# Re: Non-declared variables **URL:** \ **Category:** Ruby\ **Created:** [October 16, 2006, 5:10pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340 "2006-10-16T17:10:17Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [October 16, 2006, 5:10pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340/1 "2006-10-16T17:10:17Z")
From: Avatar [[mailto:removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)] > Are there real tangible benefits that non-declared, dynamically typed > (at binding time) variables provide? Or do dynamic variables simply > create less compile time errors and more (harder to catch) runtime > errors? Every language feature that reduces how much typing I have to do is a tangible benefit to me. It eases stress on my body machine, and speeds the delivery of my code. The only downside I can think of is that typos may not be caught for instance/class variables as readily: class Foo def bar @somethingDelicious = 12 end def whee print( @sonethingDeIicious ) end end If you personally find that you are having trouble in this arena, I suspect that it wouldn’t be hard to write a code analyzer that alerted on potential misspellings. I’ve personally not needed it. ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [October 16, 2006, 5:30pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340/2 "2006-10-16T17:30:22Z")
On Tue, 17 Oct 2006, Gavin K. wrote: > The only downside I can think of is that typos may not be caught for > > If you personally find that you are having trouble in this arena, I > suspect that it wouldn’t be hard to write a code analyzer that alerted > on potential misspellings. I’ve personally not needed it. for those of you using vim, the completion feature virtually eliminates this kind of bug. for instance, i can type @som, then hit ‘ctrl-n’, and @somethingDelicious simply appears. this is a huge bug stopper for me, because i reely cant spel. fyi. -a ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [October 16, 2006, 5:36pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340/3 "2006-10-16T17:36:29Z")
> Every language feature that reduces how much typing I have to do is a > tangible benefit to me. It eases stress on my body machine, and speeds > the delivery of my code. That seems a ridiculous thing to say to me. Time taken to type out code is not the limiting factor in your productivity. If you sacrifice readability, maintainibility, safety, extensibility or supportibility for a fewer characters, it’s hardly a worthwhile tradeoff. Terseness is not a virtue. If it were, I’d be a perl programmer. Martin ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [October 16, 2006, 5:48pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340/4 "2006-10-16T17:48:31Z")
On Oct 16, 2006, at 10:29 AM, removed\_email\_address@domain.invalid wrote: > > tangible benefit to me. It eases stress on my body machine, and > > def whee > > eliminates this > > kind of bug. for instance, i can type @som, then hit ‘ctrl-n’, and > > @somethingDelicious simply appears. this is a huge bug stopper for > > me, > > because i reely cant spel. In TextMate this is done with the escape key and I couldn’t agree more about it being an excellent habit to get into. James Edward G. II ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [October 16, 2006, 6:16pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340/5 "2006-10-16T18:16:43Z")
Gavin K. wrote: > If you personally find that you are having trouble in this arena, I > suspect that it wouldn’t be hard to write a code analyzer that alerted > on potential misspellings. Here’s a simple example I just came up with. (If this were to be taken a little further, it should probably report line numbers. If it were to be taken a lot further, it should probably use actual parsing of Ruby code to determine class scope for variables, leave out things that look like variables inside strings/regexp/comments, etc.) require ‘typochecker’ class Foo def foo @@name = ‘boot’ @name = ‘wow’ @somethingDelicious = 12 end def whee print( @mane, @@names ) print( @somethingDelicions ) end end #=\> Possible typo: @@name versus @@names #=\> Possible typo: @name versus @mane #=\> Possible typo: @somethingDelicious versus @somethingDelicions (typochecker.rb) # [http://po-ru.com/files/levenshtein/1.3/levenshtein.rb](http://po-ru.com/files/levenshtein/1.3/levenshtein.rb) require ‘levenshtein’ source = IO.read( $0 ) cvars, ivars = source.scan( /@{1,2}\w+/ ).partition{ |v| /^@@/ =~ v } [cvars, ivars].each{ |vars| vars.each\_with\_index{ |v1, i| vars[(i+1)…-1].each{ |v2| if Levenshtein.distance( v1, v2 ) \<= 2 warn “Possible typo: #{v1} versus #{v2}” end } } } ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [October 16, 2006, 6:49pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340/6 "2006-10-16T18:49:06Z")
> it’s not the actual typing of the lines that takes so long - it’s reasoning > over it. Yes, which is really my point. It’s not about reducing keystrokes. it’s about expressiveness. Martin ---
**Author:** ![phrogz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/p/2acd7d/32.png) [@phrogz](https://www.ruby-forum.com/u/phrogz)\ **Post date:** [October 16, 2006, 6:43pm UTC](https://www.ruby-forum.com/t/re-non-declared-variables/72340/7 "2006-10-16T18:43:05Z")
On Tue, 17 Oct 2006, Martin C. wrote: > Terseness is not a virtue. If it were, I’d be a perl programmer. > > Martin i translated a c option parer. this one: jib:~/shared/dmspnl\_new/grid\_ols \> wc -l commandline.h commandline.c 67 commandline.h 699 commandline.c 766 total it even uses getoptlong to reduce the busywork. in ruby it’s about 40 lines. it’s been proven (many times - google it) that programmers write the about the same number of lines of code per day regardless of the language, be it assembler or ruby. so, given that it might take be something like 30 minutes to produce a 40 line option parser in ruby, we can interpolate that the equivalent c parser would take about two and half days to produce. that’s quite expensive if you ask me, espcially considering that there is no good reason (speed for example) to parse options in c. it’s not the actual typing of the lines that takes so long - it’s reasoning over it. without even seeing the code i’m sure you’ll have no trouble believing that the ruby opt parser takes seconds to comprehend, while the c one takes considerably longer - simply based on it’s size. and this point isn’t even considering security faults, which have been shown to scale linearly with tloc. -a