@synindex fn cp
@synindex vr cp
@synindex pg cp
-@dircategory Emacs
-@direntry
-* Emacs MIME: (emacs-mime). The MIME de/composition library.
-@end direntry
-@iftex
-@finalout
-@end iftex
-@setchapternewpage odd
-
-@ifnottex
+@copying
This file documents the Emacs MIME interface functionality.
-Copyright (C) 1998, 1999, 2000, 2001, 2002 Free Software Foundation, Inc.
+Copyright @copyright{} 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
+2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+@quotation
Permission is granted to copy, distribute and/or modify this document
-under the terms of the GNU Free Documentation License, Version 1.1 or
+under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
-Invariant Sections, with the Front-Cover texts being ``A GNU
-Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
-license is included in the section entitled ``GNU Free Documentation
-License'' in the Emacs manual.
-
-(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
-this GNU Manual, like GNU software. Copies published by the Free
-Software Foundation raise funds for GNU development.''
-
-This document is part of a collection distributed under the GNU Free
-Documentation License. If you want to distribute this document
-separately from the collection, you can do so by adding a copy of the
-license to the document, as described in section 6 of the license.
-@end ifnottex
+Invariant Sections, with the Front-Cover texts being ``A GNU Manual'',
+and with the Back-Cover Texts as in (a) below. A copy of the license
+is included in the section entitled ``GNU Free Documentation License''.
+
+(a) The FSF's Back-Cover Text is: ``You have the freedom to copy and
+modify this GNU manual. Buying copies from the FSF supports it in
+developing GNU and promoting software freedom.''
+@end quotation
+@end copying
+
+@c Node ``Interface Functions'' uses Latin-1 characters
+@documentencoding ISO-8859-1
-@tex
+@dircategory Emacs
+@direntry
+* Emacs MIME: (emacs-mime). Emacs MIME de/composition library.
+@end direntry
+@iftex
+@finalout
+@end iftex
+@setchapternewpage odd
@titlepage
@title Emacs MIME Manual
@author by Lars Magne Ingebrigtsen
@page
-
@vskip 0pt plus 1filll
-Copyright @copyright{} 1998, 1999, 2000 Free Software Foundation, Inc.
-
-Permission is granted to copy, distribute and/or modify this document
-under the terms of the GNU Free Documentation License, Version 1.1 or
-any later version published by the Free Software Foundation; with the
-Invariant Sections being none, with the Front-Cover texts being ``A GNU
-Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
-license is included in the section entitled ``GNU Free Documentation
-License'' in the Emacs manual.
-
-(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
-this GNU Manual, like GNU software. Copies published by the Free
-Software Foundation raise funds for GNU development.''
-
-This document is part of a collection distributed under the GNU Free
-Documentation License. If you want to distribute this document
-separately from the collection, you can do so by adding a copy of the
-license to the document, as described in section 6 of the license.
+@insertcopying
@end titlepage
-@page
-@end tex
+@contents
@node Top
@top Emacs MIME
This manual documents the libraries used to compose and display
-@sc{mime} messages.
+@acronym{MIME} messages.
-This is not a manual meant for users; it's a manual directed at people
-who want to write functions and commands that manipulate @sc{mime}
-elements.
+This manual is directed at users who want to modify the behavior of
+the @acronym{MIME} encoding/decoding process or want a more detailed
+picture of how the Emacs @acronym{MIME} library works, and people who want
+to write functions and commands that manipulate @acronym{MIME} elements.
-@sc{mime} is short for @dfn{Multipurpose Internet Mail Extensions}.
+@acronym{MIME} is short for @dfn{Multipurpose Internet Mail Extensions}.
This standard is documented in a number of RFCs; mainly RFC2045 (Format
of Internet Message Bodies), RFC2046 (Media Types), RFC2047 (Message
-Header Extensions for Non-ASCII Text), RFC2048 (Registration
+Header Extensions for Non-@acronym{ASCII} Text), RFC2048 (Registration
Procedures), RFC2049 (Conformance Criteria and Examples). It is highly
-recommended that anyone who intends writing @sc{mime}-compliant software
+recommended that anyone who intends writing @acronym{MIME}-compliant software
read at least RFC2045 and RFC2047.
+@ifnottex
+@insertcopying
+@end ifnottex
+
@menu
+* Decoding and Viewing:: A framework for decoding and viewing.
+* Composing:: @acronym{MML}; a language for describing @acronym{MIME} parts.
* Interface Functions:: An abstraction over the basic functions.
* Basic Functions:: Utility and basic parsing functions.
-* Decoding and Viewing:: A framework for decoding and viewing.
-* Composing:: MML; a language for describing MIME parts.
* Standards:: A summary of RFCs and working documents used.
+* GNU Free Documentation License:: The license for this documentation.
* Index:: Function and variable index.
@end menu
-@node Interface Functions
-@chapter Interface Functions
-@cindex interface functions
-@cindex mail-parse
+@node Decoding and Viewing
+@chapter Decoding and Viewing
-The @code{mail-parse} library is an abstraction over the actual
-low-level libraries that are described in the next chapter.
+This chapter deals with decoding and viewing @acronym{MIME} messages on a
+higher level.
-Standards change, and so programs have to change to fit in the new
-mold. For instance, RFC2045 describes a syntax for the
-@code{Content-Type} header that only allows ASCII characters in the
-parameter list. RFC2231 expands on RFC2045 syntax to provide a scheme
-for continuation headers and non-ASCII characters.
+The main idea is to first analyze a @acronym{MIME} article, and then allow
+other programs to do things based on the list of @dfn{handles} that are
+returned as a result of this analysis.
-The traditional way to deal with this is just to update the library
-functions to parse the new syntax. However, this is sometimes the wrong
-thing to do. In some instances it may be vital to be able to understand
-both the old syntax as well as the new syntax, and if there is only one
-library, one must choose between the old version of the library and the
-new version of the library.
+@menu
+* Dissection:: Analyzing a @acronym{MIME} message.
+* Non-MIME:: Analyzing a non-@acronym{MIME} message.
+* Handles:: Handle manipulations.
+* Display:: Displaying handles.
+* Display Customization:: Variables that affect display.
+* Files and Directories:: Saving and naming attachments.
+* New Viewers:: How to write your own viewers.
+@end menu
-The Emacs MIME library takes a different tack. It defines a series of
-low-level libraries (@file{rfc2047.el}, @file{rfc2231.el} and so on)
-that parses strictly according to the corresponding standard. However,
-normal programs would not use the functions provided by these libraries
-directly, but instead use the functions provided by the
-@code{mail-parse} library. The functions in this library are just
-aliases to the corresponding functions in the latest low-level
-libraries. Using this scheme, programs get a consistent interface they
-can use, and library developers are free to create write code that
-handles new standards.
-The following functions are defined by this library:
+@node Dissection
+@section Dissection
-@table @code
-@item mail-header-parse-content-type
-@findex mail-header-parse-content-type
-Parse a @code{Content-Type} header and return a list on the following
-format:
+The @code{mm-dissect-buffer} is the function responsible for dissecting
+a @acronym{MIME} article. If given a multipart message, it will recursively
+descend the message, following the structure, and return a tree of
+@acronym{MIME} handles that describes the structure of the message.
