Favorite idiom for "keep doing this until it returns nil/fal

Ruby
1

I want to keep running gsub! on a string until it returns nil. How do
you prefer to do this?

true while str.gsub!( … )

while str.gsub!( … ); end

begin
done = !str.gsub!( … )
end until done

begin
made_replacement = str.gsub!( … )
end while made_replacement

…some other way?

2

I would use:
while str.gsub!( … ); end

“block … while” is a ‘regretted’ feature
(http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/6768).

2007/9/24, Phrogz [email protected]:

3

“block … while” is a ‘regretted’ feature
(http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-core/6768).
Sorry, I meant
“begin … end while” is a ‘regretted’ feature

Gaspard

4

On Sep 24, 2:27 pm, Phrogz [email protected] wrote:

begin
made_replacement = str.gsub!( … )
end while made_replacement

…some other way?

Proper devotion to symmetry leads us to the knowledge that the
sacred bang character must always be paired.

until !str.gsub!( … ); end

5

On Sep 24, 2007, at 3:30 PM, Phrogz wrote:

begin
made_replacement = str.gsub!( … )
end while made_replacement

…some other way?

loop { break if str.gsub!(…).nil? }

because it clearly expresses the idea of “keep running gsub! on a
string until it returns nil”.

Regards, Morton

6

Hi –

On Wed, 26 Sep 2007, William J. wrote:

On Sep 24, 2:27 pm, Phrogz [email protected] wrote:

I want to keep running gsub! on a string until it returns nil. How do
you prefer to do this?

true while str.gsub!( … )

Less prolix:

0 while str.gsub!( … )

I wouldn’t worry; the first version isn’t exactly “War and Peace” :slight_smile:
I dislike the throwaway nature of both of them anyway.

David

7

On 9/24/07, Phrogz [email protected] wrote:

…some other way?

a = “bccccce”
begin
callcc{|@a|}
a.gsub!(/bc/,“cb”) or raise nil
@a.call
rescue
puts a
end

What else, threads maybe :wink:
Robert

8

On Sep 24, 2007, at 1:30 PM, Phrogz wrote:

begin
made_replacement = str.gsub!( … )
end while made_replacement

…some other way?

loop{ str.gsub!(re, repl) or break }

a @ http://drawohara.com/

9

On Sep 24, 2:27 pm, Phrogz [email protected] wrote:

I want to keep running gsub! on a string until it returns nil. How do
you prefer to do this?

true while str.gsub!( … )

Less prolix:

0 while str.gsub!( … )

10

On Sep 26, 4:18 am, “David A. Black” [email protected] wrote:

I wouldn’t worry; the first version isn’t exactly “War and Peace”

More terse:

“War & Peace”

11

On Thu, 27 Sep 2007 02:00:15 +0900, William J. [email protected]
wrote:

On Sep 26, 4:18 am, “David A. Black” [email protected] wrote:

I wouldn’t worry; the first version isn’t exactly “War and Peace”

More terse:

“War & Peace”

nil while war && peace

-mental

12

Phrogz wrote:

begin
made_replacement = str.gsub!( … )
end while made_replacement

…some other way?

Having been gotten accustomed to the

while (!expr) {
do_this();
}

way of writing things, I would probably use this in ruby:

until str.gsub!( … ) end

Generally, I write what ever I feel works when I am testing. The try to
refine
it into as clear and concise a manor as I can before I finish the
prototype.

TerryP.