I think I understand your question. I'm not really parsing a general
stream, but simply want to use JodaTime from a Scala combinator
parser. This is a complete combinator parser that simply wraps
JodaTime's DateTimeFormat (with my CharSeq-change) :
trait DateParsers extends RegexParsers {
def dateTime(pattern: String): Parser[DateTime] = new
Parser[DateTime] {
val dateFormat = DateTimeFormat.forPattern(pattern)
val dateParser = dateFormat.getParser
def jodaParse(text: CharSequence, offset: Int) = {
val mutableDateTime = new MutableDateTime
val newPos = dateFormat.parseInto(mutableDateTime, text, offset);
(mutableDateTime.toDateTime, newPos)
}
def apply(in: Input) = {
val source = in.source
val offset = in.offset
val start = handleWhiteSpace(source, offset)
val (dateTime, endPos) = jodaParse(source, start)
if (endPos >= 0)
Success(dateTime, in.drop(endPos - offset))
else
Failure("Failed to parse date", in.drop(start - offset))
}
}
}
I think the relevant code to your question is the Input class defined
in the Scala standard lib:
in Parsers.scala:
/** The parser input is an abstract reader of input elements, i.e.
the type of input the parsers in this component
* expect. */
type Input = Reader[Elem]
and Reader:
/** An interface for streams of values that have positions.
*
* @author Martin Odersky, Adriaan Moors
*/
abstract class Reader[+T] {
/** If this is a reader over character sequences, the underlying
char sequence
* If not, throws a <code>NoSuchMethodError</code> exception.
*/
def source: java.lang.CharSequence =
throw new NoSuchMethodError("not a char sequence reader")
def offset: Int =
throw new NoSuchMethodError("not a char sequence reader")
/** Returns the first element of the reader
*/
def first: T
/** Returns an abstract reader consisting of all elements except the first
*
* @return If <code>atEnd</code> is <code>true</code>, the result will be
* <code>this'; otherwise, it's a <code>Reader</code> containing
* more elements.
*/
def rest: Reader[T]
/** Returns an abstract reader consisting of all elements except the first
* <code>n</code> elements.
*/
def drop(n: Int): Reader[T] = {
var r: Reader[T] = this
var cnt = n
while (cnt > 0) {
r = r.rest; cnt -= 1
}
r
}
/** The position of the first element in the reader
*/
def pos: Position
/** true iff there are no more elements in this reader
*/
def atEnd: Boolean
}
As you see, there is no concrete impl. of the source method that I use
to pass to JodaTime.
There are a few different implementations of Reader. One with a
noteworthy note would be:
/** A StreamReader reads from a character sequence, typically created
as a PagedSeq
* from a java.io.Reader
*
* NOTE:
* StreamReaders do not really fulfill the new contract for readers, which
* requires a `source' CharSequence representing the full input.
* Instead source is treated line by line.
* As a consequence, regex matching cannot extend beyond a single line
* when a StreamReader are used for input.
*
* If you need to match regexes spanning several lines you should consider
* class <code>PagedSeqReader</code> instead.
*
* @author Miles Sabin
* @author Martin Odersky
*/
sealed class StreamReader(seq: PagedSeq[Char], off: Int, lnum: Int)
extends PagedSeqReader(seq, off) {
…
But in my case I'm doing a CLI and I actually just pass a String into
the framework. This is wrapped in a CharSequenceReader, which just
wraps a CharSequence. So I'm not really trying to parse general
streams, but rather just bridge the API-mismatch of the combinator
parsers and JodaTime. Am I making sense?
If theres a public API that's based on CharSequence that would be good
enough for me I think? If DateTimeParser or equivalent is part of the
public API? I just looked at the source over at
http://java.net/projects/jsr-310/sources/svn/content/trunk/jsr-310-ri/src/main/java/javax/time/calendar/format/DateTimeParser.java?rev=1339,
and it didn't look like it, but is this the right place to look?
Cheers,
Viktor
On Mon, Jul 11, 2011 at 10:42 AM, Stephen Colebourne
<scolebou...@joda.org> wrote:
> The JSR-310 public API is based on CharSequence. The private API is
> based on String.
>
> I can't see how CharSequence alone allows you to parse a stream,
> because CharSequence's methods are all about random access to a data
> structure. Perhaps you can enlighten me?
>
> Stephen
>
>
> On 11 July 2011 09:32, Viktor Hedefalk <hedef...@gmail.com> wrote:
>> Would it be possible to have this change in 310?
>>
>> Cheers,
>> Viktor
>>
>> On Sat, Feb 5, 2011 at 1:52 AM, Stephen Colebourne <scolebou...@joda.org>
>> wrote:
>>> OK.
>>>
>>> I've looked at this, and I don't feel I can make the proposed change
>>> without causing jar-hell. While there are no google references to
>>> implementations, the reality is that I would be changing the main
>>> parsing API on DateTimeFormatter, used by everyone. Methods like
>>> parseDateTime(String).
>>>
>>> Changing it from String to CharSequence is source compatible but
>>> binary incompatible (method is bound at compile time).
>>>
>>> Adding an override taking CharSequence if source compatible and binary
>>> upwards compatible, but not downward compatible (code compiled against
>>> the new version couldn't run on the old version.
>>>
>>> Thus, its my opinion that the damage far outweighs the benefits on this.
>>> Stephen
>>>
>>>
>>> On 5 February 2011 00:11, James Richardson <ja...@time4tea.net> wrote:
>>>> I Get where you are coming from. But if you did want to make a breaking
>>>> change then this would be a really appropriate place to do it. I mean if
>>>> not
>>>> on a major version number then when?