+
+@node Non-MIME
+@section Non-MIME
+@vindex mm-uu-configure-list
+
+Gnus also understands some non-@acronym{MIME} attachments, such as
+postscript, uuencode, binhex, yenc, shar, forward, gnatsweb, pgp,
+diff. Each of these features can be disabled by add an item into
+@code{mm-uu-configure-list}. For example,
@lisp
-("type/subtype"
- (attribute1 . value1)
- (attribute2 . value2)
- ...)
+(require 'mm-uu)
+(add-to-list 'mm-uu-configure-list '(pgp-signed . disabled))
@end lisp
-Here's an example:
-
-@example
-(mail-header-parse-content-type
- "image/gif; name=\"b980912.gif\"")
-@result{} ("image/gif" (name . "b980912.gif"))
-@end example
+@table @code
+@item postscript
+@findex postscript
+PostScript file.
-@item mail-header-parse-content-disposition
-@findex mail-header-parse-content-disposition
-Parse a @code{Content-Disposition} header and return a list on the same
-format as the function above.
+@item uu
+@findex uu
+Uuencoded file.
-@item mail-content-type-get
-@findex mail-content-type-get
-Takes two parameters---a list on the format above, and an attribute.
-Returns the value of the attribute.
+@item binhex
+@findex binhex
+Binhex encoded file.
-@example
-(mail-content-type-get
- '("image/gif" (name . "b980912.gif")) 'name)
-@result{} "b980912.gif"
-@end example
+@item yenc
+@findex yenc
+Yenc encoded file.
-@item mail-header-encode-parameter
-@findex mail-header-encode-parameter
-Takes a parameter string and returns an encoded version of the string.
-This is used for parameters in headers like @code{Content-Type} and
-@code{Content-Disposition}.
+@item shar
+@findex shar
+Shar archive file.
-@item mail-header-remove-comments
-@findex mail-header-remove-comments
-Return a comment-free version of a header.
+@item forward
+@findex forward
+Non-@acronym{MIME} forwarded message.
-@example
-(mail-header-remove-comments
- "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
-@result{} "Gnus/5.070027 "
-@end example
+@item gnatsweb
+@findex gnatsweb
+Gnatsweb attachment.
-@item mail-header-remove-whitespace
-@findex mail-header-remove-whitespace
-Remove linear white space from a header. Space inside quoted strings
-and comments is preserved.
+@item pgp-signed
+@findex pgp-signed
+@acronym{PGP} signed clear text.
-@example
-(mail-header-remove-whitespace
- "image/gif; name=\"Name with spaces\"")
-@result{} "image/gif;name=\"Name with spaces\""
-@end example
+@item pgp-encrypted
+@findex pgp-encrypted
+@acronym{PGP} encrypted clear text.
-@item mail-header-get-comment
-@findex mail-header-get-comment
-Return the last comment in a header.
+@item pgp-key
+@findex pgp-key
+@acronym{PGP} public keys.
-@example
-(mail-header-get-comment
- "Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
-@result{} "Finnish Landrace"
-@end example
+@item emacs-sources
+@findex emacs-sources
+@vindex mm-uu-emacs-sources-regexp
+Emacs source code. This item works only in the groups matching
+@code{mm-uu-emacs-sources-regexp}.
-@item mail-header-parse-address
-@findex mail-header-parse-address
-Parse an address and return a list containing the mailbox and the
-plaintext name.
+@item diff
+@vindex diff
+@vindex mm-uu-diff-groups-regexp
+Patches. This is intended for groups where diffs of committed files
+are automatically sent to. It only works in groups matching
+@code{mm-uu-diff-groups-regexp}.
-@example
-(mail-header-parse-address
- "Hrvoje Niksic <hniksic@@srce.hr>")
-@result{} ("hniksic@@srce.hr" . "Hrvoje Niksic")
-@end example
+@item verbatim-marks
+@cindex verbatim-marks
+Slrn-style verbatim marks.
-@item mail-header-parse-addresses
-@findex mail-header-parse-addresses
-Parse a string with list of addresses and return a list of elements like
-the one described above.
+@item LaTeX
+@cindex LaTeX
+LaTeX documents. It only works in groups matching
+@code{mm-uu-tex-groups-regexp}.
-@example
-(mail-header-parse-addresses
- "Hrvoje Niksic <hniksic@@srce.hr>, Steinar Bang <sb@@metis.no>")
-@result{} (("hniksic@@srce.hr" . "Hrvoje Niksic")
- ("sb@@metis.no" . "Steinar Bang"))
-@end example
+@end table
-@item mail-header-parse-date
-@findex mail-header-parse-date
-Parse a date string and return an Emacs time structure.
+@cindex text/x-verbatim
+@c Is @vindex suitable for a face?
+@vindex mm-uu-extract
+Some inlined non-@acronym{MIME} attachments are displayed using the face
+@code{mm-uu-extract}. By default, no @acronym{MIME} button for these
+parts is displayed. You can force displaying a button using @kbd{K b}
+(@code{gnus-summary-display-buttonized}) or add @code{text/x-verbatim}
+to @code{gnus-buttonized-mime-types}, @xref{MIME Commands, ,MIME
+Commands, gnus, Gnus Manual}.
-@item mail-narrow-to-head
-@findex mail-narrow-to-head
-Narrow the buffer to the header section of the buffer. Point is placed
-at the beginning of the narrowed buffer.
+@node Handles
+@section Handles
-@item mail-header-narrow-to-field
-@findex mail-header-narrow-to-field
-Narrow the buffer to the header under point. Understands continuation
-headers.
+A @acronym{MIME} handle is a list that fully describes a @acronym{MIME}
+component.
-@item mail-header-fold-field
-@findex mail-header-fold-field
-Fold the header under point.
+The following macros can be used to access elements in a handle:
-@item mail-header-unfold-field
-@findex mail-header-unfold-field
-Unfold the header under point.
+@table @code
+@item mm-handle-buffer
+@findex mm-handle-buffer
+Return the buffer that holds the contents of the undecoded @acronym{MIME}
+part.
-@item mail-header-field-value
-@findex mail-header-field-value
-Return the value of the field under point.
+@item mm-handle-type
+@findex mm-handle-type
+Return the parsed @code{Content-Type} of the part.
-@item mail-encode-encoded-word-region
-@findex mail-encode-encoded-word-region
-Encode the non-ASCII words in the region. For instance,
-@samp{Naïve} is encoded as @samp{=?iso-8859-1?q?Na=EFve?=}.
+@item mm-handle-encoding
+@findex mm-handle-encoding
+Return the @code{Content-Transfer-Encoding} of the part.
-@item mail-encode-encoded-word-buffer
-@findex mail-encode-encoded-word-buffer
-Encode the non-ASCII words in the current buffer. This function is
-meant to be called narrowed to the headers of a message.
+@item mm-handle-undisplayer
+@findex mm-handle-undisplayer
+Return the object that can be used to remove the displayed part (if it
+has been displayed).
-@item mail-encode-encoded-word-string
-@findex mail-encode-encoded-word-string
-Encode the words that need encoding in a string, and return the result.
