# Comma separated lists syntax error **URL:** \ **Category:** Ruby\ **Created:** [December 13, 2007, 1:13am UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962 "2007-12-13T01:13:00Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 13, 2007, 1:13am UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/1 "2007-12-13T01:13:00Z")
I’m very disappointed that I cannot format my hashes like this { :a =\> 1 , :b =\> 2 , :c =\> 3 } The technique is popular in the haskell community; it has some obvious benefits over the traditional { :a =\> 1, :b =\> 2, :c =\> 3 } It doesn’t work in 1.9 either. ry ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 13, 2007, 1:35am UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/2 "2007-12-13T01:35:48Z")
On Dec 12, 5:11 pm, ry dahl [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > } > It doesn’t work in 1.9 either. For the same obvious reasons as you desire that, does it sufficiently please you that this alternate markup works: C:\>type tmp.rb h = { :a =\> 1, :b =\> 2, :c =\> 3, } p h C:\>ruby tmp.rb {:c=\>3, :a=\>1, :b=\>2} ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 13, 2007, 2:26am UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/3 "2007-12-13T02:26:42Z")
On 12/13/07, ry dahl [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > } > Just out of curiosity, what are those obvious benefits? It’s the first > time I’ve seen somebody prefer commas at the beginning of a new row. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 13, 2007, 2:27am UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/4 "2007-12-13T02:27:52Z")
No, the benefit is that the separators are at the beginning of the elements, aligned and in the same column so that it is easy to see one is not missing, you also don’t need to maintain the commas at the end of the line. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 13, 2007, 3:01am UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/5 "2007-12-13T03:01:50Z")
Andrei M. wrote: > > ``` > > :c => 3 > > > > ``` > > > > } > > Just out of curiosity, what are those obvious benefits? It’s the first > time I’ve seen somebody prefer commas at the beginning of a new row. I do this with C code. The idea is that you should make a continuation (here I use “continuation” to mean the 2nd and subsequent parts of a single statement that is broken over several lines) visually distinct by starting the continuation with a token that can’t legitimately start a new statement. I found the argument persuasive for C code. In Ruby, though, a comma at the end of a line is one of the ways to tell the parser that the statement is continued on the next line. Okay, different language, different rules. Nothing to get your panties in a wad about. Of course, I cut my teeth on FORTRAN, which used a non-blank character in column 1 to indicate a continuation, so my standards probably aren’t as high as they should be. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 13, 2007, 5:24am UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/6 "2007-12-13T05:24:43Z")
Hi, At Thu, 13 Dec 2007 10:26:21 +0900, ry dahl wrote in [ruby-talk:283285]: > No, the benefit is that the separators are at the beginning of the > elements, aligned and in the same column so that it is easy to see one > is not missing, you also don’t need to maintain the commas at the end > of the line. But you don’t have a comma before the first element. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 13, 2007, 6:47pm UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/7 "2007-12-13T18:47:21Z")
On Dec 12, 6:26 pm, ry dahl [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > p h > > > C:\>ruby tmp.rb > > {:c=\>3, :a=\>1, :b=\>2} > > No, the benefit is that the separators are at the beginning of the > > elements, aligned and in the same column so that it is easy to see one > > is not missing, you also don’t need to maintain the commas at the end > > of the line. Ah; I thought the ‘obvious’ benefit you were referring to was that you could copy/paste lines to change the order without having to remember to use commas after every element except the last. ---
**Author:** ![casper\_the\_ghost](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58956e/32.png) [@casper\_the\_ghost](https://www.ruby-forum.com/u/casper_the_ghost)\ **Post date:** [December 14, 2007, 8:10pm UTC](https://www.ruby-forum.com/t/comma-separated-lists-syntax-error/122962/8 "2007-12-14T20:10:56Z")
On Dec 13, 11:24 am, Phrogz [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > :b =\> 2, > > > of the line. > > Ah; I thought the ‘obvious’ benefit you were referring to was that you > could copy/paste lines to change the order without having to remember > to use commas after every element except the last. In haskell (mainly because of “layout”) and to a lesser extent, ocaml, people tend to format records (and such) with a syntax that commas line up with the opening/closing bracket, and appear on the line after the record field declaration. It makes kind of a visual “wall” between the name binding and the body of the declaration. It’s just a matter of taste and custom, and really, even with haskell, some people format their code differently. Regards, Jordan