SPUG: Grep syntax

Bill Campbell bill at celestial.com
Fri Jun 15 12:55:36 PDT 2007

On Fri, Jun 15, 2007, Yitzchak Scott-Thoennes wrote:
>On Fri, June 15, 2007 9:53 am, Michael R. Wolf wrote:
>> You mentioned the 'x' operator with a scalar LHS.
>> With a list LHS, it behaves like the Python idiom you mentioned...
>> my @bcopy = (255) x @b;
>Saying it that way ("With a list LHS") makes it sound like a violation
>of two rules:
>First, that operators provide context to their operands, not vice versa.
>The operator is what decides if what's on it's left is a list or a scalar.
>(For instance, my @bcopy = @b x 1; sets @bcopy to contain a single element
>whose value is the number of elements in @b, not a copy of all the elements
>in @b.)
>Second, related to the first, parentheses don't make a list.  $x = (255)
>is no different than $x = 255.

My bad.  That was a typo.  It should have been

bcopy = [255] * len(a)

I do use parenthesis on many expressions in python and perl to
make it easier to find the end of statements with ``%'' in vi,
and to eliminate the necessity of backwhacking continuation lines
which is prone to mysterious errors if one has whitespace beyond
the ``\'' character.

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