From: Joel VanderWerf <vjoel@...>
Date: 2005-12-02T17:47:57+09:00
Subject: Re: FasterCSV col separator

Kev Jackson wrote:
> Hi all,
> 
> I'm using FasterCSV and I can't seem to get the syntax correct for using 
> '|' (the pipe character) for the column separator
> 
> I have
> 
> FasterCSV.parse(csv_file, { :col_sep => "|" }) do |row|
>  p row
> end
> 
> but this fails with
> 
> invalid regular expression; there's no previous pattern, to which '+' 
> would define cardinality at 4: /\A|+/
> 
> is this a known bug?
> 
> Kev
> 
> 

Probably, the col_sep value is simply being interpolated into a regex, 
instead of first being treated with Regexp.escape. You can do the 
escaping yourself:

irb(main):001:0> /\A|+/ =~ "foo"
SyntaxError: compile error
(irb):1: invalid regular expression; there's no previous pattern, to 
which '+' would define cardinality at 4: /\A|+/
         from (irb):1
irb(main):002:0> /\A\|+/ =~ "foo"
=> nil
irb(main):003:0> /\A\|+/ =~ "|foo"
=> 0
irb(main):004:0> s = "|"
=> "|"
irb(main):005:0> Regexp.escape s
=> "\\|"

I don't know anything about FasterCSV, but maybe the author should 
consider escaping a string value for :col_sep before interpolating it in 
a regexp.

-- 
        vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407