[Melbourne-pm] basic regex - char array vs "pipe brackets"

[Christopher Short]

Hmm ... I've been proven wrong ... (again!)
I saw this regex in someone else's code (to check validity of an id field)
/^(\w|\@|\.|\-)+$/

and decided that it wouldn't work properly, that what they'd meant was
the character array
/^[\w\@\.\-]+$/

Luckily I chucked it into Regex Coach and found both of them worked
just as well.
Thing is, when I look at
/^(\w|\@|\.|\-)+$/
I automatically assume it will look for repeated occurences of the
first character, as this would:
/^(\w|\@|\.|\-)\1*$/

How should I remember that it doesn't work that way? That the "memory
brackets" only get used where \1 , $1 etc are specifically mentioned?

Turns out the long-term perl developer who wrote that code always uses
"pipe brackets" instead of character arrays.
Do they really function identically?

Christopher