On Wed, Oct 11, 2006 at 05:55:45PM -0700, Jonathan Lang wrote:
: While I agree with most of the changes made to the s[]... notation,
: there's one oddity that I just spotted:
:
: S05 says:
: >This is not a normal assigment, since the right side is
: >evaluated each time the substitution matches (much like the
: >pseudo-assignment to declarators can happen at strange times).
: >It is therefore treated as a "thunk", that is, as if it has
: >implicit curlies around it. In fact, it makes no sense at all
: >to say
: >
: > s[pattern] = { doit }
: >
: >because that would try to substitute a closure into the string.
:
: So I can't say something like
:
: s[(\d+)!] = { my $num = 1; $num *= $_ for 0..$0; return $num; }
s[(\d+)!] = "{ my $num = 1; $num *= $_ for 0..$0; return $num; }"
s[(\d+)!] = { my $num = 1; $num *= $_ for 0..$0; return $num; }.()
s[(\d+)!] = do { my $num = 1; $num *= $_ for 0..$0; return $num; }
: or
:
: s:s:g[(\w+): (\d+) dB] =
: @() -> $name, $num {
: $num = exp($num/10, 10);
: say "$name has excessive wattage: $num Watts" if $num > 1000000;
:
: "$name: $num Watts";
: }
s:s:g[(\w+): (\d+) dB] = do
given @() -> [$name, $num] {
$num = exp($num/10, 10);
say "$name has excessive wattage: $num Watts" if $num > 1000000;
"$name: $num Watts";
}
: or
:
: s:s:g[<,> (\w+): (.+) <,>] = @() -> $key, $val { $key => $val }
s:s:g[<,> (\w+): (.+) <,>] = -> $key, $val { $key => $val }.(@())
s:s:g[<,> (\w+): (.+) <,>] = do for @().each -> $key, $val { $key => $val }
: ? That seems like a pretty significant limitation. Could closures be
: an exception to the "implicit curlies" rule? That is: if you supply
: your own closure on the right, the substitution algorithm accepts it
: as is; if you supply anything else, it gets wrapped in a closure as
: described.
Could do that too (and there's even precedent with attribute defaults),
but outlawing it (at least for now) keeps people from cargo culting
P5's s{foo}{bar} into P6's s{foo}={bar}.
Larry
