I was taught that for structure was like this: (starting value, ending value, increment). But I infer from your response that it must be: (starting value, continue while this is true, increment)?

Won't hurt you to read the docs...

What's wrong:

• The first expression has nothing to do with a "starting value". (Starting value of what??? It's not like C-style loops have counters.)

• The last expression has nothing to do with an "increment". (Incrementing what??? It's not like C-style loops have counters.)

What it really means

• The first expression (if specified) is evaluated unconditionally before the loop is started.

• The second expression is evaluated at the start of every loop pass (incl the first). If an expression is specified and it evaluates to something false, the look exits.

• The third expression (if specified) is evaluated at the end of every loop pass (even if next is called).

A common usage:

for (my $i = 0; $i < $n; ++$i) {
   ...
}
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The above is equivalent to the following, except $i is scoped to the loop.

my $i = 0;
while ($i < $n) {
   ...
} continue {
   ++$i
}
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