Opened 3 weeks ago

Last modified 3 weeks ago

#1359 accepted defect

mbox-string's mbox-file->messages does not obviously match its documentation

Reported by: nxg Owned by: iraikov
Priority: major Milestone: someday
Component: unknown Version: 4.12.0
Keywords: mbox typeclass Cc:
Estimated difficulty:


The documentation in module mbox mentions a module mbox-string

[procedure] (mbox-file->messages FILENAME-OR-PORT) => MESSAGE LIST 
Given a filename or port, parses the given file as an mbox database, and returns a list of message objects. The contents of the message are represented as a string.

If, however, I use this in the way that this documentation indicates, it seems to produce errors as illustrated below.

The paragraph before the discussion of mbox-file->messages says 'The procedures in module mbox-string operate on strings.' This seems to contradict the documentation of mbox-file->messages, which claims to operate on filename-or-port, as explicitly opposed to a string.

Incidentally: I cannot deduce from the documentation how one is supposed to use any of mbox, internet-messages abnf or typeclass. Each of the first three points to typeclass for more information, but that documentation doesn't say what 'type-class-style' is (it has only one line of description) and provides an example which doesn't actually seem to use the objects it has set up. This discussion might be a little too concise to be useful. The only further information I could google about 'type-class style' was , which appears to lead us back where we started.

% csi

(c) 2008-2017, The CHICKEN Team
(c) 2000-2007, Felix L. Winkelmann
Version 4.12.0 (rev 6ea24b6)
macosx-unix-clang-x86-64 [ 64bit manyargs dload ptables ]
compiled 2017-02-19 on (Linux)

#;1> (use mbox-string)
; loading /Data/tools/chicken-4.12/lib/chicken/8/ ...
; loading /Data/tools/chicken-4.12/lib/chicken/8/ ...
;;; [...]
; loading /Data/tools/chicken-4.12/lib/chicken/8/ ...
#;2> (define text (with-input-from-file "test.mbox" read-string))
#;3> text
"From user@somewhere\nReceived: from [] ( [])\n    by (trex/5.7.12);\n    Mon, 03 Apr 2017 10:16:04 -0400\nFrom: Test User <>\nTo:\nSubject: Nothing much\nDate: Mon, 03 Apr 2017 15:16:02 +0100\n\nThis is a message for reading.\nIt's quite simple.\n\nAnd on multiple lines.\n"
#;4> (call-with-input-string text mbox-file->messages)

Error: call of non-procedure: #<unspecified>

	Call history:

	<syntax>	  (call-with-input-string text mbox-file->messages)
	<eval>	  (call-with-input-string text mbox-file->messages)	<--
#;4> (call-with-input-file "test.mbox" mbox-file->messages)

Error: call of non-procedure: #<unspecified>

	Call history:

	<syntax>	  (call-with-input-file "test.mbox" mbox-file->messages)
	<eval>	  (call-with-input-file "test.mbox" mbox-file->messages)	<--
#;4> (mbox-file->messages "test.mbox")

Error: call of non-procedure: #<unspecified>

	Call history:

	<syntax>	  (mbox-file->messages "test.mbox")
	<eval>	  (mbox-file->messages "test.mbox")	<--

Change History (2)

comment:1 Changed 3 weeks ago by iraikov

  • Owner set to iraikov
  • Status changed from new to accepted


Thanks for trying to use mbox. I think I simply never updated the documentation properly after transitioning to the typeclass interface. I will add more detailed documentation to mbox and the underlying internet-message and abnf interfaces. However, mbox-file->messages takes a file name as an argument, so that should work. I will add support for ports as well.


comment:2 Changed 3 weeks ago by nxg

Many thanks, Ivan.

I did try using mbox-file->messages with a file name, which is the last of the failing trials in the transcript. I also tried arguments like (lambda () "test.mbox"), since the error message looked a bit like it was trying to evaluate a void procedure return. But that was a stab in the dark. It's definitely processing the argument in that case, since it produces a file-not-found error if the file doesn't exist. I did look at the mbox source, but with me not understanding the other modules, I wasn't able to get much from that.

Parenthetically: The type-class approach looks very powerful, and I'd like to know more about it. I get the impression it's somewhat similar to Racket's redex as an approach (which I also would like to get the time to know more about) -- would that be correct, and if so, I wonder if this would be a possible source of documentation pointers for mbox?

Thanks for your work on the library.


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