Forum: Ruby Suggestions for improving code

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C5ae4f9aa0d3a9bd5376e92b322c3e50?d=identicon&s=25 Aditya Mahajan (Guest)
on 2006-03-11 18:29
(Received via mailing list)
I am trying to convert a plain text file into a tex file with
somemarkup. I have the following piece of code that does most of the
work. It works fine but does not "look good". Can someone suggest how
can I improve this code.

---------------[snip]----------------------
file = File.new(filename, 'r')
texfile = File.open(basename + ".tex", 'w')

CHAPTER = Regexp.new("CHAPTER")
SPACES  = Regexp.new("\s\s\s\s")
BLANK   = Regexp.new(/^\s*$/)

chapter = true
verse   = false
prev_line = ""

file.each_line do |line|
   if chapter && !BLANK.match(line)
     chapter = false
     texfile.puts "\\chapter{#{line.chomp}}"
   elsif CHAPTER.match(line)
     chapter = true
   elsif verse && !SPACES.match(line)
     texfile.puts '\stoplines\stopnarrower'
     texfile.puts line.chomp
     verse = false
   elsif !verse && BLANK.match(prev_line) && SPACES.match(line)
     texfile.puts '\startnarrower\startlines'
     texfile.puts line.chomp
     verse = true
   else
     texfile.puts line.chomp
   end
   prev_line = line
end
------------------[snip]--------------------

Thanks,
Aditya
2ee1a7960cc761a6e92efb5000c0f2c9?d=identicon&s=25 William James (Guest)
on 2006-03-12 08:24
(Received via mailing list)
Aditya Mahajan wrote:
> SPACES  = Regexp.new("\s\s\s\s")
>    elsif CHAPTER.match(line)
>      texfile.puts line.chomp
> http://www.eecs.umich.edu/~adityam || Ph: 7342624008
ruby -p01e'gsub(/(\n\s*\n)((?:^\s{4}.*\n)+)/,
"\\1\\startnarrower\\startlines\n\\2\\stoplines\\stopnarrower\n");
gsub(/(CHAPTER\s+)(.*)\n/,"\\chapter{\\2}\n")' in >out
C5ae4f9aa0d3a9bd5376e92b322c3e50?d=identicon&s=25 Aditya Mahajan (Guest)
on 2006-03-14 08:02
(Received via mailing list)
<--- On Mar 12, William James wrote --->

>> CHAPTER = Regexp.new("CHAPTER")
>>      texfile.puts "\\chapter{#{line.chomp}}"
>>    else
>>      texfile.puts line.chomp
>>    end
>>    prev_line = line
>> end
>> ------------------[snip]--------------------
>>
> ruby -p01e'gsub(/(\n\s*\n)((?:^\s{4}.*\n)+)/,
> "\\1\\startnarrower\\startlines\n\\2\\stoplines\\stopnarrower\n");
> gsub(/(CHAPTER\s+)(.*)\n/,"\\chapter{\\2}\n")' in >out
>
Thank you for the regex. The chapter part of your regex is better than
what I was doing, it does not correctly identify narrower region.
I think that I can tweak it a little to make it work correctly. But
what I want to know is there a better way to do this in ruby.

I am not too comfortable with coding using a regex as it can be very
difficult to maintain. Each time I have to look into the expression
and try to understand it again.

Basically the logic of the program depends on the "state" which I am
keeping track of using flags. Your code gets rid of the flags using a
two pass algorithm. What are the pros and cons. In using  a gsub, the
program needs to read the entire file before it can make any changes.
I thought that this would be memory inefficient but for a ~160 kb
file, it is almost instantaneous. Even for a 3MB file it takes less
than a second. At what file sizes should one read the file line by
line rather than entire file in a single shot?

Thanks
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