+@item mm-handle-set-undisplayer
+@findex mm-handle-set-undisplayer
+Set the undisplayer object.
-@example
-(mail-encode-encoded-word-string
- "This is naïve, baby")
-@result{} "This is =?iso-8859-1?q?na=EFve,?= baby"
-@end example
+@item mm-handle-disposition
+@findex mm-handle-disposition
+Return the parsed @code{Content-Disposition} of the part.
-@item mail-decode-encoded-word-region
-@findex mail-decode-encoded-word-region
-Decode the encoded words in the region.
+@item mm-get-content-id
+Returns the handle(s) referred to by @code{Content-ID}.
-@item mail-decode-encoded-word-string
-@findex mail-decode-encoded-word-string
-Decode the encoded words in the string and return the result.
+@end table
-@example
-(mail-decode-encoded-word-string
- "This is =?iso-8859-1?q?na=EFve,?= baby")
-@result{} "This is naïve, baby"
-@end example
-@end table
+@node Display
+@section Display
-Currently, @code{mail-parse} is an abstraction over @code{ietf-drums},
-@code{rfc2047}, @code{rfc2045} and @code{rfc2231}. These are documented
-in the subsequent sections.
+Functions for displaying, removing and saving.
+@table @code
+@item mm-display-part
+@findex mm-display-part
+Display the part.
+@item mm-remove-part
+@findex mm-remove-part
+Remove the part (if it has been displayed).
-@node Basic Functions
-@chapter Basic Functions
+@item mm-inlinable-p
+@findex mm-inlinable-p
+Say whether a @acronym{MIME} type can be displayed inline.
-This chapter describes the basic, ground-level functions for parsing and
-handling. Covered here is parsing @code{From} lines, removing comments
-from header lines, decoding encoded words, parsing date headers and so
-on. High-level functionality is dealt with in the next chapter
-(@pxref{Decoding and Viewing}).
-
-@menu
-* rfc2045:: Encoding @code{Content-Type} headers.
-* rfc2231:: Parsing @code{Content-Type} headers.
-* ietf-drums:: Handling mail headers defined by RFC822bis.
-* rfc2047:: En/decoding encoded words in headers.
-* time-date:: Functions for parsing dates and manipulating time.
-* qp:: Quoted-Printable en/decoding.
-* base64:: Base64 en/decoding.
-* binhex:: Binhex decoding.
-* uudecode:: Uuencode decoding.
-* rfc1843:: Decoding HZ-encoded text.
-* mailcap:: How parts are displayed is specified by the @file{.mailcap} file
-@end menu
+@item mm-automatic-display-p
+@findex mm-automatic-display-p
+Say whether a @acronym{MIME} type should be displayed automatically.
+@item mm-destroy-part
+@findex mm-destroy-part
+Free all resources occupied by a part.
-@node rfc2045
-@section rfc2045
+@item mm-save-part
+@findex mm-save-part
+Offer to save the part in a file.
-RFC2045 is the ``main'' @sc{mime} document, and as such, one would
-imagine that there would be a lot to implement. But there isn't, since
-most of the implementation details are delegated to the subsequent
-RFCs.
+@item mm-pipe-part
+@findex mm-pipe-part
+Offer to pipe the part to some process.
-So @file{rfc2045.el} has only a single function:
+@item mm-interactively-view-part
+@findex mm-interactively-view-part
+Prompt for a mailcap method to use to view the part.
-@table @code
-@item rfc2045-encode-string
-@findex rfc2045-encode-string
-Takes a parameter and a value and returns a @samp{PARAM=VALUE} string.
-@var{value} will be quoted if there are non-safe characters in it.
@end table
-@node rfc2231
-@section rfc2231
+@node Display Customization
+@section Display Customization
-RFC2231 defines a syntax for the @code{Content-Type} and
-@code{Content-Disposition} headers. Its snappy name is @dfn{MIME
-Parameter Value and Encoded Word Extensions: Character Sets, Languages,
-and Continuations}.
+@table @code
-In short, these headers look something like this:
+@item mm-inline-media-tests
+@vindex mm-inline-media-tests
+This is an alist where the key is a @acronym{MIME} type, the second element
+is a function to display the part @dfn{inline} (i.e., inside Emacs), and
+the third element is a form to be @code{eval}ed to say whether the part
+can be displayed inline.
-@example
-Content-Type: application/x-stuff;
- title*0*=us-ascii'en'This%20is%20even%20more%20;
- title*1*=%2A%2A%2Afun%2A%2A%2A%20;
- title*2="isn't it!"
-@end example
+This variable specifies whether a part @emph{can} be displayed inline,
+and, if so, how to do it. It does not say whether parts are
+@emph{actually} displayed inline.
-They usually aren't this bad, though.
+@item mm-inlined-types
+@vindex mm-inlined-types
+This, on the other hand, says what types are to be displayed inline, if
+they satisfy the conditions set by the variable above. It's a list of
+@acronym{MIME} media types.
-The following functions are defined by this library:
+@item mm-automatic-display
+@vindex mm-automatic-display
+This is a list of types that are to be displayed ``automatically'', but
+only if the above variable allows it. That is, only inlinable parts can
+be displayed automatically.
-@table @code
-@item rfc2231-parse-string
-@findex rfc2231-parse-string
-Parse a @code{Content-Type} header and return a list describing its
-elements.
+@item mm-automatic-external-display
+@vindex mm-automatic-external-display
+This is a list of types that will be displayed automatically in an
+external viewer.
-@example
-(rfc2231-parse-string
- "application/x-stuff;
- title*0*=us-ascii'en'This%20is%20even%20more%20;
- title*1*=%2A%2A%2Afun%2A%2A%2A%20;
- title*2=\"isn't it!\"")
-@result{} ("application/x-stuff"
- (title . "This is even more ***fun*** isn't it!"))
-@end example
+@item mm-keep-viewer-alive-types
+@vindex mm-keep-viewer-alive-types
+This is a list of media types for which the external viewer will not
+be killed when selecting a different article.
-@item rfc2231-get-value
-@findex rfc2231-get-value
-Takes one of the lists on the format above and returns
-the value of the specified attribute.
+@item mm-attachment-override-types
+@vindex mm-attachment-override-types
+Some @acronym{MIME} agents create parts that have a content-disposition of
+@samp{attachment}. This variable allows overriding that disposition and
+displaying the part inline. (Note that the disposition is only
+overridden if we are able to, and want to, display the part inline.)
-@item rfc2231-encode-string
-@findex rfc2231-encode-string
-Encode a parameter in headers likes @code{Content-Type} and
-@code{Content-Disposition}.
+@item mm-discouraged-alternatives
+@vindex mm-discouraged-alternatives
+List of @acronym{MIME} types that are discouraged when viewing
+@samp{multipart/alternative}. Viewing agents are supposed to view the
+last possible part of a message, as that is supposed to be the richest.
