Re: Parameterized String Externalization
On 2009-04-30 16:33:19 -0400, Mark Space <markspace@sbc.global.net> said:
Owen Jacobson wrote:
(I habitually use positional specifiers -- %1$d, %2$s, etc -- in format
strings to permit localization to re-order the placeholders. Using
non-positional format specifiers means that the placeholders MUST
appear in the same order as the parameters to String.format. I'd love
it if there were named placeholders, as with Python's format
specifiers, but without a syntax for named parameters it'd be painfully
verbose to implement.)
Interesting. How does this help in Python? It seems to me that even
with named parameters, you still have to rejigger the order somehow.
This should be the same as a method call with parameters in a different
order, I think.
Not trying to start a language flame war, just curious if such a thing
really could be implemented in Java.
In python, you have the following construction:
"foo: %(foo)s, bar: %(bar)d" % {'foo': 'hello', 'bar': 667}
which evaluates to "foo: hello, bar: 667". The placeholders can be
reordered however you like; as they contain a name, they're substituted
for only the named entry in the right-hand argument to %.
Doing something similar in Java would require a terse Map syntax. The
closest I've ever come up with,
new HashMap<String, Object> () {{
put ("foo": "hello");
put ("bar": 667);
}}
plays havoc on serialization (if you care about that) and takes up many
many more characters to say almost the same thing, which makes it hard
to use inline in a string-formatting context. The other option would be
a method like format(String, Object...), with a documentation note to
the effect that the varargs parameter is expecting alternating names
and values:
format("foo: %(foo)s, bar: %(bar)d", "foo", "hello", "bar" 667);
and that's, well, wrong.
Cheers,
-o