>>>> Just a thought.
>>>> James
>>>>
>>>> On 5 Feb 2011 00:03, "Stephen Colebourne" <scolebou...@joda.org> wrote:
>>>>> The problem is that the major release number is mostly about removing
>>>>> a few deprecated methods. Were I to make this change it would break
>>>>> user code, which no other change so far would cause. I don't want to
>>>>> get into the JAR-hell situation.
>>>>>
>>>>> Stephen
>>>>>
>>>>>
>>>>> On 4 February 2011 23:57, James Richardson <ja...@time4tea.net> wrote:
>>>>>> Well there is a major release version coming up... That would be an
>>>>>> appropriate time to make a breaking change, no?
>>>>>> James
>>>>>>
>>>>>> On 4 Feb 2011 23:43, "Stephen Colebourne" <scolebou...@joda.org> wrote:
>>>>>>> On 4 February 2011 23:39, Viktor Hedefalk <hedef...@gmail.com> wrote:
>>>>>>>> I guess the most obvious backwards compatability issue would be if
>>>>>>>> someone had implemented his own DateTimeParser. Hopefully that
>>>>>>>> shouldn't be too common though, it's really just an internal
>>>>>>>> interface, right?
>>>>>>>
>>>>>>> Unfortunately, no. I have encouraged users to implement this interface
>>>>>>> to solve some formatting issues. Thus I can't change it. Nor would I
>>>>>>> want to create a DateTimeParser2.
>>>>>>>
>>>>>>> Stephen
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> ------------------------------------------------------------------------------
>>>>>>> The modern datacenter depends on network connectivity to access
>>>>>>> resources
>>>>>>> and provide services. The best practices for maximizing a physical
>>>>>>> server's
>>>>>>> connectivity to a physical network are well understood - see how these
>>>>>>> rules translate into the virtual world?
>>>>>>> http://p.sf.net/sfu/oracle-sfdevnlfb
>>>>>>> _______________________________________________
>>>>>>> Joda-interest mailing list
>>>>>>> Joda-interest@lists.sourceforge.net
>>>>>>> https://lists.sourceforge.net/lists/listinfo/joda-interest
>>>>>>>
>>>>>>
>>>>>>
>>>>>> ------------------------------------------------------------------------------
>>>>>> The modern datacenter depends on network connectivity to access resources
>>>>>> and provide services. The best practices for maximizing a physical
>>>>>> server's
>>>>>> connectivity to a physical network are well understood - see how these
>>>>>> rules translate into the virtual world?
>>>>>> http://p.sf.net/sfu/oracle-sfdevnlfb
>>>>>> _______________________________________________
>>>>>> Joda-interest mailing list
>>>>>> Joda-interest@lists.sourceforge.net
>>>>>> https://lists.sourceforge.net/lists/listinfo/joda-interest
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>> ------------------------------------------------------------------------------
>>>>> The modern datacenter depends on network connectivity to access resources
>>>>> and provide services. The best practices for maximizing a physical
>>>>> server's
>>>>> connectivity to a physical network are well understood - see how these
>>>>> rules translate into the virtual world?
>>>>> http://p.sf.net/sfu/oracle-sfdevnlfb
>>>>> _______________________________________________
>>>>> Joda-interest mailing list
>>>>> Joda-interest@lists.sourceforge.net
>>>>> https://lists.sourceforge.net/lists/listinfo/joda-interest
>>>>>
>>>>
>>>> ------------------------------------------------------------------------------
>>>> The modern datacenter depends on network connectivity to access resources
>>>> and provide services. The best practices for maximizing a physical server's
>>>> connectivity to a physical network are well understood - see how these
>>>> rules translate into the virtual world?
>>>> http://p.sf.net/sfu/oracle-sfdevnlfb
>>>> _______________________________________________
>>>> Joda-interest mailing list
>>>> Joda-interest@lists.sourceforge.net
>>>> https://lists.sourceforge.net/lists/listinfo/joda-interest
>>>>
>>>>
>>>
>>> ------------------------------------------------------------------------------
>>> The modern datacenter depends on network connectivity to access resources
>>> and provide services. The best practices for maximizing a physical server's
>>> connectivity to a physical network are well understood - see how these
>>> rules translate into the virtual world?
>>> http://p.sf.net/sfu/oracle-sfdevnlfb
>>> _______________________________________________
>>> Joda-interest mailing list
>>> Joda-interest@lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/joda-interest
>>>
>>
>> ------------------------------------------------------------------------------
>> All of the data generated in your IT infrastructure is seriously valuable.
>> Why? It contains a definitive record of application performance, security
>> threats, fraudulent activity, and more. Splunk takes this data and makes
>> sense of it. IT sense. And common sense.
>> http://p.sf.net/sfu/splunk-d2d-c2
>> _______________________________________________
>> Joda-interest mailing list
>> Joda-interest@lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/joda-interest
>>
>
> ------------------------------------------------------------------------------
> All of the data generated in your IT infrastructure is seriously valuable.
> Why? It contains a definitive record of application performance, security
> threats, fraudulent activity, and more. Splunk takes this data and makes
> sense of it. IT sense. And common sense.
> http://p.sf.net/sfu/splunk-d2d-c2
> _______________________________________________
> Joda-interest mailing list
> Joda-interest@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/joda-interest
>
------------------------------------------------------------------------------
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threats, fraudulent activity, and more. Splunk takes this data and makes
sense of it. IT sense. And common sense.
http://p.sf.net/sfu/splunk-d2d-c2
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