HaloO,
Tim Bunce wrote:
On Sun, Jan 11, 2009 at 04:41:12PM -0800, Ovid wrote:
I really don't think this is a bug, but it did confuse the heck out of me at
first. This *is* expected behavior due to how {} is interpolated in strings,
yes?
$ perl6 -e 'my $foo = "foo";say "<" ~ $foo ~ ">"'
<foo>
$ perl6 -e 'my $foo = "foo";say "{" ~ $foo ~ "}"'
~ foo ~
I presume string interpolation is, er, "set-up", at compile-time.
So it only happened here because "{" ~ $foo ~ "}" was rewritten to
"{$foo}" at compile-time. And if "{" and "}" were replaced with
variables, for example, then the interpolation wouldn't have happened.
Right?
The point is that the code that is interpolated is just the
string " ~ $foo ~ " which is interpolated when the closure runs.
That is there are two nested interpolations! Note that you can't
use "{" to initialize a variable because it either ends in a syntax
error or as in the given example swallows some code into a string.
This works as you intent:
my $left = '{';
my $right = '}';
my $foo = "foo"; # no danger with interpolation
say $left ~ $foo ~ $right;
That is in the example from Ovid there are *no* concatenations!
Regards, TSa.
--
"The unavoidable price of reliability is simplicity" -- C.A.R. Hoare
"Simplicity does not precede complexity, but follows it." -- A.J. Perlis
1 + 2 + 3 + 4 + ... = -1/12 -- Srinivasa Ramanujan
