[racket] problem with Port Events and make-limited-input-port

THANK YOU, MATT!

-Milo


On 6/17/11, Matthew Flatt <mflatt at cs.utah.edu> wrote:
> The port created by `make-limited-input-port' didn't correctly count
> bytes that were consumed via `port-commit-peeked' (which is used by
> `read-bytes-line-evt').
>
> The bug is now fixed in the git repo, so it will be fixed in the next
> nightly build.
>
> Thanks for the report and test case!
>
> At Fri, 17 Jun 2011 17:33:56 +0100, milo arvidsson wrote:
>> (I'm using the latest build: mz-bin-i386-win32; version 5.1.1.6,
>> updated Friday, June 17 2011, 03:50 EDT)
>>
>> I've written versions of the following program using limited file,
>> string, and pipe ports with read-bytes-line-evt, read-char-evt,
>> read-line-evt, read-bytes-evt, read-string-evt, and regexp-match-evt.
>> None of the port events returned #<eof> after 4 bytes were read.
>>
>>
>> #lang racket/base
>>
>> (require racket/port)
>>
>> ;The input port is limited to 4 bytes, or just 2 lines.
>> (parameterize ((current-input-port (make-limited-input-port
>> (open-input-string "A\nB\nC\nD\n") 4)))
>>   (list
>>    (list (sync (read-bytes-line-evt (current-input-port)))
>> (file-position (current-input-port)))
>>    (list (sync (read-bytes-line-evt (current-input-port)))
>> (file-position (current-input-port)))
>>    (list (sync (read-bytes-line-evt (current-input-port)))
>> (file-position (current-input-port)))
>>    (list (sync (read-bytes-line-evt (current-input-port)))
>> (file-position (current-input-port)))))
>>
>> ;returns with: '((#"A" 2) (#"B" 4) (#"C" 6) (#"D" 8))
>>
>>
>> The following version uses 'read-bytes-line' and works as expected:
>>
>> #lang racket/base
>>
>> (require racket/port)
>>
>> (parameterize ((current-input-port (make-limited-input-port
>> (open-input-string "A\nB\nC\nD\n") 4)))
>>   (list
>>    (list (read-bytes-line) (file-position (current-input-port)))
>>    (list (read-bytes-line) (file-position (current-input-port)))
>>    (list (read-bytes-line) (file-position (current-input-port)))
>>    (list (read-bytes-line) (file-position (current-input-port)))))
>>
>> ;returns: '((#"A" 2) (#"B" 4) (#<eof> 4) (#<eof> 4))
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