Given the attached test.csv file, the following program
loops forever (can't even ^c):

import re

orig = open('test.csv')

file_contents = orig.read()
orig.close()

find_line = re.compile(r'^(".*")?(,(".*")?)*\n')
search_result = find_line.search(file_contents)
print search_result.span()

The corresponding tcl program works correctly:

set orig [open test.csv r]

set file_contents [read $orig]
close $orig

regexp -indices {^(".*")?(,(".*")?)*\n} $file_contents
\ indices
puts "Indices were $indices"

Both tests were run on a TP G41 running Gentoo Linux.