How can I code in a functional style in Perl? -


आप या तो कैसे करते हैं:

  1. एक उप वापसी उप

    या

  2. कोड के रूप में पाठ निष्पादित

में

इसके अलावा, मैं कैसे एक अनाम समारोह स्टोर राज्य है?

एक उप coderef के रूप में एक उप देता है: 

  # उदाहरण 1: इनलाइन को परिभाषित किया गया एक उप वापसी उप foo {वापसी उप (मेरी $ this = shift; मेरा @other_परम = @_; कार्य करना(); वापसी $ some_value; }; } # उदाहरण 2: एक उप वापसी जिसे अन्यत्र परिभाषित किया गया है। उप बार {वापसी & amp; amp; foo; }

अनियंत्रित पाठ eval फ़ंक्शन के साथ निष्पादित किया जा सकता है: दस्तावेज को यहां देखें: 

  eval q {प्रिंट "हैलो दुनिया \ n "};

ध्यान दें कि यह बहुत खतरनाक है अगर आप उपयोगकर्ता इनपुट से निकाले गए कुछ चीजों का मूल्यांकन कर रहे हैं, और आम तौर पर एक खराब अभ्यास है, क्योंकि आप आम तौर पर अपने कोड को परिभाषित कर सकते हैं ऊपर दिए गए उदाहरणों में जैसा coderef।

आप राज्य को एक (नई perl5.10 में) स्टोर कर सकते हैं, या एक चर के साथ, उप के मुकाबले अधिक स्कॉक्ड के साथ: 

  सुविधा 'राज्य' का उपयोग करें; उप बाज़ {राज्य $ x; वापसी ++ $ x; } # एक नया अवसर बनाओ ताकि $ y इस पैकेज में अन्य कार्यों के लिए दृश्यमान न हो {my $ y; उप quux {वापसी ++ $ y; }}

Comments

Post a Comment

Popular posts from this blog

sql - dynamically varied number of conditions in the 'where' statement using LINQ -

I am using my first project LINQ (in mvc), so maybe there's something very simple that I remember. However, a day of searching and experimenting does not work, so it works. I am trying to write a LINQ query (Linux to SQL) in which in many cases where the statement is different from an OR or an AND. We do not know how many conditions are going in the query till runtime. This search is for filter control, where the user can choose multiple criteria for filtering. Select from table where table.col = 1 or table.col = 2 or table.col = 7 .... 'Other number of conditions Before I just create the SQL query as a string, while looping over all the situations. However, it seems that there should be a good way to do this in LINQ. I tried to use Expression trees, but they had a second thought for this moment on my head, where the lambda function was to be executed inside the statement such as: values ​​for matchingRows = matchingRows for each value Where (function (row) row.c...
Read more

asp.net mvc - Dynamically Generated Ajax.BeginForm -

I have a problem with ASP.NET MVC Ajax forms. I generate many Ajax form in a table such as: & Lt; Input type = "submit" name = "activity" value = "add activity" / & gt; & Lt;%}% & gt; & Lt; / TD & gt; & Lt; / TR & gt; & Lt;%}% & gt; So far so good. When I post one of those forms, it gives a partial view in a div, and in this new partial view a new Ajax Beginnform (which is not in Genesis form) This second Ajax Beginnorf is exactly like the ones I got on the table, but when I post it, I do not get the "Ajax Post", but a normal post that sends me to a new page, I do not know whether the two Ajax forms What is the reason for the difference between, why is it the "dynamically generated" Ajax form behaves like a normal HTML form? By the way, I know that I can do it in different ways using javascript, but I would like to understand whether it can only be done using MVC helplars and Ajax lib...
Read more

Debug on symbian -

I am using trk for phone debug This works well for the Holorld project But when I start the project in phone debug mode 1) the load failed 2) TrkProtocolPlugin: to target the specified file Failure (please verify If any body understands what problem I am experiencing, then this problem helps me Pre-release If the application has the privileges assigned (with the appropriate certificate) itemprop = "text" > In your case, I will check: / li> If there is no conflict of application ID with any other application of device If there are problematic commands in the installation package (for example copy copy for non-accessible directories)
Read more