+However, users may prefer other types instead, and this list says what
+types are most unwanted. If, for instance, @samp{text/html} parts are
+very unwanted, and @samp{text/richtext} parts are somewhat unwanted,
+you could say something like:
-@end table
+@lisp
+(setq mm-discouraged-alternatives
+ '("text/html" "text/richtext")
+ mm-automatic-display
+ (remove "text/html" mm-automatic-display))
+@end lisp
+Adding @code{"image/.*"} might also be useful. Spammers use images as
+the preferred part of @samp{multipart/alternative} messages, so you might
+not notice there are other parts. See also
+@code{gnus-buttonized-mime-types}, @ref{MIME Commands, ,MIME Commands,
+gnus, Gnus Manual}. After adding @code{"multipart/alternative"} to
+@code{gnus-buttonized-mime-types} you can choose manually which
+alternative you'd like to view. For example, you can set those
+variables like:
-@node ietf-drums
-@section ietf-drums
+@lisp
+(setq gnus-buttonized-mime-types
+ '("multipart/alternative" "multipart/signed")
+ mm-discouraged-alternatives
+ '("text/html" "image/.*"))
+@end lisp
-@dfn{drums} is an IETF working group that is working on the replacement
-for RFC822.
+In this case, Gnus will display radio buttons for such a kind of spam
+message as follows:
-The functions provided by this library include:
+@example
+1. (*) multipart/alternative ( ) image/gif
-@table @code
-@item ietf-drums-remove-comments
-@findex ietf-drums-remove-comments
-Remove the comments from the argument and return the results.
+2. (*) text/plain ( ) text/html
+@end example
-@item ietf-drums-remove-whitespace
-@findex ietf-drums-remove-whitespace
-Remove linear white space from the string and return the results.
-Spaces inside quoted strings and comments are left untouched.
+@item mm-inline-large-images
+@vindex mm-inline-large-images
+When displaying inline images that are larger than the window, Emacs
+does not enable scrolling, which means that you cannot see the whole
+image. To prevent this, the library tries to determine the image size
+before displaying it inline, and if it doesn't fit the window, the
+library will display it externally (e.g. with @samp{ImageMagick} or
+@samp{xv}). Setting this variable to @code{t} disables this check and
+makes the library display all inline images as inline, regardless of
+their size.
-@item ietf-drums-get-comment
-@findex ietf-drums-get-comment
-Return the last most comment from the string.
+@item mm-inline-override-types
+@vindex mm-inline-override-types
+@code{mm-inlined-types} may include regular expressions, for example to
+specify that all @samp{text/.*} parts be displayed inline. If a user
+prefers to have a type that matches such a regular expression be treated
+as an attachment, that can be accomplished by setting this variable to a
+list containing that type. For example assuming @code{mm-inlined-types}
+includes @samp{text/.*}, then including @samp{text/html} in this
+variable will cause @samp{text/html} parts to be treated as attachments.
-@item ietf-drums-parse-address
-@findex ietf-drums-parse-address
-Parse an address string and return a list that contains the mailbox and
-the plain text name.
+@item mm-text-html-renderer
+@vindex mm-text-html-renderer
+This selects the function used to render @acronym{HTML}. The predefined
+renderers are selected by the symbols @code{w3},
+@code{w3m}@footnote{See @uref{http://emacs-w3m.namazu.org/} for more
+information about emacs-w3m}, @code{links}, @code{lynx},
+@code{w3m-standalone} or @code{html2text}. If @code{nil} use an
+external viewer. You can also specify a function, which will be
+called with a @acronym{MIME} handle as the argument.
-@item ietf-drums-parse-addresses
-@findex ietf-drums-parse-addresses
-Parse a string that contains any number of comma-separated addresses and
-return a list that contains mailbox/plain text pairs.
+@item mm-inline-text-html-with-images
+@vindex mm-inline-text-html-with-images
+Some @acronym{HTML} mails might have the trick of spammers using
+@samp{<img>} tags. It is likely to be intended to verify whether you
+have read the mail. You can prevent your personal informations from
+leaking by setting this option to @code{nil} (which is the default).
+It is currently ignored by Emacs/w3. For emacs-w3m, you may use the
+command @kbd{t} on the image anchor to show an image even if it is
+@code{nil}.@footnote{The command @kbd{T} will load all images. If you
+have set the option @code{w3m-key-binding} to @code{info}, use @kbd{i}
+or @kbd{I} instead.}
+
+@item mm-w3m-safe-url-regexp
+@vindex mm-w3m-safe-url-regexp
+A regular expression that matches safe URL names, i.e. URLs that are
+unlikely to leak personal information when rendering @acronym{HTML}
+email (the default value is @samp{\\`cid:}). If @code{nil} consider
+all URLs safe. In Gnus, this will be overridden according to the value
+of the variable @code{gnus-safe-html-newsgroups}, @xref{Various
+Various, ,Various Various, gnus, Gnus Manual}.
-@item ietf-drums-parse-date
-@findex ietf-drums-parse-date
-Parse a date string and return an Emacs time structure.
+@item mm-inline-text-html-with-w3m-keymap
+@vindex mm-inline-text-html-with-w3m-keymap
+You can use emacs-w3m command keys in the inlined text/html part by
+setting this option to non-@code{nil}. The default value is @code{t}.
-@item ietf-drums-narrow-to-header
-@findex ietf-drums-narrow-to-header
-Narrow the buffer to the header section of the current buffer.
+@item mm-external-terminal-program
+@vindex mm-external-terminal-program
+The program used to start an external terminal.
-@end table
+@item mm-enable-external
+@vindex mm-enable-external
+Indicate whether external @acronym{MIME} handlers should be used.
+If @code{t}, all defined external @acronym{MIME} handlers are used. If
+@code{nil}, files are saved to disk (@code{mailcap-save-binary-file}).
+If it is the symbol @code{ask}, you are prompted before the external
+@acronym{MIME} handler is invoked.
-@node rfc2047
-@section rfc2047
+When you launch an attachment through mailcap (@pxref{mailcap}) an
+attempt is made to use a safe viewer with the safest options---this isn't
+the case if you save it to disk and launch it in a different way
+(command line or double-clicking). Anyhow, if you want to be sure not
+to launch any external programs, set this variable to @code{nil} or
+@code{ask}.
-RFC2047 (Message Header Extensions for Non-ASCII Text) specifies how
-non-ASCII text in headers are to be encoded. This is actually rather
-complicated, so a number of variables are necessary to tweak what this
-library does.
+@end table
-The following variables are tweakable:
+@node Files and Directories
+@section Files and Directories
@table @code
-@item rfc2047-default-charset
-@vindex rfc2047-default-charset
-Characters in this charset should not be decoded by this library.
-This defaults to @code{iso-8859-1}.
-
-@item rfc2047-header-encoding-list
-@vindex rfc2047-header-encoding-list
-This is an alist of header / encoding-type pairs. Its main purpose is
-to prevent encoding of certain headers.
-The keys can either be header regexps, or @code{t}.
+@item mm-default-directory
+@vindex mm-default-directory
+The default directory for saving attachments. If @code{nil} use
+@code{default-directory}.
-The values can be either @code{nil}, in which case the header(s) in
-question won't be encoded, or @code{mime}, which means that they will be
-encoded.
+@item mm-tmp-directory
+@vindex mm-tmp-directory
+Directory for storing temporary files.
