Where is Perl's postfix `for` syntax documented?

Question

I recently came across the following code snippet

$count_stuff{$_}++ for @stuff;

It's a pretty convenient way to use a hash to count occurrences of strings in an array for example. I understand how it works, but not why it works. I can not find the documentation for this way of using for.

Why does it work? And where is the documentation?

Answer 1

It is documented in the "perlsyn" man page, under Statement Modifiers (which talks about the postfix syntax) and under Foreach Loops (which explains that "for" and "foreach" are synonyms).

Answer 2

Perl has postfix variants for many of its statements. It's just that you write the keyword after the one-statement body.

You can use if, unless, etc. in the same way.

Answer 3

According to this page it is documented here
And you should read Foreach Loops to get answer for your question.

In short, If you you understand this well:

for my $item ( @array ) { print $item }

And know syntax of for and print:

LABEL for VAR (LIST) BLOCK
print LIST

According to the doc of foreach: If VAR is omitted, $_ is set to each value.
And according to the doc of print: If LIST is omitted, prints $_

So we can reduce the example above:

for ( @array ) { print }

In the postfix form it will look like this:

print for @array;