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| From | Ian Collins <ian-news@hotmail.com> |
|---|---|
| Newsgroups | comp.lang.c |
| Subject | Re: Is this poor style? |
| Date | 2015-01-08 11:10 +1300 |
| Message-ID | <ch5p66FpgmlU8@mid.individual.net> (permalink) |
| References | (2 earlier) <57491de8-6480-47d1-b876-86236262e3da@googlegroups.com> <Y_kqw.363096$be7.149990@fx14.am4> <Dolqw.330807$fX6.290031@fx26.am4> <slrnmam2fv.4et.grahn+nntp@frailea.sa.invalid> <sFPqw.487139$7A5.252993@fx17.am4> |
BartC wrote: > On 05/01/2015 22:02, Jorgen Grahn wrote: >> On Mon, 2015-01-05, BartC wrote: >>> On 05/01/2015 00:35, Richard Heathfield wrote: >> ... >>>> Whilst it is certainly true that I've heard that goto isn't good, I actually >>>> have personal experience of its not being good. >>> >>> You might, nevertheless, prefer reading other people's code that uses >>> gotos sensibly and consistently, to alternates that involve tortuous >>> logic or where the action keep shifting to dozens of extra functions >>> (with the complicated interfaces required to allow them to share common >>> data). >> >> I think I was the one who mentioned using functional decomposition >> instead of goto. I can assure you, that doesn't end up as "dozens of >> extra functions", "complicated interfaces" or shared common data. > > Could you take any function, and turn any block of block within it into > a second function? Could you do that several times to create several new > functions? Yes, it is a common refactoring known as "extract method". > I would have these problems: > > (1) I would need to think of meaningful names for these function, ones > that are unique because now I'm in the global name-space. Not if they are static. If the block of code is doing something specific (which is why you are extracting it), choosing a name should be straightforward. > (2) I would need to decide where to place those functions. Perhaps the > original function was part of nice, tidy cluster with related > functionality, but it's not going to be tidy much longer! Indeed, it will be tidier once all the clutter is removed... > (3) I'd need to document the functions and explain why each is only > called from one place. Also what it actually does which is harder > because it might not be meaningful outside its original context Very often the cue to extract a function is the need to comment a block of code, so (if it is still required) the comment can go with it. Choosing a meaningful name for the function will often remove the need for the comment. Why would you have to explain why it is called from one place? > (4) I'd have to document the new calls in the original function. Why? Isn't calling them clear enough? > (5) If the blocks of code made use of local variables (using or setting > their values) then this is where the interface between the original > function and the new splinter functions can get awkward (not to mention > inefficient unless inlined. But relying on inlining a function you went > to all that trouble to 'out-line' seems perverse!). In that case there are a couple of options: 1) do nothing 2) if there aren't too many, pass the local variables as parameters 3) if there will be several functions working on the same data, consider using a struct. > (6) If the code is under development, this gets more hairy if it now > involves statements being moved across functions. (Imagine trying to > reorganise your bookshelves but half your books are now with your > neighbours.) Eh? If the code is under development, isn't it easier to test smaller chunks? > (7) If I want to move the entire function, I now have all these extra > dependencies. And any tools that lists all the functions is going to > cluttered with all these new functions with ill-defined roles. Surely the roles are well defined, which is why you extracted the functions in the first place. > In short, creating all this mess for the sake of a avoiding gotos is > crazy. (There are ways of encapsulating blocks of code but keeping them > within the function, such as local functions or something like the 'flow > blocks' that Rick was on about, but those are not standard.) More often than not functions are extracted to simplify and improve the code, not to avoid a goto. If you work with small functions from the beginning, you are far less likely to end up with a function the uses goto. -- Ian Collins
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Is this poor style? "S.K.R. de Jong" <SKRdJ@nowhere.net> - 2015-01-04 00:46 +0000
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-03 16:58 -0800
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-04 20:37 +1300
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-04 02:32 -0800
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-05 09:39 +1300
Re: Is this poor style? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-04 22:53 +0000
Re: Is this poor style? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-01-04 01:29 +0000
Re: Is this poor style? Morris Dovey <mrdovey@iedu.com> - 2015-01-04 00:00 -0600
Re: Is this poor style? Morris Dovey <mrdovey@iedu.com> - 2015-01-04 02:20 -0600
Re: Is this poor style? August Karlstrom <fusionfile@gmail.com> - 2015-01-04 15:46 +0100
Re: Is this poor style? Ike Naar <ike@iceland.freeshell.org> - 2015-01-04 15:10 +0000
Re: Is this poor style? August Karlstrom <fusionfile@gmail.com> - 2015-01-04 17:06 +0100
Re: Is this poor style? Clark Smith <noaddress@nowhere.net> - 2015-01-04 15:30 +0000
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-04 07:44 -0800
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-05 00:35 +0000
Re: Is this poor style? BartC <bc@freeuk.com> - 2015-01-05 01:02 +0000
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-05 01:43 +0000
Re: Is this poor style? BartC <bc@freeuk.com> - 2015-01-05 11:35 +0000
Re: Is this poor style? raltbos@xs4all.nl (Richard Bos) - 2015-01-05 12:58 +0000
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-05 13:14 +0000
Re: Is this poor style? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-05 22:02 +0000
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-05 14:24 -0800
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-06 12:26 +1300
