To summarize, we're discussing 3 features:
a) the ability to set the topic with a block (sub, method, etc)
b) the ability to set a default value for a parameter
c) the ability to break lexical scope
1) for $_ only
2) for any variable
Each of these features already have syntax that allows them to be used
independently:
# a) set topic
sub foo ($param is topic) { ... }
# or it's set implicitly to the first parameter
# b) default
sub foo ($param = 5) { ... }
# c) break lexical scope
$CALLER::varname
The propsals all basically boil down to bits of syntactic sugar that
combine these three features in various ways.
The fundamental question for each of the proposals is "What's the
overall gain for the language in providing syntatic sugar for this
particular combination of features?"
Allison
