October 2009 Archives

翻(雖然並沒有紙) 了一下 Passenger 的 Apache 文件，注意到一些可能可以用的選項，做了一些嘗試後，心得如下

From time to time I’m just being lazy to properly declare module dependencies in Makefile.PL, I do this to install required perl modules:

 cpanp -i `grep "^use " -r lib -h |cut -b 5-80|perl -pe 's/[ ;].*$//'|grep -v -E '(utf8|warnings|strict)' | sort | uniq`

This command should work with bash and zsh. Of course it does not cover all cases, it is just a cute, with certain definition of, hack.

Just played Plack a bit and get a crufty app.psgi for Jifty apps. This can be placed in your Jifty app dir and run with plackup --app app.psgi, but you’ll have to modify the line that sets JIFTY_APP_ROOT environment variable to your Jifty app path.

I hope this, and Jifty core, can be polished little bit so I don’t have to localize *ENV and *STDOUT there.

Also, I tried this with mod_psgi, not working, always returning ABORT from dispatcher, very weird.

Keep hacking.

Perl 5.11 多了一個「好棒好棒運算子 (Yada Yada Operator)」，寫做「…」(點點點)。它的做用是讓程式設計師能有效註明「這裡我還沒寫好」。如：

sub difficult_function { ... }
difficult_function();

此程式輸出如：

Unimplemented at yada.pl line 1.

從此之後大家可以放心在範例程式裡寫點點點了。

Update: 如果有人好奇這個運算子為何叫做「Yada Yada」，那是因為這個片語的意思便是「無聊、空泛的言語」之意(參考這裡)，跟「blah blah」一樣。本文標題戲譯為「好棒好棒」是取「Yatta!」這個日文表情之諧音，不過顯然會有些誤導，特此加註。

Jesse Vincent 發佈了 Perl 5.11.0 版本，這是一個「開發型」版本。其目的在於漸進而確實地發展出 Perl 5.12 版，並且，在到達之前，讓開發者能以未來版的 Perl 測試自己的程式，確保相容無誤。

為了契合此目的，發佈流程也做了許多調整。整個 5.11.x 版的發佈流程將以月為單位，每個月 20 號都會釋出一次新版，下一版 5.11.1 的釋出日期是十月20日，5.11.2 則為十一月 20 日。

我在此鼓勵各位立刻開始安裝 5.11 版的 Perl，並以其測試自己的程式。為了避免與已安裝在系統上的 Perl 衝突，可參考 Install perl to $HOME 這篇文章的做法，將 Perl 安裝到指定目錄去。

It is possible to write such sigil-less perl program:

foo = 42;
say foo;

The trick is to declare foo as a lvalue sub:

my $foo;
sub foo :lvalue { $foo }

Since $foo is a scalar, it works for hashref and arrayref too:

foo = { ans => 42 };
say foo->{ans}
# => 42

foo = [42, 43, 44]
say foo->[0]
# => 42

This appears to me an interesting smell of a new PerlX module.