Question

I’m using the following line in Tcl to parse a comma-separated line of fields. Some of the fields may be quoted so they can contain comma’s:

set line {12,"34","56"}
set fresult [regsub -all {(\")([^\"]+)(\",)|([^,\"]+),} $line {{\2\4} } fields]
puts $fields
{12} {34} "56"

(It’s a bit strange that the last field is quoted instead of braced but that’s not the problem here)

However, when there is a comma in the quote, it does not work:

set line {12,"34","56,78"}
set fresult [regsub -all {(\")([^\"]+)(\",)|([^,\"]+),} $line {{\2\4} } fields]
puts $fields
{12} {34} "{56} 78"

I would expect:
{12} {34} {56,78}

Is there something wrong with my regexp or it there something tcl-ish going on?

Answer 1

One option that comes to mind is using the CSV functionality in TclLib. (No reason to reinvent the wheel unless you have to…)

http://tcllib.sourceforge.net/doc/csv.html

Docs Excerpt

::csv::split ? -alternate ? line
{sepChar ,} {delChar “} converts a
line in CSV format into a list of the
values contained in the line. The
character used to separate the values
from each other can be defined by the
caller, via sepChar, but this is
optional. The default is “,”. The
quoting character can be defined by
the caller, but this is optional. The
default is ‘”‘. If the option
-alternate is spcified a slightly different syntax is used to parse the
input. This syntax is explained below,
in the section FORMAT.