From: RichardOnRails <RichardDummyMailbox58407@...>
Date: 2011-01-18T05:40:21+09:00
Subject: Re: A tad of meta-programming needed

On Jan 17, 7:38 am, botp <botp...@gmail.com> wrote:
> On Mon, Jan 17, 2011 at 2:05 PM, Josh Cheek <josh.ch...@gmail.com> wrote:
> > On Sun, Jan 16, 2011 at 11:30 PM, RichardOnRails <
> > The matchdata object implements the same inteface as a hash. If that is all
> > you need, on 1.9 you could just name the capture groups, then use the
> > MatchData object and not have to do any assignment/creation at all.
> > (Assuming this data is based on the pastie you posted earlier, this code
> > would work)
> > RUBY_VERSION # => "1.9.2"
> > line = "Apple 1.1234 1/2/3 4/5/6 $1,234.56 $7 ($5)"
> > regex = /^(?<name>       .+                       )\s
> >          (?<n_shares>   \d+\.\d{4}               )\s+
> >          (?<opened_MDY> \d\d?\/  \d\d?\/  \d\d?  )\s+
> >          (?<closed_MDY> \d\d?\/  \d\d?\/  \d\d?  )\s+
> >          (?<proceeds>   [\$\d,\.]+               )\s+
> >          (?<cost>       [\$\d,\.]+               )\s+
> >          (?<gain_Loss>  [\(\)\$,\d \.]+          )\s*
> >        $/x
> > result = regex.match(line)
>
> or for older reg engines, they can do parallel assignments w array or splat
>
> something like
>
> _,:name,:n_shares,:opened = regex.match(line).to_a
>
> or
>
> _,:name,:n_shares,:opened = *regex.match(line)
>
> best regards -botp

Hi botp,

Thanks for that very interesting approach.  It's beautifully
succinct.  I tried running it on my WinXP-Pro/SP3 machine running Ruby
1.8.6 and was unsuccessful in running your example.  I probably
overlooked some detail, for which I apologize.

Here's what I ran:
_, :name, :shares, :opened_MDY, :closed_MDY, :proceeds, :cost, :gainLoss
= regex.match(line).to_a

I got:
ProcessTaxData.rb:116: syntax error, unexpected ',', expecting tCOLON2
or '[' or '.'
	
_, :name, :shares, :opened_MDY, :closed_MDY, :proceeds, :cost, :gainLoss
= regex.match(line).to_a
	         ^

I ran this in SciTE 1.74, where the output is rendered in monotype
font, I believe. So SciTE actually displayed the "^" under the "m" of
the ":name" symbol, despite the rendering above.

While the symbols didn't work, using local variables did in this
simple test:
string = "abc  123x45"
regex = /(\w+)\s*(\d+)/

puts "Test 1"
_, @x, @y = regex.match(string).to_a
puts @x, @y # => abc and 123 on successive lines

Do you have a working example with symbols you could provide me?  And
what version of Ruby ran it?

Again, thanks for helping with my Ruby education.

Best wishes,
Richard