This is probably a really silly question, but I am stumped! Let's say I have these strings:

$A:  abc.def.ghi
$B:  abc

To ask "does $A start with $B" is trivial:

$A =~ /^${B}/;

But what is the complement of this? That is, "is $B a prefix of $A?"

$B =~ /?$A?/;

Here, I am taking the fact that $B is shorter than $A, but this logic fails when $B is longer than $A. I can probably do some clunky len/substring preprocessing, but I am certain there's a more elegant regex way (isn't there always?)

Thanks in advance.

J

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