From ruby-talk-admin@ruby-lang.org Fri Dec 16 02:04:22 2005 Received: from kankan.nagaokaut.ac.jp (kankan.nagaokaut.ac.jp [133.44.2.24]) by blade.nagaokaut.ac.jp (8.12.3/8.12.3/Debian-6.6) with ESMTP id jBFH4MZk028694; Fri, 16 Dec 2005 02:04:22 +0900 Received: from funfun.nagaokaut.ac.jp (funfun.nagaokaut.ac.jp [133.44.2.201]) by kankan.nagaokaut.ac.jp (Postfix) with ESMTP id 9A30D5A3E; Fri, 16 Dec 2005 02:04:26 +0900 (JST) Received: from localhost (localhost.nagaokaut.ac.jp [127.0.0.1]) by funfun.nagaokaut.ac.jp (Postfix) with ESMTP id 91541F04842; Fri, 16 Dec 2005 02:04:26 +0900 (JST) Received: from voscc.nagaokaut.ac.jp (voscc.nagaokaut.ac.jp [133.44.1.100]) by funfun.nagaokaut.ac.jp (Postfix) with ESMTP id 41416F04850; Fri, 16 Dec 2005 02:04:25 +0900 (JST) Received: from beryllium.ruby-lang.org (beryllium.ruby-lang.org [210.163.138.100]) by voscc.nagaokaut.ac.jp (Postfix) with ESMTP id 2DDA863002E; Fri, 16 Dec 2005 02:04:25 +0900 (JST) Received: from beryllium.ruby-lang.org (beryllium.ruby-lang.org [127.0.0.1]) by beryllium.ruby-lang.org (Postfix) with ESMTP id 5CD2533D09; Fri, 16 Dec 2005 02:04:24 +0900 (JST) Received: from localhost (beryllium.ruby-lang.org [127.0.0.1]) by beryllium.ruby-lang.org (Postfix) with ESMTP id A0A2E33D9B for ; Fri, 16 Dec 2005 02:04:16 +0900 (JST) Received: from beryllium.ruby-lang.org ([127.0.0.1]) by localhost (beryllium.ruby-lang.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 09091-02 for ; Fri, 16 Dec 2005 02:04:16 +0900 (JST) Received: from mail.gmx.net (mail.gmx.de [213.165.64.21]) by beryllium.ruby-lang.org (Postfix) with SMTP id A13BB33D09 for ; Fri, 16 Dec 2005 02:04:15 +0900 (JST) Received: (qmail 13417 invoked by uid 0); 15 Dec 2005 17:04:09 -0000 Received: from 62.225.37.69 by www1.gmx.net with HTTP; Thu, 15 Dec 2005 18:04:09 +0100 (MET) Delivered-To: ruby-talk@ruby-lang.org Date: Fri, 16 Dec 2005 02:04:17 +0900 Posted: Thu, 15 Dec 2005 18:04:09 +0100 (MET) From: "Peter Ertl" Reply-To: ruby-talk@ruby-lang.org Subject: Re: Assigning a block to a variable in Ruby To: ruby-talk@ruby-lang.org (ruby-talk ML) Message-Id: <21050.1134666249@www1.gmx.net> References: <1134665773.927049.245200@z14g2000cwz.googlegroups.com> X-ML-Name: ruby-talk X-Mail-Count: 68 X-MLServer: fml [fml 4.0.3 release (20011202/4.0.3)]; post only (only members can post) X-ML-Info: If you have a question, send e-mail with the body "help" (without quotes) to the address ruby-talk-ctl@ruby-lang.org; help= X-Mailer: WWW-Mail 1.6 (Global Message Exchange) X-Original-To: ruby-talk@ruby-lang.org X-Priority: 3 (Normal) X-Authenticated: #8402114 X-Flags: 0001 X-Virus-Scanned: by amavisd-new-20030616-p10 (Debian) at ruby-lang.org X-Spam-Checker-Version: SpamAssassin 3.0.3 (2005-04-27) on beryllium.ruby-lang.org X-Spam-Level: X-Spam-Status: No, score=-14.8 required=7.0 tests=AWL,BAYES_00,BLARS00, BLARS_SPAM00,CONTENT_TYPE_PRESENT,RCVDFRMLOCALIP,RCVD_IN_BLARS, RCVD_IN_BLARS_SPAM,RCVD_IN_BLARS_SPSPRT,X_MAILER_PRESENT autolearn=ham version=3.0.3 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8bit Precedence: bulk Lines: 73 List-Id: ruby-talk.ruby-lang.org List-Software: fml [fml 4.0.3 release (20011202/4.0.3)] List-Post: List-Owner: List-Help: List-Unsubscribe: X-Virus-Scanned: by AMaViS snapshot-20020531 Maybe you are looking for something like that? > p = lambda {|num| puts num } > p.call(123) 123 > --- Ursprüngliche Nachricht --- > Von: ajmayo@my-deja.com > An: ruby-talk@ruby-lang.org (ruby-talk ML) > Betreff: Assigning a block to a variable in Ruby > Datum: Fri, 16 Dec 2005 01:57:41 +0900 > > I am new to Ruby and curious as to how you emulate the following > Javascript snippet > (example in Windows, hence the call to Echo) > > var a = function(p) {WScript.Echo(p)} > > bar(a); > > function bar(z) > { > z(1); > WScript.Echo(z); > } > > which would of course create an anonymous function, assign it to > variable a, pass this as a parameter to function bar() and then > evaluate the function with parameter 1, then attempt to print the > function itself (which Javascript will do, printing the text of the > block) > > I found Ruby quite intuitive until I tried > > a = {some block} > > and found that this of course doesn't work as in this context {} refers > to a hash. > > Ok, that's fine, but the 'yield' statement seems very funky and Perlish > to me. Effectively a block passed to a routine exists as a 'hidden' > argument so that > > foo(100) {someblock} > > in Ruby passes one parameter explicitly (as we would see from foo's > defined argument list) and a 'hidden' block which 'yield' inside the > body of foo() would evaluate. > > (though, oddly, yield {someblock} is also not valid Ruby). > > This seems horribly inelegant for a language touted as being The Next > Great Thing. > > It is also unclear, how, then, I pass down a block as an argument and > then in turn pass it again to a child routine. > > I can see how a parameter to a block works - this is clearly borrowed > >from Smalltalk - but Javascript doesn't enforce separation of dynamic > code in the way Ruby appears to. > > At present Javascript's syntax looks much cleaner. Am I missing > something? > > Also, I presume Ruby is a forward-referencing language only, unlike > Javascript, where I can declare a function after code which calls it. > Ruby didn't seem to like that much. > >