-@item rfc2047-charset-encoding-alist
-@vindex rfc2047-charset-encoding-alist
-RFC2047 specifies two forms of encoding---@code{Q} (a
-Quoted-Printable-like encoding) and @code{B} (base64). This alist
-specifies which charset should use which encoding.
+@item mm-file-name-rewrite-functions
+@vindex mm-file-name-rewrite-functions
+A list of functions used for rewriting file names of @acronym{MIME}
+parts. Each function is applied successively to the file name.
+Ready-made functions include
-@item rfc2047-encoding-function-alist
-@vindex rfc2047-encoding-function-alist
-This is an alist of encoding / function pairs. The encodings are
-@code{Q}, @code{B} and @code{nil}.
+@table @code
+@item mm-file-name-delete-control
+@findex mm-file-name-delete-control
+Delete all control characters.
+
+@item mm-file-name-delete-gotchas
+@findex mm-file-name-delete-gotchas
+Delete characters that could have unintended consequences when used
+with flawed shell scripts, i.e. @samp{|}, @samp{>} and @samp{<}; and
+@samp{-}, @samp{.} as the first character.
+
+@item mm-file-name-delete-whitespace
+@findex mm-file-name-delete-whitespace
+Remove all whitespace.
+
+@item mm-file-name-trim-whitespace
+@findex mm-file-name-trim-whitespace
+Remove leading and trailing whitespace.
+
+@item mm-file-name-collapse-whitespace
+@findex mm-file-name-collapse-whitespace
+Collapse multiple whitespace characters.
+
+@item mm-file-name-replace-whitespace
+@findex mm-file-name-replace-whitespace
+@vindex mm-file-name-replace-whitespace
+Replace whitespace with underscores. Set the variable
+@code{mm-file-name-replace-whitespace} to any other string if you do
+not like underscores.
+@end table
-@item rfc2047-q-encoding-alist
-@vindex rfc2047-q-encoding-alist
-The @code{Q} encoding isn't quite the same for all headers. Some
-headers allow a narrower range of characters, and that is what this
-variable is for. It's an alist of header regexps / allowable character
-ranges.
+The standard Emacs functions @code{capitalize}, @code{downcase},
+@code{upcase} and @code{upcase-initials} might also prove useful.
-@item rfc2047-encoded-word-regexp
-@vindex rfc2047-encoded-word-regexp
-When decoding words, this library looks for matches to this regexp.
+@item mm-path-name-rewrite-functions
+@vindex mm-path-name-rewrite-functions
+List of functions used for rewriting the full file names of @acronym{MIME}
+parts. This is used when viewing parts externally, and is meant for
+transforming the absolute name so that non-compliant programs can find
+the file where it's saved.
@end table
-Those were the variables, and these are this functions:
+@node New Viewers
+@section New Viewers
-@table @code
-@item rfc2047-narrow-to-field
-@findex rfc2047-narrow-to-field
-Narrow the buffer to the header on the current line.
+Here's an example viewer for displaying @code{text/enriched} inline:
-@item rfc2047-encode-message-header
-@findex rfc2047-encode-message-header
-Should be called narrowed to the header of a message. Encodes according
-to @code{rfc2047-header-encoding-alist}.
+@lisp
+(defun mm-display-enriched-inline (handle)
+ (let (text)
+ (with-temp-buffer
+ (mm-insert-part handle)
+ (save-window-excursion
+ (enriched-decode (point-min) (point-max))
+ (setq text (buffer-string))))
+ (mm-insert-inline handle text)))
+@end lisp
-@item rfc2047-encode-region
-@findex rfc2047-encode-region
-Encodes all encodable words in the region specified.
+We see that the function takes a @acronym{MIME} handle as its parameter. It
+then goes to a temporary buffer, inserts the text of the part, does some
+work on the text, stores the result, goes back to the buffer it was
+called from and inserts the result.
-@item rfc2047-encode-string
-@findex rfc2047-encode-string
-Encode a string and return the results.
+The two important helper functions here are @code{mm-insert-part} and
+@code{mm-insert-inline}. The first function inserts the text of the
+handle in the current buffer. It handles charset and/or content
+transfer decoding. The second function just inserts whatever text you
+tell it to insert, but it also sets things up so that the text can be
+``undisplayed'' in a convenient manner.
-@item rfc2047-decode-region
-@findex rfc2047-decode-region
-Decode the encoded words in the region.
-@item rfc2047-decode-string
-@findex rfc2047-decode-string
-Decode a string and return the results.
+@node Composing
+@chapter Composing
+@cindex Composing
+@cindex MIME Composing
+@cindex MML
+@cindex MIME Meta Language
-@end table
+Creating a @acronym{MIME} message is boring and non-trivial. Therefore,
+a library called @code{mml} has been defined that parses a language
+called @acronym{MML} (@acronym{MIME} Meta Language) and generates
+@acronym{MIME} messages.
+@findex mml-generate-mime
+The main interface function is @code{mml-generate-mime}. It will
+examine the contents of the current (narrowed-to) buffer and return a
+string containing the @acronym{MIME} message.
-@node time-date
-@section time-date
+@menu
+* Simple MML Example:: An example @acronym{MML} document.
+* MML Definition:: All valid @acronym{MML} elements.
+* Advanced MML Example:: Another example @acronym{MML} document.
+* Encoding Customization:: Variables that affect encoding.
+* Charset Translation:: How charsets are mapped from @sc{mule} to @acronym{MIME}.
+* Conversion:: Going from @acronym{MIME} to @acronym{MML} and vice versa.
+* Flowed text:: Soft and hard newlines.
+@end menu
-While not really a part of the @sc{mime} library, it is convenient to
-document this library here. It deals with parsing @code{Date} headers
-and manipulating time. (Not by using tesseracts, though, I'm sorry to
-say.)
-These functions convert between five formats: A date string, an Emacs
-time structure, a decoded time list, a second number, and a day number.
+@node Simple MML Example
+@section Simple MML Example
-Here's a bunch of time/date/second/day examples:
+Here's a simple @samp{multipart/alternative}:
@example
-(parse-time-string "Sat Sep 12 12:21:54 1998 +0200")
-@result{} (54 21 12 12 9 1998 6 nil 7200)
-
-(date-to-time "Sat Sep 12 12:21:54 1998 +0200")
-@result{} (13818 19266)
-
-(time-to-seconds '(13818 19266))
-@result{} 905595714.0
+<#multipart type=alternative>
+This is a plain text part.
+<#part type=text/enriched>
+<center>This is a centered enriched part</center>
+<#/multipart>
+@end example
-(seconds-to-time 905595714.0)
-@result{} (13818 19266 0)
+After running this through @code{mml-generate-mime}, we get this:
-(time-to-days '(13818 19266))
-@result{} 729644
+@example
+Content-Type: multipart/alternative; boundary="=-=-="
-(days-to-time 729644)
-@result{} (961933 65536)
-(time-since '(13818 19266))
-@result{} (0 430)
+--=-=-=
-(time-less-p '(13818 19266) '(13818 19145))
-@result{} nil
-(subtract-time '(13818 19266) '(13818 19145))
-@result{} (0 121)
+This is a plain text part.
