Bryan R Harris wrote:
John W. Krahn wrote:
Bryan R Harris wrote:
Jenda Krynicky wrote:
Context. The <FILEHANDLE> returns a single line in scalar context and
a list of all lines in a list context. And there is no such thing as
a two-item-list context.
So in the first case the assignment to @l2r{"a","b"} provides a list
context so the very first <FILE> reads all the lines left in FILE,
the second and third return an empty list. The first two lists are
concatenated together and the first two items of the resulting list
are assigned to $l2r{"a"} and $l2r{"b"}. And the rest of the list is
forgotten. You'd have to do something like
@l2r{"a","b"} = (scalar(<FILE>), scalar(<FILE>));
or
@l2r{"a","b"} = (<FILE>.'', <FILE>.'');
to ensure that the <FILE> is evaluated in scalar context.
Which part is forcing the list context? The fact that the <FILE> is inside
parenthesis () or the @l2r{...} part?
The left hand side of the assignment determines context so the @l2r{...}
part.
That strikes me as odd... When perl goes to populate @l2r{"a","b"}, it
seems to me that it would go through this process:
- I have a slice here, so I'll loop over the slice elements
- The first is "a", so I'll pull a scalar off the list and assign it to
$l2r{"a"}
- The second is "b", so I'll pull another scalar off the list and assign it
to $l2r{"b"}
- Remaining scalars in the list are discarded
Correct, except for the loop part.
Why would $l2r{"a"} here be considered list context?
It isn't, unless it's written as ( $l2r{"a"} ), then it's a list with
one element.
What am I missing?
Hard to say? :-)
John
--
Perl isn't a toolbox, but a small machine shop where you
can special-order certain sorts of tools at low cost and
in short order. -- Larry Wall
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