\input texinfo
-@setfilename emacs-mime
+@include gnus-overrides.texi
+
+@setfilename emacs-mime.info
@settitle Emacs MIME Manual
+@include docstyle.texi
@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, 2003
- Free Software Foundation, Inc.
+Copyright @copyright{} 1998--2015 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.''
+@end quotation
+@end copying
-@tex
+@c Node ``Interface Functions'' uses non-ASCII characters
+
+@dircategory Emacs lisp libraries
+@direntry
+* Emacs MIME: (emacs-mime). Emacs MIME de/composition library.
+@end direntry
+@iftex
+@finalout
+@end iftex
+@setchapternewpage odd
@titlepage
+@ifset WEBHACKDEVEL
+@title Emacs MIME Manual (DEVELOPMENT VERSION)
+@end ifset
+@ifclear WEBHACKDEVEL
@title Emacs MIME Manual
+@end ifclear
@author by Lars Magne Ingebrigtsen
@page
-
@vskip 0pt plus 1filll
-Copyright @copyright{} 1998, 1999, 2000, 2001, 2002, 2003 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 manual is directed at users who want to modify the behaviour of
-the @sc{mime} encoding/decoding process or want a more detailed
-picture of how the Emacs @sc{mime} library works, and 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:: MML; a language for describing @sc{mime} parts.
+* 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.
* 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 Decoding and Viewing
@chapter Decoding and Viewing
-This chapter deals with decoding and viewing @sc{mime} messages on a
+This chapter deals with decoding and viewing @acronym{MIME} messages on a
higher level.
-The main idea is to first analyze a @sc{mime} article, and then allow
+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.
@menu
-* Dissection:: Analyzing a @sc{mime} message.
-* Non-MIME:: Analyzing a non-@sc{mime} message.
+* 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
@section Dissection
The @code{mm-dissect-buffer} is the function responsible for dissecting
-a @sc{mime} article. If given a multipart message, it will recursively
+a @acronym{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.
+@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-@sc{mime} attachments, such as
-postscript, uuencode, binhex, yenc, shar, forward, gnatsweb, pgp.
-Each of these features can be disabled by add an item into
+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
@table @code
@item postscript
@findex postscript
-Postscript file.
+PostScript file.
@item uu
@findex uu
@item forward
@findex forward
-Non-@sc{mime} forwarded message.
+Non-@acronym{MIME} forwarded message.
@item gnatsweb
@findex gnatsweb
@item pgp-signed
@findex pgp-signed
-PGP signed clear text.
+@acronym{PGP} signed clear text.
@item pgp-encrypted
@findex pgp-encrypted
-PGP encrypted clear text.
+@acronym{PGP} encrypted clear text.
@item pgp-key
@findex pgp-key
-PGP public keys.
+@acronym{PGP} public keys.
@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 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}.
+
+@item verbatim-marks
+@cindex verbatim-marks
+Slrn-style verbatim marks.
+
+@item LaTeX
+@cindex LaTeX
+LaTeX documents. It only works in groups matching
+@code{mm-uu-tex-groups-regexp}.
+
@end table
+@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}.
+
@node Handles
@section Handles
-A @sc{mime} handle is a list that fully describes a @sc{mime}
+A @acronym{MIME} handle is a list that fully describes a @acronym{MIME}
component.
The following macros can be used to access elements in a handle:
@table @code
@item mm-handle-buffer
@findex mm-handle-buffer
-Return the buffer that holds the contents of the undecoded @sc{mime}
+Return the buffer that holds the contents of the undecoded @acronym{MIME}
part.
@item mm-handle-type
@findex mm-handle-disposition
Return the parsed @code{Content-Disposition} of the part.
-@item mm-handle-disposition
-@findex mm-handle-disposition
-Return the description of the part.
-
@item mm-get-content-id
Returns the handle(s) referred to by @code{Content-ID}.
@item mm-inlinable-p
@findex mm-inlinable-p
-Say whether a @sc{mime} type can be displayed inline.
+Say whether a @acronym{MIME} type can be displayed inline.
@item mm-automatic-display-p
@findex mm-automatic-display-p
-Say whether a @sc{mime} type should be displayed automatically.
+Say whether a @acronym{MIME} type should be displayed automatically.
@item mm-destroy-part
@findex mm-destroy-part
@item mm-inline-media-tests
@vindex mm-inline-media-tests
-This is an alist where the key is a @sc{mime} type, the second element
+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.
@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
-@sc{mime} media types.
+@acronym{MIME} media types.