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-06 02:40 -0800
Re: Is this poor style? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-07 19:32 +0000
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-07 20:03 +0000
Re: Is this poor style? BartC <bc@freeuk.com> - 2015-01-07 20:27 +0000
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-08 09:55 +1300
Re: Is this poor style? Les Cargill <lcargill99@comcast.com> - 2015-01-07 18:13 -0600
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-08 13:17 +1300
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-07 21:02 +0000
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-08 11:22 +0100
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-08 11:33 +0000
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-08 13:08 +0100
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-08 12:54 +0000
Re: Is this poor style? David Brown <david.brown@hesbynett.no> - 2015-01-08 14:04 +0100
Re: Is this poor style? Keith Thompson <kst-u@mib.org> - 2015-01-07 13:57 -0800
Re: Is this poor style? Les Cargill <lcargill99@comcast.com> - 2015-01-07 18:12 -0600
Re: Is this poor style? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-01-07 20:56 +0000
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-07 21:18 +0000
Re: Is this poor style? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-07 21:28 +0000
Re: Is this poor style? BartC <bc@freeuk.com> - 2015-01-06 11:28 +0000
Re: Is this poor style? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-07 20:19 +0000
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-07 16:05 -0800
Re: Is this poor style? glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-01-08 08:29 +0000
Re: Is this poor style? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-12 22:08 +0000
Re: Is this poor style? Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-24 20:35 -0700
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-03-25 08:43 -0700
Re: Is this poor style? Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-25 16:38 -0700
Re: Is this poor style? Stephen Sprunk <stephen@sprunk.org> - 2015-03-26 15:43 -0500
Re: Is this poor style? Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-28 08:57 -0700
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-08 13:23 +1300
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-07 16:53 -0800
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-08 14:11 +1300
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-08 11:10 +1300
Re: Is this poor style? John Bode <jfbode1029@gmail.com> - 2015-01-05 15:54 -0800
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-06 11:03 +0100
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-06 11:10 +0100
Re: Is this poor style? John Bode <jfbode1029@gmail.com> - 2015-01-06 06:03 -0800
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-06 14:44 +0000
Re: Is this poor style? "Osmium" <r124c4u102@comcast.net> - 2015-01-06 09:10 -0600
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-08 11:14 +0100
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-08 11:31 +0000
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-08 13:06 +0100
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-08 13:19 +0100
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-08 12:53 +0000
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-08 05:49 -0800
Re: Is this poor style? Keith Thompson <kst-u@mib.org> - 2015-01-08 08:18 -0800
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-09 07:58 +0100
Re: Is this poor style? Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-24 09:28 -0700
Re: Is this poor style? Keith Thompson <kst-u@mib.org> - 2015-03-24 13:57 -0700
Re: Is this poor style? Tim Rentsch <txr@alumni.caltech.edu> - 2015-03-25 08:28 -0700
Re: Is this poor style? Keith Thompson <kst-u@mib.org> - 2015-03-25 12:17 -0700
Re: Is this poor style? Öö Tiib <ootiib@hot.ee> - 2015-04-05 17:03 -0700
Re: Is this poor style? John Bode <jfbode1029@gmail.com> - 2015-01-14 11:25 -0800
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-14 19:41 +0000
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-15 09:01 +0100
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-15 09:35 +0100
Re: Is this poor style? James Kuyper <jameskuyper@verizon.net> - 2015-01-04 11:15 -0500
Re: Is this poor style? Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-01-04 21:38 +0000
Re: Is this poor style? Dr Nick <nospam-4@temporary-address.org.uk> - 2015-01-05 07:27 +0000
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-05 06:33 -0800
Re: Is this poor style? Vincenzo Mercuri <nomail@yahoo.it> - 2015-01-04 18:56 +0100
Re: Is this poor style? rouben@shady.(none) (Rouben Rostamian) - 2015-01-04 18:22 +0000
Re: Is this poor style? Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-01-04 21:35 +0000
Re: Is this poor style? Ian Collins <ian-news@hotmail.com> - 2015-01-05 10:46 +1300
Re: Is this poor style? Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-01-04 15:36 -0800
Re: Is this poor style? asetofsymbols@gmail.com - 2015-01-05 12:05 -0800
Re: Is this poor style? asetofsymbols@gmail.com - 2015-01-05 14:18 -0800
Re: Is this poor style? asetofsymbols@gmail.com - 2015-01-05 14:32 -0800
Re: Is this poor style? asetofsymbols@gmail.com - 2015-01-05 14:37 -0800
Re: Is this poor style? James Kuyper <jameskuyper@verizon.net> - 2015-01-05 18:23 -0500
Re: Is this poor style? Richard Heathfield <invalid@see.sig.invalid> - 2015-01-05 23:32 +0000
Re: Is this poor style? Keith Thompson <kst-u@mib.org> - 2015-01-05 15:31 -0800
Re: Is this poor style? Phil Carmody <pc+usenet@asdf.org> - 2015-01-13 15:00 +0200
Re: Is this poor style? Les Cargill <lcargill99@comcast.com> - 2015-01-04 15:07 -0600
Re: Is this poor style? jadill33@gmail.com - 2015-01-05 15:03 -0800
Re: Is this poor style? buja <buja66@gmail.com> - 2015-01-06 21:48 +0100
Re: Is this poor style? Rosario193 <Rosario@invalid.invalid> - 2015-01-08 11:21 +0100
Re: Is this poor style? buja <buja66@gmail.com> - 2015-01-08 12:42 +0100
Re: Is this poor style? "S.K.R. de Jong" <SKRdJ@nowhere.net> - 2015-01-08 15:29 +0000
Re: Is this poor style? James Kuyper <jameskuyper@verizon.net> - 2015-01-08 12:03 -0500
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