-(days-between "Sat Sep 12 12:21:54 1998 +0200"
- "Sat Sep 07 12:21:54 1998 +0200")
-@result{} 5
+--=-=-=
+Content-Type: text/enriched
-(date-leap-year-p 2000)
-@result{} t
-(time-to-day-in-year '(13818 19266))
-@result{} 255
+<center>This is a centered enriched part</center>
-(time-to-number-of-days
- (time-since
- (date-to-time "Mon, 01 Jan 2001 02:22:26 GMT")))
-@result{} 4.146122685185185
+--=-=-=--
@end example
-And finally, we have @code{safe-date-to-time}, which does the same as
-@code{date-to-time}, but returns a zero time if the date is
-syntactically malformed.
-
-The five data representations used are the following:
-@table @var
-@item date
-An RFC822 (or similar) date string. For instance: @code{"Sat Sep 12
-12:21:54 1998 +0200"}.
+@node MML Definition
+@section MML Definition
-@item time
-An internal Emacs time. For instance: @code{(13818 26466)}.
+The @acronym{MML} language is very simple. It looks a bit like an SGML
+application, but it's not.
-@item seconds
-A floating point representation of the internal Emacs time. For
-instance: @code{905595714.0}.
+The main concept of @acronym{MML} is the @dfn{part}. Each part can be of a
+different type or use a different charset. The way to delineate a part
+is with a @samp{<#part ...>} tag. Multipart parts can be introduced
+with the @samp{<#multipart ...>} tag. Parts are ended by the
+@samp{<#/part>} or @samp{<#/multipart>} tags. Parts started with the
+@samp{<#part ...>} tags are also closed by the next open tag.
-@item days
-An integer number representing the number of days since 00000101. For
-instance: @code{729644}.
+There's also the @samp{<#external ...>} tag. These introduce
+@samp{external/message-body} parts.
-@item decoded time
-A list of decoded time. For instance: @code{(54 21 12 12 9 1998 6 t
-7200)}.
-@end table
+Each tag can contain zero or more parameters on the form
+@samp{parameter=value}. The values may be enclosed in quotation marks,
+but that's not necessary unless the value contains white space. So
+@samp{filename=/home/user/#hello$^yes} is perfectly valid.
-All the examples above represent the same moment.
+The following parameters have meaning in @acronym{MML}; parameters that have no
+meaning are ignored. The @acronym{MML} parameter names are the same as the
+@acronym{MIME} parameter names; the things in the parentheses say which
+header it will be used in.
-These are the functions available:
+@table @samp
+@item type
+The @acronym{MIME} type of the part (@code{Content-Type}).
-@table @code
-@item date-to-time
-Take a date and return a time.
+@item filename
+Use the contents of the file in the body of the part
+(@code{Content-Disposition}).
-@item time-to-seconds
-Take a time and return seconds.
+@item charset
+The contents of the body of the part are to be encoded in the character
+set specified (@code{Content-Type}). @xref{Charset Translation}.
-@item seconds-to-time
-Take seconds and return a time.
+@item name
+Might be used to suggest a file name if the part is to be saved
+to a file (@code{Content-Type}).
-@item time-to-days
-Take a time and return days.
+@item disposition
+Valid values are @samp{inline} and @samp{attachment}
+(@code{Content-Disposition}).
-@item days-to-time
-Take days and return a time.
+@item encoding
+Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and
+@samp{base64} (@code{Content-Transfer-Encoding}). @xref{Charset
+Translation}.
-@item date-to-day
-Take a date and return days.
+@item description
+A description of the part (@code{Content-Description}).
-@item time-to-number-of-days
-Take a time and return the number of days that represents.
+@item creation-date
+RFC822 date when the part was created (@code{Content-Disposition}).
-@item safe-date-to-time
-Take a date and return a time. If the date is not syntactically valid,
-return a "zero" date.
+@item modification-date
+RFC822 date when the part was modified (@code{Content-Disposition}).
-@item time-less-p
-Take two times and say whether the first time is less (i. e., earlier)
-than the second time.
+@item read-date
+RFC822 date when the part was read (@code{Content-Disposition}).
-@item time-since
-Take a time and return a time saying how long it was since that time.
+@item recipients
+Who to encrypt/sign the part to. This field is used to override any
+auto-detection based on the To/CC headers.
-@item subtract-time
-Take two times and subtract the second from the first. I. e., return
-the time between the two times.
+@item sender
+Identity used to sign the part. This field is used to override the
+default key used.
-@item days-between
-Take two days and return the number of days between those two days.
+@item size
+The size (in octets) of the part (@code{Content-Disposition}).
-@item date-leap-year-p
-Take a year number and say whether it's a leap year.
+@item sign
+What technology to sign this @acronym{MML} part with (@code{smime}, @code{pgp}
+or @code{pgpmime})
-@item time-to-day-in-year
-Take a time and return the day number within the year that the time is
-in.
+@item encrypt
+What technology to encrypt this @acronym{MML} part with (@code{smime},
+@code{pgp} or @code{pgpmime})
@end table
+Parameters for @samp{text/plain}:
-@node qp
-@section qp
+@table @samp
+@item format
+Formatting parameter for the text, valid values include @samp{fixed}
+(the default) and @samp{flowed}. Normally you do not specify this
+manually, since it requires the textual body to be formatted in a
+special way described in RFC 2646. @xref{Flowed text}.
+@end table
-This library deals with decoding and encoding Quoted-Printable text.
+Parameters for @samp{application/octet-stream}:
-Very briefly explained, qp encoding means translating all 8-bit
-characters (and lots of control characters) into things that look like
-@samp{=EF}; that is, an equal sign followed by the byte encoded as a hex
-string.
+@table @samp
+@item type
+Type of the part; informal---meant for human readers
+(@code{Content-Type}).
+@end table
-The following functions are defined by the library:
+Parameters for @samp{message/external-body}:
-@table @code
-@item quoted-printable-decode-region
-@findex quoted-printable-decode-region
-QP-decode all the encoded text in the specified region.
+@table @samp
+@item access-type
+A word indicating the supported access mechanism by which the file may
+be obtained. Values include @samp{ftp}, @samp{anon-ftp}, @samp{tftp},
+@samp{localfile}, and @samp{mailserver}. (@code{Content-Type}.)
-@item quoted-printable-decode-string
-@findex quoted-printable-decode-string
-Decode the QP-encoded text in a string and return the results.
+@item expiration
+The RFC822 date after which the file may no longer be fetched.
+(@code{Content-Type}.)
-@item quoted-printable-encode-region
-@findex quoted-printable-encode-region
-QP-encode all the encodable characters in the specified region. The third
-optional parameter @var{fold} specifies whether to fold long lines.
-(Long here means 72.)
+@item size
+The size (in octets) of the file. (@code{Content-Type}.)
-@item quoted-printable-encode-string
-@findex quoted-printable-encode-string
-QP-encode all the encodable characters in a string and return the
-results.
+@item permission
+Valid values are @samp{read} and @samp{read-write}
+(@code{Content-Type}).
