Re: Issue destroying image using perl/TK

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Re^2: Issue destroying image using perl/TK by AnomalousMonk (Archbishop) on Mar 23, 2011 at 01:58 UTC
Specifically, `my $fn = @_;` initializes `$fn` with the number of elements in the `@_` array (array evaluated in scalar context). What is almost certainly wanted is `my ($fn) = @_;` or better yet `my $fn = shift;` to initialize `$fn` with the first element (index 0) of the array, Update: which, in this case, is an object reference by which an object method is called.	[reply] [d/l] [select]
Re^3: Issue destroying image using perl/TK by nikwasi (Initiate) on Mar 23, 2011 at 16:34 UTC
This did the trick. Thanks @_ is the list of incoming parameters to a subroutine. What is the significants of () around the scaler pv?	[reply]
Re^4: Issue destroying image using perl/TK by lamprecht (Friar) on Mar 23, 2011 at 19:11 UTC
`()` make the left hand side a list. Arrays return their elements when evaluated in list context. See also perldata : `Assignment is a little bit special in that it uses its left argument t +o determine the context for the right argument. Assignment to a scala +r evaluates the right-hand side in scalar context, while assignment t +o an array or hash evaluates the righthand side in list context. Assi +gnment to a list (or slice, which is just a list anyway) also evaluat +es the righthand side in list context.` [download] Cheers, Christoph	[reply] [d/l] [select]