In a testing environment, I don't want to see this warning. In a production environment, I do. Furthermore, when I want it gone, I want it gone from every instance of C<note>, without having to change something in every location. I suppose I could change all my logging calls to look like this:
{ if ( $DEBUG ) { no warnings 'uninitialized'; note("...."); } else { note("...."); } }
But that's really ugly, takes up a lot of space, is confusing, and is redundant.
Of course, no ordinary definition of a note() sub will work, since the concatenation happens before note is even touched. However, a macro could do it. It might go something like this:
macro note(Perl::Expression $expr) is parsed(/$<expr> := <Perl.arglist(:(Str))>/) { $expr.compile(:warnings(0)); }
On Mon, Apr 25, 2005 at 05:18:11AM -0600, Luke Palmer wrote: > David Storrs writes: > > sub foo { > > my ($x,$y) = @_; > > note("Entering frobnitz(). params: '$x', '$y'"); > > ... > > } > > This, of course, throws an 'uninitialized value in concatenation or > > string' warning when your test suite does this: > > is( foo(undef, undef), undef, "foo(undef, undef) gives undef" ); > > How would I best solve this problem in Perl6?
> Of course, no ordinary definition of a note() sub will work, since the > concatenation happens before note is even touched.
Exactly; that's why I asked "how would I solve this", instead of "how would I write note()".
> However, a macro could do it. It might go something like this:
Cool. But that seems to turn off all warnings during the compilation of the expression--I only want to get rid of the (expected) 'uninitialized' warning. Will there be a way to do finer-grained control?
> Cool. But that seems to turn off all warnings during the compilation > of the expression--I only want to get rid of the (expected) > 'uninitialized' warning. Will there be a way to do finer-grained > control?
> In a testing environment, I don't want to see this warning.
> In a > production environment, I do. Furthermore, when I want it gone, I > want it gone from every instance of C<note>, without having to change > something in every location. I suppose I could change all my logging > calls to look like this:
> { > if ( $DEBUG ) { no warnings 'uninitialized'; note("...."); } > else { note("...."); } > }
> But that's really ugly, takes up a lot of space, is confusing, and is > redundant.
> How would I best solve this problem in Perl6?
Write an appropriate macro:
warns(is( foo(undef, undef), undef, "foo(undef, undef) gives undef"), "uninitialized value in concatenation or string");
That way you get to ensure that the warning gets thrown correctly if undef is passed, but you don't get the warning mucking up your test output.
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