$text2 = 'foo|abc-./|foo ';

# $text2 =~ s%(foo|\w+)([//.-]+)(.*)%$1 :i: $2 :i: $3%g;

# output is:  ++foo|abc :i: -./ :i: |foo ++
# captures the hyphen, dot and slash in $2 with ONLY the fwd_slash escaped 
# and capturs "|foo " in $3  

# $text2 =~ s%([\w|]+)([.-]+)(.*)%__$1_:_$2_:_$3__ : second variation%g;

# output is:  ++__foo|abc_:_-._:_/|foo __ : second variation++
# hyphen, dot still captured in $2 with no escaping at all inside the class

$text2 =~ s%([\w|]+)([.-]+/)(.*)%$1:$2:$3 : third variation%g;

# output is: ++foo|abc:-./:|foo  : third variation++
# Moved the fw_slash (unescaped, using % as delimiters) into the second capture 
# expression... and fw_slash turns up correctly in $2

print "\t++$text2++\n";