@end table
+Parameters for @samp{sign=smime}:
-@node base64
-@section base64
-@cindex base64
-
-Base64 is an encoding that encodes three bytes into four characters,
-thereby increasing the size by about 33%. The alphabet used for
-encoding is very resistant to mangling during transit.
+@table @samp
-The following functions are defined by this library:
+@item keyfile
+File containing key and certificate for signer.
-@table @code
-@item base64-encode-region
-@findex base64-encode-region
-base64 encode the selected region. Return the length of the encoded
-text. Optional third argument @var{no-line-break} means do not break
-long lines into shorter lines.
+@end table
-@item base64-encode-string
-@findex base64-encode-string
-base64 encode a string and return the result.
+Parameters for @samp{encrypt=smime}:
-@item base64-decode-region
-@findex base64-decode-region
-base64 decode the selected region. Return the length of the decoded
-text. If the region can't be decoded, return @code{nil} and don't
-modify the buffer.
+@table @samp
-@item base64-decode-string
-@findex base64-decode-string
-base64 decode a string and return the result. If the string can't be
-decoded, @code{nil} is returned.
+@item certfile
+File containing certificate for recipient.
@end table
-@node binhex
-@section binhex
-@cindex binhex
-@cindex Apple
-@cindex Macintosh
-
-@code{binhex} is an encoding that originated in Macintosh environments.
-The following function is supplied to deal with these:
+@node Advanced MML Example
+@section Advanced MML Example
-@table @code
-@item binhex-decode-region
-@findex binhex-decode-region
-Decode the encoded text in the region. If given a third parameter, only
-decode the @code{binhex} header and return the filename.
+Here's a complex multipart message. It's a @samp{multipart/mixed} that
+contains many parts, one of which is a @samp{multipart/alternative}.
-@end table
+@example
+<#multipart type=mixed>
+<#part type=image/jpeg filename=~/rms.jpg disposition=inline>
+<#multipart type=alternative>
+This is a plain text part.
+<#part type=text/enriched name=enriched.txt>
+<center>This is a centered enriched part</center>
+<#/multipart>
+This is a new plain text part.
+<#part disposition=attachment>
+This plain text part is an attachment.
+<#/multipart>
+@end example
+And this is the resulting @acronym{MIME} message:
-@node uudecode
-@section uudecode
-@cindex uuencode
-@cindex uudecode
-
-@code{uuencode} is probably still the most popular encoding of binaries
-used on Usenet, although @code{base64} rules the mail world.
+@example
+Content-Type: multipart/mixed; boundary="=-=-="
-The following function is supplied by this package:
-@table @code
-@item uudecode-decode-region
-@findex uudecode-decode-region
-Decode the text in the region.
-@end table
+--=-=-=
-@node rfc1843
-@section rfc1843
-@cindex rfc1843
-@cindex HZ
-@cindex Chinese
-RFC1843 deals with mixing Chinese and ASCII characters in messages. In
-essence, RFC1843 switches between ASCII and Chinese by doing this:
+--=-=-=
+Content-Type: image/jpeg;
+ filename="~/rms.jpg"
+Content-Disposition: inline;
+ filename="~/rms.jpg"
+Content-Transfer-Encoding: base64
-@example
-This sentence is in ASCII.
-The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye.
-@end example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-Simple enough, and widely used in China.
+--=-=-=
+Content-Type: multipart/alternative; boundary="==-=-="
-The following functions are available to handle this encoding:
-@table @code
-@item rfc1843-decode-region
-Decode HZ-encoded text in the region.
+--==-=-=
-@item rfc1843-decode-string
-Decode a HZ-encoded string and return the result.
-@end table
+This is a plain text part.
+--==-=-=
+Content-Type: text/enriched;
+ name="enriched.txt"
-@node mailcap
-@section mailcap
-The @file{~/.mailcap} file is parsed by most @sc{mime}-aware message
-handlers and describes how elements are supposed to be displayed.
-Here's an example file:
+<center>This is a centered enriched part</center>
-@example
-image/*; gimp -8 %s
-audio/wav; wavplayer %s
-@end example
+--==-=-=--
-This says that all image files should be displayed with @code{gimp}, and
-that WAVE audio files should be played by @code{wavplayer}.
+--=-=-=
-The @code{mailcap} library parses this file, and provides functions for
-matching types.
+This is a new plain text part.
-@table @code
-@item mailcap-mime-data
-@vindex mailcap-mime-data
-This variable is an alist of alists containing backup viewing rules.
+--=-=-=
+Content-Disposition: attachment
-@end table
-Interface functions:
+This plain text part is an attachment.
-@table @code
-@item mailcap-parse-mailcaps
-@findex mailcap-parse-mailcaps
-Parse the @code{~/.mailcap} file.
+--=-=-=--
+@end example
-@item mailcap-mime-info
-Takes a @sc{mime} type as its argument and returns the matching viewer.
+@node Encoding Customization
+@section Encoding Customization
-@end table
+@table @code
+@item mm-body-charset-encoding-alist
+@vindex mm-body-charset-encoding-alist
+Mapping from @acronym{MIME} charset to encoding to use. This variable is
+usually used except, e.g., when other requirements force a specific
+encoding (digitally signed messages require 7bit encodings). The
+default is
+@lisp
+((iso-2022-jp . 7bit)
+ (iso-2022-jp-2 . 7bit)
+ (utf-16 . base64)
+ (utf-16be . base64)
+ (utf-16le . base64))
+@end lisp
+As an example, if you do not want to have ISO-8859-1 characters
+quoted-printable encoded, you may add @code{(iso-8859-1 . 8bit)} to
+this variable. You can override this setting on a per-message basis
+by using the @code{encoding} @acronym{MML} tag (@pxref{MML Definition}).
+
+@item mm-coding-system-priorities
+@vindex mm-coding-system-priorities
+Prioritize coding systems to use for outgoing messages. The default
+is @code{nil}, which means to use the defaults in Emacs, but is
+@code{(iso-8859-1 iso-2022-jp iso-2022-jp-2 shift_jis utf-8)} when
+running Emacs in the Japanese language environment. It is a list of
+coding system symbols (aliases of coding systems are also allowed, use
+@kbd{M-x describe-coding-system} to make sure you are specifying correct
+coding system names). For example, if you have configured Emacs
+to prefer UTF-8, but wish that outgoing messages should be sent in
+ISO-8859-1 if possible, you can set this variable to
+@code{(iso-8859-1)}. You can override this setting on a per-message
+basis by using the @code{charset} @acronym{MML} tag (@pxref{MML Definition}).
+
+As different hierarchies prefer different charsets, you may want to set
+@code{mm-coding-system-priorities} according to the hierarchy in Gnus.
+Here's an example:
-@node Decoding and Viewing
-@chapter Decoding and Viewing
+@c Corrections about preferred charsets are welcome. de, fr and fj
+@c should be correct, I don't know about the rest (so these are only
+@c examples):
+@lisp
+(add-to-list 'gnus-newsgroup-variables 'mm-coding-system-priorities)
+(setq gnus-parameters
+ (nconc
+ ;; Some charsets are just examples!
