Feature #12194: File.dirname optional parameter

• Status: Closed
• Assignee: -
• Target version: -

[nobu (Nobuyoshi Nakada)]

As talked at the last developers' meeting, I propose an addition of an optional parameter to File.dirname.

Often I see the code, like

File.dirname(File.dirname(path)) # or
File.expand_path("../..", path)

which are not concise.

This proposal can make them as:

File.dirname(path, 2)

Patch

[vo.x (Vit Ondruch)]

• Subject changed from File.dirname optonal parameter to File.dirname optional parameter

[Eregon (Benoit Daloze)]

Using Pathname would already make this much nicer:

Pathname(path).parent.parent

And less error prone than File.dirname if the path is not absolute.
Just my opinion, but I do not like this particular syntax.

[shevegen (Robert A. Heiler)]

I myself have found Pathname harder or less elegant to use than the direct File* or Dir* methods so I am in support of the suggestion by nobu.

So to Benoit, I understand that you may consider File.dirname(path, 2) not ideal either (a user may wonder what the 2 means), the alternative
suggestion to use Pathname is not ideal either and additionally requires one to require pathname for that toplevel Pathname() method and
subsequent use of pathname:

require 'pathname'
# require 'fileutils'; FileUtils.mkdir_p('/tmp/foobar/') # <-- this line just for testing purpose, disregard it
Pathname("/tmp/foobar/").parent.parent.to_s # => "/"

Being able to directly do so on File.dirname() itself is good, in my opinion.

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)

[mame (Yusuke Endoh)]

Matz has already accepted this proposal at the previous meeting.

https://github.com/ruby/dev-meeting-log/blob/master/DevelopersMeeting20210216Japan.md#feature-12194-filedirname-optional-parameter-nobu

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Closed

Applied in changeset git|82b6f89283042b670975f3f7986432647101984e.

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File.dirname optional level

• file.c (rb_file_dirname_n): chomp N level of base names.
  [Feature #12194]