Errata

In

$var =~ s/~[0-9]+~/~<CODE>$&</CODE>~/g

there are four ~ characters that I can't see the purpose of. In fact, if
digits are not enclosed as in ~dddd~, there will be no match.

Why not just

$var =~ s/[0-9]+/<CODE>$&</CODE>/g

This would also better tie in with the statement: "The replacement string
is <CODE>$&</CODE>" a couple of lines down.

The program does not correctly parse CSV files from Excel when an Excel cell
contains the " character. For example, consider the following Excel
worksheet:

a b c
baz 1'3"high foo
"both"

When written by Excel as a CSV one gets:

a,b,c
foo,"1'3""high",baz
"""both"""

Note that the " in the 1'3" has been doubled inside the outside pair of double
quotes. In general, each " is replaced with "", and each cell is pre- and
post-fixed by a single ".

The following program correctly parses CSV files produced by Microsoft Excel
97:

#---------------------------------------------------------------------

sub parseCSV { # (str) returns array of CSV entries (commas separated fields)
# start with Jeffrey E. F. Friedl, "Mastering Regular Expressions" method
on p 205
# modified to interpret "" as a quoted "
# Correctly parses CSV file produced by Microsoft Excel 97.
my $comma='';
my $str = $_[0];
my $preStr=$str;
my @fields = (); # initialize to null
until ( $str eq '' ) {
my $thisField='';
if( $str =~ m{^"([^",]*)"(|,(.*))$} ) {
$thisField = $1; $str=$3; $comma=$2;
} elsif ( $str =~ m{^([^",]*)(|,(.*))$} ) {
$thisField = $1; $str=$3; $comma=$2;
} elsif ( $str =~ m{^"(.*)$} ) { # there is a leading "
$str=$1;
# get all "" in remainder of this field
while( $str =~ m{^([^"]*")"(.*)$} ) {
$thisField .= $1;
$str=$2;
};
#hopefully we are at a [^,"]*", or " at end of line
if( $str =~ m{([^"]*)"(|,(.*))$} ) {
$thisField .= $1;
$str=$3;
$comma=$2;
} else {
warn "Could not find a " following >$thisField<
in
>$preStr<";
$thisField .= $str;
$str='';
};
} else {
warn "Could not match >$str< in
>$preStr<";
$str = '';
};
push( @fields, $thisField ); # add the just matched field
}
push( @fields, undef) if $comma =~ m/,$/; #account for an empty last field
return @fields;
} # end parseCSV