Forum: Ruby-core [ruby-trunk - Bug #7440][Open] IO#lines etc. should return Array

Issue #7440 has been reported by yhara (Yutaka HARA).

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Bug #7440: IO#lines etc. should return Array
https://bugs.ruby-lang.org/issues/7440

Author: yhara (Yutaka HARA)
Status: Open
Priority: Normal
Assignee: yhara (Yutaka HARA)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2012-11-26 trunk 36708) [x86_64-darwin12.2.1]


String#bytes, #chars, #codepints and #lines are changed to return Array 
in #6670.

For consistent behavior, following methods should return Array too:

* ARGF.lines, chars, bytes, codepoints
* IO#lines, chars, bytes, codepoints
* StringIO#lines, chars, bytes, codepoints
* Zlib::GzipReader#lines, bytes

Please let me know if there are more.

Issue #7440 has been updated by headius (Charles Nutter).


Is this really wnat you'd want? ARGF and IO (and possibly Zlib's 
readers) can stream data lazily in lines/chars/bytes/codepoints, where 
forcing them to an Array would have to eagerly read everything (and 
potentially block).

irb(main):001:0> io = File.open('Makefile')
=> #<File:Makefile>
irb(main):002:0> lines = io.lines
=> #<Enumerator: #<File:Makefile>:lines>
irb(main):003:0> lines.next
=> "SHELL = /bin/sh\n"
irb(main):004:0> io.pos
=> 16
irb(main):005:0> lines.next
=> "NULLCMD = :\n"
irb(main):006:0> io.pos
=> 28
irb(main):007:0> lines.to_a; nil
=> nil
irb(main):008:0> io.pos
=> 12737

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Bug #7440: IO#lines etc. should return Array
https://bugs.ruby-lang.org/issues/7440#change-33970

Author: yhara (Yutaka HARA)
Status: Open
Priority: Normal
Assignee: yhara (Yutaka HARA)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2012-11-26 trunk 36708) [x86_64-darwin12.2.1]


String#bytes, #chars, #codepints and #lines are changed to return Array 
in #6670.

For consistent behavior, following methods should return Array too:

* ARGF.lines, chars, bytes, codepoints
* IO#lines, chars, bytes, codepoints
* StringIO#lines, chars, bytes, codepoints
* Zlib::GzipReader#lines, bytes

Please let me know if there are more.

Issue #7440 has been updated by drbrain (Eric Hodel).


With the exception of StringIO hey also support infinite streams. I 
think the current Enumerator is best.
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Bug #7440: IO#lines etc. should return Array
https://bugs.ruby-lang.org/issues/7440#change-33973

Author: yhara (Yutaka HARA)
Status: Open
Priority: Normal
Assignee: yhara (Yutaka HARA)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2012-11-26 trunk 36708) [x86_64-darwin12.2.1]


String#bytes, #chars, #codepints and #lines are changed to return Array 
in #6670.

For consistent behavior, following methods should return Array too:

* ARGF.lines, chars, bytes, codepoints
* IO#lines, chars, bytes, codepoints
* StringIO#lines, chars, bytes, codepoints
* Zlib::GzipReader#lines, bytes

Please let me know if there are more.

Issue #7440 has been updated by Eregon (Benoit Daloze).


drbrain (Eric Hodel) wrote:
> With the exception of StringIO hey also support infinite streams. I think the 
current Enumerator is best.

Strongly agreed. It could also increase a lot the memory usage (while on 
String we anyway already have the whole String in memory so it is less 
of a concern).

    File.open('/usr/share/dict/words').lines.each_with_object(Hash.new(0)) 
{ |word, count| count[word[0].downcase] += 1 }
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Bug #7440: IO#lines etc. should return Array
https://bugs.ruby-lang.org/issues/7440#change-33975

Author: yhara (Yutaka HARA)
Status: Open
Priority: Normal
Assignee: yhara (Yutaka HARA)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2012-11-26 trunk 36708) [x86_64-darwin12.2.1]


String#bytes, #chars, #codepints and #lines are changed to return Array 
in #6670.

For consistent behavior, following methods should return Array too:

* ARGF.lines, chars, bytes, codepoints
* IO#lines, chars, bytes, codepoints
* StringIO#lines, chars, bytes, codepoints
* Zlib::GzipReader#lines, bytes

Please let me know if there are more.

Issue #7440 has been updated by yhara (Yutaka HARA).


Eregon (Benoit Daloze) wrote:
> Strongly agreed. It could also increase a lot the memory usage (while on String 
we anyway already have the whole String in memory so it is less of a concern).
>
>     File.open('/usr/share/dict/words').lines.each_with_object(Hash.new(0)) { 
|word, count| count[word[0].downcase] += 1 }

In that case you can use IO#each_line, which still returns Enumerator.

     File.open('/usr/share/dict/words').each_line.with_object(Hash.new(0)) 
{ |word, count| count[word[0].downcase] += 1 }

But in other words, we need to replace uses of IO#lines to IO#each_line, 
or our existing Ruby program may have performance problem with 2.0.0...

# Ticket #6670 is reopened. Please continue discussion there 
http://bugs.ruby-lang.org/issues/6670
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Bug #7440: IO#lines etc. should return Array
https://bugs.ruby-lang.org/issues/7440#change-34002

Author: yhara (Yutaka HARA)
Status: Open
Priority: Normal
Assignee: yhara (Yutaka HARA)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2012-11-26 trunk 36708) [x86_64-darwin12.2.1]


String#bytes, #chars, #codepints and #lines are changed to return Array 
in #6670.

For consistent behavior, following methods should return Array too:

* ARGF.lines, chars, bytes, codepoints
* IO#lines, chars, bytes, codepoints
* StringIO#lines, chars, bytes, codepoints
* Zlib::GzipReader#lines, bytes

Please let me know if there are more.

Issue #7440 has been updated by yhara (Yutaka HARA).

Status changed from Open to Rejected

This issue is now included in #6670.
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Bug #7440: IO#lines etc. should return Array
https://bugs.ruby-lang.org/issues/7440#change-34227

Author: yhara (Yutaka HARA)
Status: Rejected
Priority: Normal
Assignee: yhara (Yutaka HARA)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2012-11-26 trunk 36708) [x86_64-darwin12.2.1]


String#bytes, #chars, #codepints and #lines are changed to return Array 
in #6670.

For consistent behavior, following methods should return Array too:

* ARGF.lines, chars, bytes, codepoints
* IO#lines, chars, bytes, codepoints
* StringIO#lines, chars, bytes, codepoints
* Zlib::GzipReader#lines, bytes

Please let me know if there are more.