From: Alex Shulgin <alex.shulgin@...>
Date: 2007-09-17T04:10:03+09:00
Subject: Newbie: what's Ruby idiom for word-by-word input?

Hi,

What is the Ruby idiom for reading input word-by-word?  In other words
-- how to process input while skipping all of the whitespace.

I would use this code in C++:

//std::istream& stream;
while (!stream.eof())
{
    std::string str;
    stream >> str;
    ...
}

Or something like this in C:

char str[100];  // please no flame on fixed buffer size :-)
while (!feof(file))
{
    fscanf("%99s", str);
    ...
}

I have tried to use Ruby's scanf("%s") but found it severely broken
(as per my task)--it discards the rest of the input up to the
newline.  I currently use the following approach, which I find ugly:

while not $stdin.eof? do
  words = $stdin.gets().scan(/[^\s]+/)
  words.each do |w|
     ...
  end
end

It takes me to write an inner loop and reads the entire string into
memory and then splits it into array of words... Duh!

My application is not in any case a time- or memory-critical, nor did
I measured to find the performance bottleneck... however, I desire for
the enlightenment. :-)

Please show me the Ruby way!


Cheers,
Alex
PS: Yes, I've searched the web, tutorials, FAQs, cookbooks, etc.
before posting this.  No luck.