On 30 March 2011 00:02, Ricky Clarkson <[email protected]> wrote:
> Could you explain how checked exceptions sidestep the type system. I
> thought they were part of it.
Sure, take my example again, cut down to the bare minimum.
Widget loadWidget(final File file) throws WidgetParseException { ... }
final List<String> paths = ImmutableList.of("/usr/home/...", ...);
final List<Widget> results = new ArrayList<Widget>();
for(String path: Paths) { results.add(loadWidget(new File(path))); }
How can I then try and load a widget for every single path in `paths`, and
capture the outcome in `results`, regardless of success or failure.
If 'checked exception' was a type, then I'd be able to create a
List<CheckedException>, and assign the results from failed loadWidget
attempts to that list.
>
> On Tue, Mar 29, 2011 at 7:50 PM, Kevin Wright <[email protected]>wrote:
>
>>
>>
>> On 29 March 2011 22:34, Reinier Zwitserloot <[email protected]> wrote:
>>
>>> On Tuesday, March 29, 2011 1:27:01 PM UTC+2, KWright wrote:
>>>>
>>>> for(String path: Paths) {
>>>> final File file = new File(path);
>>>> final Widget widget = loadWidget(file)
>>>> widgetBuilder.add(widget)
>>>> }
>>>>
>>>>
>>>
>>>> val widgets = paths map { path => loadWidget(new File(path)) }
>>>>
>>>>
>>>>
>>> One of my pet peeves is language fanboys sneaking in irrelevant
>>> complications in the language they don't like. Which you've done here. If we
>>> take scala as a cue for how language should be styled, we could just as
>>> easily write:
>>>
>>> for (String path : paths) widgetBuilder.add(loadWidget(new File(path));
>>>
>>> which is barely longer than the scala example and arguably simpler.
>>>
>>>
>> Why are you criticizing the self-proclaimed "rough first draft" and
>> totally ignoring the whole point of my message? Specifically, that using
>> checked exceptions to provide an alternate return is a flawed design,
>> because it sidesteps the type system and doesn't compose effectively - as
>> demonstrated by an example in which I apply a potentially exception-throwing
>> operation to multiple elements of a collection.
>>
>> The entire reason it's written like that is because I originally had
>> explicit exception wrapping around each line, which I subsequently removed
>> deeming it to obscure the purpose of the sample. At that point, it was
>> sufficient to demonstrate the core algorithm, and you'll even note that I
>> mentioned how necessary exception handling had been left out.
>>
>> My intent was not to make that aspect of Java syntax look artificially
>> bad, but to start with a familiar syntax before migrating to a language that
>> already has the functionality I'm advocating. I could have completed the
>> whole thing in Java, but it would have required an unwieldy amount of
>> supporting code, including either SAM types or the as-yet unfinalized Java 8
>> closure syntax.
>>
>> Perhaps you could cherry-pick a spelling mistake as well, which would then
>> *surely* demonstrate how everything I stated was completely invalid
>>
>>
>>
>>> As to the actual intent of your message - Cedric said all that needs to
>>> be said.
>>>
>>>
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>>
>>
>>
>> --
>> Kevin Wright
>>
>> gtalk / msn : [email protected]
>> <[email protected]>mail: [email protected]
>> vibe / skype: kev.lee.wright
>> quora: http://www.quora.com/Kevin-Wright
>> twitter: @thecoda
>>
>> "My point today is that, if we wish to count lines of code, we should not
>> regard them as "lines produced" but as "lines spent": the current
>> conventional wisdom is so foolish as to book that count on the wrong side of
>> the ledger" ~ Dijkstra
>>
>> --
>> You received this message because you are subscribed to the Google Groups
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>>
>
>
--
Kevin Wright
gtalk / msn : [email protected]
<[email protected]>mail: [email protected]
vibe / skype: kev.lee.wright
quora: http://www.quora.com/Kevin-Wright
twitter: @thecoda
"My point today is that, if we wish to count lines of code, we should not
regard them as "lines produced" but as "lines spent": the current
conventional wisdom is so foolish as to book that count on the wrong side of
the ledger" ~ Dijkstra
--
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Java Posse" group.
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