Feature #749

String#indent, String#tabto, etc.

Added by trans (Thomas Sawyer) over 3 years ago. Updated 3 months ago.

[ruby-core:19885]
Status:Rejected Start date:11/13/2008
Priority:Normal Due date:
Assignee:matz (Yukihiro Matsumoto) % Done:

0%
Category:core
Target version:2.0.0

Description

There are few indention related String extensions I find myself frequently reusing. Ruby really has nothing built-in that addresses this, so I'd like to the following methods, or something like them, ultimately make it into Ruby core.

  # Preserves relative tabbing.
  # The first non-empty line ends up with n spaces before nonspace.
  def tabto(n)
    if self =~ /^( *)\S/
      indent(n - $1.length)
    else
      self
    end
  end

  # Indent left or right by n spaces.
  # (This used to be called #tab and aliased as #indent.)
  def indent(n)
    if n >= 0
      gsub(/^/, ' ' * n)
    else
      gsub(/^ {0,#{-n}}/, "")
    end
  end

  # Aligns each line n spaces.
  def tab(n)
    gsub(/^ */, ' ' * n)
  end

  # Provides a margin controlled string.
  #
  #   x = %Q{
  #         | This
  #         |   is
  #         |     margin controlled!
  #         }.margin
  #
  def margin(n=0)
    d = ((/\A.*\n\s*(.)/.match(self)) ||
        (/\A\s*(.)/.match(self)))[1]
    return '' unless d
    if n == 0
      gsub(/\n\s*\Z/,'').gsub(/^\s*[#{d}]/, '')
    else
      gsub(/\n\s*\Z/,'').gsub(/^\s*[#{d}]/, ' ' * n)
    end
  end

These methods come in very handy in avoiding the need to shove HERE docs up against the left margin, or use repetitive string concatenations. I've seen others mention them from time to time as well, so I know I'm not the only one using them.

Of course, they'd need to be converted to C, but given the size and character of the definitions, I imagine it would be a fairly straight forward translation.

(Giving credit where it is due: The first three methods were originally written by Gavin Sinclair. The later method, if I recall correctly,  by Peter Vanbroekhoven).

History

#1
Updated by ko1 (Koichi Sasada) over 3 years ago

  • Assignee set to matz (Yukihiro Matsumoto)

#2
Updated by shyouhei (Shyouhei Urabe) over 1 year ago

  • Status changed from Open to Assigned

[ruby-core:42530]#3
Updated by mame (Yusuke Endoh) 3 months ago

  • Status changed from Assigned to Rejected
I'm rejecting this feature ticket because no progress has been made for a long time. See [ruby-42391]. Sorry, I can say few comments. The use case is trivial for me. There is nothing wrong with the proposal, I think. But matz did not answer, and will not, just keeping this ticket open. I suggest you, or those who want these features, to get a fresh start; create a new ticket (with a patch if possible), and appeal to matz. -- Yusuke Endoh <mame@tsg.ne.jp>

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