme to do: `dbicdump -o components='["InflateColumn::DateTime"]' \` [download] so I guess that was it - not even in the source code! Who new?! Thanks once again for the steer..	[reply] [d/l] [select]
Re: Perl Syntax - What's the difference? by Your Mother (Archbishop) on Apr 09, 2018 at 12:20 UTC
Corion is right. It's not a Perl syntax issue, it's configuration. Probably it's one of two things. You regenerated your schema so you lost the custom code/config or you need to `s/startdate/start_date/` in the inflation definition in your Result package matching the table that holds the column. You are either using DBIx::Class::InflateColumn::DateTime to inflate the column or doing it a bit more manually with DBIx::Class::InflateColumn; the second option seems more likely because the column name is repeated. Use the docs against your own .pm file and you should be able to fix it easily. Update: didn't see you'd worked it out before posting.	[reply] [d/l]
Re: Perl Syntax - What's the difference? by LanX (Saint) on Apr 09, 2018 at 12:06 UTC
> Can't locate object method "ymd" via package "2008-08-18" probably you have code where you use ymd without brackets? `DB<4> $a="2008-08-18" DB<5> ymd $a Can't locate object method "ymd" via package "2008-08-18" (perhaps you + forgot to load "2008-08-18"?) at (eval 10)[/usr/share/perl/5.18/perl +5db.pl:732] line 2.` [download] Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Wikisyntax for the Monastery}	[reply] [d/l]
Re^2: Perl Syntax - What's the difference? by Corion (Patriarch) on Apr 09, 2018 at 12:08 UTC
There is no code (as posted) where `ymd $foo` is shown. The error message occurs for any string that gets used as a class/object without being blessed.	[reply] [d/l]
Re^3: Perl Syntax - What's the difference? by LanX (Saint) on Apr 09, 2018 at 12:47 UTC
The OP said the only thing he changed where "underscore introduced in column names" , so consequently I expected some side effects in code he is executing behind the scene. Cheers Rolf _{(addicted to the Perl Programming Language and ☆☆☆☆ :) Wikisyntax for the Monastery}	[reply]
Re^4: Perl Syntax - What's the difference? by Corion (Patriarch) on Apr 09, 2018 at 12:56 UTC
Re^5: Perl Syntax - What's the difference? by LanX (Saint) on Apr 09, 2018 at 13:09 UTC


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