Problems with making wordwrap

ruby-talk
1

hi,

i've found a great bit of code from

http://dev.rubyonrails.org/ticket/1449

that takes some text and makes it wrap at 80 lines. the only issue is that
it takes multiple line breaks (like paragraphs), and makes them into single
line breaks.

this is the code:

text.gsub( /\n/, "\n\n" ).gsub( /(.{1,80})(\s+|$)/, "\\1\n")

i've tinkered with it for a while, but i can't work out how to not have it
eat lines breaks so hungrily.

thanks for any help
luke

2

luke schrieb:

i've found a great bit of code from

http://dev.rubyonrails.org/ticket/1449

that takes some text and makes it wrap at 80 lines. the only issue is that
it takes multiple line breaks (like paragraphs), and makes them into single
line breaks.

this is the code:

text.gsub( /\n/, "\n\n" ).gsub( /(.{1,80})(\s+|$)/, "\\1\n")

i've tinkered with it for a while, but i can't work out how to not have it
eat lines breaks so hungrily.

Hi Luke,

can you tell us how you want to treat whitespace in the given text? You talked about newlines, but what should be the result in the following cases:

   "abcde\n c".wrap(5) # => "abcde\nc" or "abcde\n c"
   "a e\na".wrap(5) # => "a e\na" or "a e a"

Regards,
Pit

3

I use Text::Format for this:

def wrap(text)
   formatter = Text::Format.new
   formatter.columns = 72 # 70 + '> ' = 72
   formatter.format_style = Text::Format::LEFT_ALIGN
   formatter.first_indent = 0

   formatted =

   text.split(/\r?\n\r?\n/).each do |chunk|
     formatted << formatter.paragraphs(chunk)
   end

   return formatted.join("\n")
end

http://www.halostatue.ca/ruby/Text__Format.html

···

On Nov 19, 2005, at 10:07 PM, luke wrote:

hi,

i've found a great bit of code from

http://dev.rubyonrails.org/ticket/1449

that takes some text and makes it wrap at 80 lines. the only issue is that
it takes multiple line breaks (like paragraphs), and makes them into single
line breaks.

--
Eric Hodel - drbrain@segment7.net - http://segment7.net
FEC2 57F1 D465 EB15 5D6E 7C11 332A 551C 796C 9F04

4

luke (dot) wrote:

hi,

i've found a great bit of code from

http://dev.rubyonrails.org/ticket/1449

that takes some text and makes it wrap at 80 lines. the only issue is that
it takes multiple line breaks (like paragraphs), and makes them into single
line breaks.

this is the code:

text.gsub( /\n/, "\n\n" ).gsub( /(.{1,80})(\s+|$)/, "\\1\n")

i've tinkered with it for a while, but i can't work out how to not have it
eat lines breaks so hungrily.

thanks for any help
luke

text.gsub( /(.{1,39}[^\s])([ \t]*\n[ \t]*|[ \t]+|$)/, "\\1\n")

5

> i've found a great bit of code from
>
> http://dev.rubyonrails.org/ticket/1449
>
> that takes some text and makes it wrap at 80 lines. the only issue is

that

> it takes multiple line breaks (like paragraphs), and makes them into

single

> line breaks.
>
> this is the code:
>
> text.gsub( /\n/, "\n\n" ).gsub( /(.{1,80})(\s+|$)/, "\\1\n")
>
> i've tinkered with it for a while, but i can't work out how to not have

it

> eat lines breaks so hungrily.

Hi Luke,

can you tell us how you want to treat whitespace in the given text? You
talked about newlines, but what should be the result in the following

cases:

   "abcde\n c".wrap(5) # => "abcde\nc" or "abcde\n c"
   "a e\na".wrap(5) # => "a e\na" or "a e a"

Regards,
Pit

hi pit,

thanks for your help.

ideally how i would like it to behave given your examples, would be like:

"abcde\n c".wrap(5) # => "abcde\nc"
"a e\na".wrap(5) # => "a e\na"

does that make sense? so text would be flush with the left margin with no
white space at the beginning of new lines. but whitespace within a line
should remain intact.

thanks

luke

6

If I remember correctly, portions or the whole of Text::Format is
included with rails-core, too, but it may not be easily accessible.

-austin

···

On 11/20/05, Eric Hodel <drbrain@segment7.net> wrote:

On Nov 19, 2005, at 10:07 PM, luke wrote:
I use Text::Format for this:

--
Austin Ziegler * halostatue@gmail.com
               * Alternate: austin@halostatue.ca

7

luke schrieb:

ideally how i would like it to behave given your examples, would be like:

"abcde\n c".wrap(5) # => "abcde\nc"
"a e\na".wrap(5) # => "a e\na"

does that make sense? so text would be flush with the left margin with no
white space at the beginning of new lines. but whitespace within a line
should remain intact.

Of course it makes sense. Here's one version:

   class String
     def wrap n
       gsub(
         /
           \b # word boundary
           [ \t\r\f]* # whitespace (no newline)
           \n # newline
           [ \t\r\f]* # whitespace (no newline)
           \b # word boundary
         /x,
         " " # replaced by space
       ).gsub(
         /
           (.{1,#{n}}) # upto n characters
           ( # followed by either:
             \n # exactly one newline
             >\s+ # or other whitespace characters
           )
         /x,
         "\\1\n" # insert newline after first part
       )
     end
   end

I used extended regular expressions to show what they are doing. You can shorten them if you want.

The first gsub replaces newlines inside of paragraphs into spaces, but leaves newlines between paragraphs unchanged. The second gsub is mostly the original one, but it consumes at most one newline character (replacing it with itself). This has the effect that newlines between paragraphs are preserved.

If you still have problems or questions, feel free to ask.

Regards,
Pit

8

thanks pit,

works like a treat! nice idea of having it in the string class.

thanks a lot,
luke

"Pit Capitain" <pit@capitain.de> wrote in message
news:43807149.9050509@capitain.de...

luke schrieb:
> ideally how i would like it to behave given your examples, would be

like:

>
> "abcde\n c".wrap(5) # => "abcde\nc"
> "a e\na".wrap(5) # => "a e\na"
>
> does that make sense? so text would be flush with the left margin with

no

···

> white space at the beginning of new lines. but whitespace within a line
> should remain intact.

Of course it makes sense. Here's one version:

   class String
     def wrap n
       gsub(
         /
           \b # word boundary
           [ \t\r\f]* # whitespace (no newline)
           \n # newline
           [ \t\r\f]* # whitespace (no newline)
           \b # word boundary
         /x,
         " " # replaced by space
       ).gsub(
         /
           (.{1,#{n}}) # upto n characters
           ( # followed by either:
             \n # exactly one newline
             >\s+ # or other whitespace characters
           )
         /x,
         "\\1\n" # insert newline after first part
       )
     end
   end

I used extended regular expressions to show what they are doing. You can
shorten them if you want.

The first gsub replaces newlines inside of paragraphs into spaces, but
leaves newlines between paragraphs unchanged. The second gsub is mostly
the original one, but it consumes at most one newline character
(replacing it with itself). This has the effect that newlines between
paragraphs are preserved.

If you still have problems or questions, feel free to ask.

Regards,
Pit