+ '(("^cn\\." ;; Chinese
+ (mm-coding-system-priorities
+ '(iso-8859-1 cn-big5 chinese-iso-7bit utf-8)))
+ ("^cz\\.\\|^pl\\." ;; Central and Eastern European
+ (mm-coding-system-priorities '(iso-8859-2 utf-8)))
+ ("^de\\." ;; German language
+ (mm-coding-system-priorities '(iso-8859-1 iso-8859-15 utf-8)))
+ ("^fr\\." ;; French
+ (mm-coding-system-priorities '(iso-8859-15 iso-8859-1 utf-8)))
+ ("^fj\\." ;; Japanese
+ (mm-coding-system-priorities
+ '(iso-8859-1 iso-2022-jp iso-2022-jp-2 shift_jis utf-8)))
+ ("^ru\\." ;; Cyrillic
+ (mm-coding-system-priorities
+ '(koi8-r iso-8859-5 iso-8859-1 utf-8))))
+ gnus-parameters))
+@end lisp
-This chapter deals with decoding and viewing @sc{mime} messages on a
-higher level.
+@item mm-content-transfer-encoding-defaults
+@vindex mm-content-transfer-encoding-defaults
+Mapping from @acronym{MIME} types to encoding to use. This variable is usually
+used except, e.g., when other requirements force a safer encoding
+(digitally signed messages require 7bit encoding). Besides the normal
+@acronym{MIME} encodings, @code{qp-or-base64} may be used to indicate that for
+each case the most efficient of quoted-printable and base64 should be
+used.
+
+@code{qp-or-base64} has another effect. It will fold long lines so that
+MIME parts may not be broken by MTA. So do @code{quoted-printable} and
+@code{base64}.
+
+Note that it affects body encoding only when a part is a raw forwarded
+message (which will be made by @code{gnus-summary-mail-forward} with the
+arg 2 for example) or is neither the @samp{text/*} type nor the
+@samp{message/*} type. Even though in those cases, you can override
+this setting on a per-message basis by using the @code{encoding}
+@acronym{MML} tag (@pxref{MML Definition}).
+
+@item mm-use-ultra-safe-encoding
+@vindex mm-use-ultra-safe-encoding
+When this is non-@code{nil}, it means that textual parts are encoded as
+quoted-printable if they contain lines longer than 76 characters or
+starting with "From " in the body. Non-7bit encodings (8bit, binary)
+are generally disallowed. This reduce the probability that a non-8bit
+clean MTA or MDA changes the message. This should never be set
+directly, but bound by other functions when necessary (e.g., when
+encoding messages that are to be digitally signed).
-The main idea is to first analyze a @sc{mime} article, and then allow
-other programs to do things based on the list of @dfn{handles} that are
-returned as a result of this analysis.
+@end table
-@menu
-* Dissection:: Analyzing a @sc{mime} message.
-* Non-MIME:: Analyzing a non-@sc{mime} message.
-* Handles:: Handle manipulations.
-* Display:: Displaying handles.
-* Customization:: Variables that affect display.
-* New Viewers:: How to write your own viewers.
-@end menu
+@node Charset Translation
+@section Charset Translation
+@cindex charsets
+During translation from @acronym{MML} to @acronym{MIME}, for each
+@acronym{MIME} part which has been composed inside Emacs, an appropriate
+charset has to be chosen.
-@node Dissection
-@section Dissection
+@vindex mail-parse-charset
+If you are running a non-@sc{mule} Emacs, this process is simple: If the
+part contains any non-@acronym{ASCII} (8-bit) characters, the @acronym{MIME} charset
+given by @code{mail-parse-charset} (a symbol) is used. (Never set this
+variable directly, though. If you want to change the default charset,
+please consult the documentation of the package which you use to process
+@acronym{MIME} messages.
+@xref{Various Message Variables, , Various Message Variables, message,
+ Message Manual}, for example.)
+If there are only @acronym{ASCII} characters, the @acronym{MIME} charset US-ASCII is
+used, of course.
-The @code{mm-dissect-buffer} is the function responsible for dissecting
-a @sc{mime} article. If given a multipart message, it will recursively
-descend the message, following the structure, and return a tree of
-@sc{mime} handles that describes the structure of the message.
+@cindex MULE
+@cindex UTF-8
+@cindex Unicode
+@vindex mm-mime-mule-charset-alist
+Things are slightly more complicated when running Emacs with @sc{mule}
+support. In this case, a list of the @sc{mule} charsets used in the
+part is obtained, and the @sc{mule} charsets are translated to
+@acronym{MIME} charsets by consulting the table provided by Emacs itself
+or the variable @code{mm-mime-mule-charset-alist} for XEmacs.
+If this results in a single @acronym{MIME} charset, this is used to encode
+the part. But if the resulting list of @acronym{MIME} charsets contains more
+than one element, two things can happen: If it is possible to encode the
+part via UTF-8, this charset is used. (For this, Emacs must support
+the @code{utf-8} coding system, and the part must consist entirely of
+characters which have Unicode counterparts.) If UTF-8 is not available
+for some reason, the part is split into several ones, so that each one
+can be encoded with a single @acronym{MIME} charset. The part can only be
+split at line boundaries, though---if more than one @acronym{MIME} charset is
+required to encode a single line, it is not possible to encode the part.
-@node Non-MIME
-@section Non-MIME
+When running Emacs with @sc{mule} support, the preferences for which
+coding system to use is inherited from Emacs itself. This means that
+if Emacs is set up to prefer UTF-8, it will be used when encoding
+messages. You can modify this by altering the
+@code{mm-coding-system-priorities} variable though (@pxref{Encoding
+Customization}).
-Gnus also understands some non-MIME attachments, such as postscript,
-uuencode, binhex, shar, forward, gnatsweb, pgp. Each of these features
-can be disabled by add an item into @code{mm-uu-configure-list}.
-For example,
+The charset to be used can be overridden by setting the @code{charset}
+@acronym{MML} tag (@pxref{MML Definition}) when composing the message.
-@lisp
-(require 'mm-uu)
-(add-to-list 'mm-uu-configure-list '(pgp-signed . disabled))
-@end lisp
+The encoding of characters (quoted-printable, 8bit etc) is orthogonal
+to the discussion here, and is controlled by the variables
+@code{mm-body-charset-encoding-alist} and
+@code{mm-content-transfer-encoding-defaults} (@pxref{Encoding
+Customization}).
-@table @code
-@item postscript
-@findex postscript
-Postscript file.
+@node Conversion
+@section Conversion
-@item uu
-@findex uu
-Uuencoded file.
+@findex mime-to-mml
+A (multipart) @acronym{MIME} message can be converted to @acronym{MML}
+with the @code{mime-to-mml} function. It works on the message in the
+current buffer, and substitutes @acronym{MML} markup for @acronym{MIME}
+boundaries. Non-textual parts do not have their contents in the buffer,
+but instead have the contents in separate buffers that are referred to
+from the @acronym{MML} tags.
-@item binhex
-@findex binhex
-Binhex encoded file.
+@findex mml-to-mime
+An @acronym{MML} message can be converted back to @acronym{MIME} by the
+@code{mml-to-mime} function.
-@item shar
-@findex shar
projects / gnus / blobdiff