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

.net - C# List<T>.Find(x=>x.Rectangle.Contains(Point)) FAIL -

For my life, I can not understand why this code generates the following output ... I think there is a bug or something while using the list and lambda, if type one rectangle exposes the property and you use the included method of rectangle object ... and the clear statement proves true while Find list method fails .... Onway Code Public Gridskeyr Warldtokapadsb (Point location) {location = _Map.WorldToClient (location); Gridsquare gs = this.find (x => x.Rectangle.Contains (location)); GridSquare KP = G.Find (X => X. laxative canteen (location)); & Lt; GridSquare & gt; List = kp.FindAll (x => x.Rectangle.Contains (location)); U.dp (list.Count); Gridskare sub = KP.Fid (X => X. laxative canteen (location)); If (sub == faucet) {u.dp (place to look for "location"); U.dp ("The location found in the grid category" + GS toaster ()); U.dp ("Grid Square Bounds" + gs.Rectangle.ToString ()); U.dp ("location found in keypad" +...
Read more

iphone - Smoothing a rounded stroke in Core Graphics -

I am making my own UITableViewCells with a gradient background. I have worked all the logic and drawing, but the one that I want to fix is ​​"chunky" around the corners of my custom cell: If you have corners, you See what I'm talking about. Here is the code that I am using to generate cells: CGCTXT C = UigRxGroupCertexConnect (); CGColorSpaceRef myColorSpace = CGColorSpaceCreateDeviceRGB (); CGGradientRef myGradient = Zero; CGFloat component [8] = TABLE_CELL_BACKGROUND; CGContextSetStrokeColorWithColor (C, [[UAColor colorWithWhite: 0.7 alpha: 1] CGColor]); CGContextSetLineWidth (C, 2); CGContextSetAllowsAntialiasing (C, Yes); CGContextSetShouldAntialias (C, Yes); CGFloat minx = CGRectGetMinX (RECT), MIDX = CGRactgetMIDX (RECT), MAX x = CGTXxX (RECT); CGFloat miny = CGRectGetMinY (Rect), maxy = CGRectGetMaxY (rect); CGMutablePathRef Path = CGPathCreateMutable (); CGPathMoveToPoint (path, NULL, minx, miny); CGPathAddArcToPoint (default margin of path, NULL, mix, ...
Read more

Best practice for URL redirection in ASP.NET web application -

I have an asp page (Default.aspx) that shows the difference between two text files. It has two drop down lists (respectively id = "file1" and "file2" respectively) and a button (id = "submit"). There is also a lexical control with the id "result". The content of the list button is populated based on the files present in the physical application path. Each time the submit button is clicked, I want to give the result of diff / comparison in literal control, so I have an event handler like this: protected Zero Submit_Click (Object Sender, EventArgs e) {Results.First = Comparison Files (File 1. Selected Price, File2.SelectedValue); } The problem with this is that you can not bookmark results of comparison between specific files. To solve this problem, I compare the values ​​of the selected files as a query string for the added URL and made a redirection. And so, the above event handler has been changed to look like this: Protecte...
Read more