@item mm-automatic-display
@vindex mm-automatic-display
@item mm-attachment-override-types
@vindex mm-attachment-override-types
-Some @sc{mime} agents create parts that have a content-disposition of
+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 mm-discouraged-alternatives
@vindex mm-discouraged-alternatives
-List of @sc{mime} types that are discouraged when viewing
+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
(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:
+
+@lisp
+(setq gnus-buttonized-mime-types
+ '("multipart/alternative" "multipart/signed")
+ mm-discouraged-alternatives
+ '("text/html" "image/.*"))
+@end lisp
+
+In this case, Gnus will display radio buttons for such a kind of spam
+message as follows:
+
+@example
+1. (*) multipart/alternative ( ) image/gif
+
+2. (*) text/plain ( ) text/html
+@end example
+
@item mm-inline-large-images
@vindex mm-inline-large-images
-When displaying inline images that are larger than the window, XEmacs
+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
+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
+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.
+their size. If you set this variable to @code{resize}, the image will
+be displayed resized to fit in the window, if Emacs has the ability to
+resize images.
+
+@item mm-inline-large-images-proportion
+@vindex mm-inline-images-max-proportion
+The proportion used when resizing large images.
@item mm-inline-override-types
@vindex mm-inline-override-types
@item mm-text-html-renderer
@vindex mm-text-html-renderer
-This selects the function used to render @sc{html}. The predefined
-renderers are selected by the symbols @code{w3},
+This selects the function used to render @acronym{HTML}. The predefined
+renderers are selected by the symbols @code{gnus-article-html},
@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 @sc{mime} handle as the argument.
+called with a @acronym{MIME} handle as the argument.
@item mm-inline-text-html-with-images
@vindex mm-inline-text-html-with-images
-Some @sc{html} mails might have the trick of spammers using
+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
+have read the mail. You can prevent your personal information 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.}
+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 @sc{html} email
-(the default value is @samp{\\`cid:}). If @code{nil} consider all
-URLs safe.
+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 mm-inline-text-html-with-w3m-keymap
@vindex mm-inline-text-html-with-w3m-keymap
@vindex mm-external-terminal-program
The program used to start an external terminal.
+@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.
+
+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}.
+
@end table
+@node Files and Directories
+@section Files and Directories
+
+@table @code
+
+@item mm-default-directory
+@vindex mm-default-directory
+The default directory for saving attachments. If @code{nil} use
+@code{default-directory}.
+
+@item mm-tmp-directory
+@vindex mm-tmp-directory
+Directory for storing temporary files.
+
+@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
+
+@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
+
+The standard Emacs functions @code{capitalize}, @code{downcase},
+@code{upcase} and @code{upcase-initials} might also prove useful.
+
+@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
@node New Viewers
@section New Viewers
(mm-insert-inline handle text)))
@end lisp
-We see that the function takes a @sc{mime} handle as its parameter. It
+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.
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.
+``undisplayed'' in a convenient manner.
@node Composing
@cindex MML
@cindex MIME Meta Language
-Creating a @sc{mime} message is boring and non-trivial. Therefore, a
-library called @code{mml} has been defined that parses a language called
-MML (@sc{mime} Meta Language) and generates @sc{mime} messages.
+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 @sc{mime} message.
+string containing the @acronym{MIME} message.
@menu
-* Simple MML Example:: An example MML document.
-* MML Definition:: All valid MML elements.
-* Advanced MML Example:: Another example MML document.
+* 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 @sc{mime}.
-* Conversion:: Going from @sc{mime} to MML and vice versa.
+* 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
@node MML Definition
@section MML Definition
-The MML language is very simple. It looks a bit like an SGML
+The @acronym{MML} language is very simple. It looks a bit like an SGML
application, but it's not.
-The main concept of MML is the @dfn{part}. Each part can be of a
+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
but that's not necessary unless the value contains white space. So
@samp{filename=/home/user/#hello$^yes} is perfectly valid.
-The following parameters have meaning in MML; parameters that have no
-meaning are ignored. The MML parameter names are the same as the
-@sc{mime} parameter names; the things in the parentheses say which
+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.
@table @samp
@item type
-The @sc{mime} type of the part (@code{Content-Type}).
+The @acronym{MIME} type of the part (@code{Content-Type}).
@item filename
Use the contents of the file in the body of the part
(@code{Content-Disposition}).
+@item recipient-filename
+Use this as the file name in the generated @acronym{MIME} message for
+the recipient. That is, even if the file is called @file{foo.txt}
+locally, use this name instead in the @code{Content-Disposition} in
+the sent message.
+
@item charset
The contents of the body of the part are to be encoded in the character
-set speficied (@code{Content-Type}). @xref{Charset Translation}.
+set specified (@code{Content-Type}). @xref{Charset Translation}.
@item name
Might be used to suggest a file name if the part is to be saved
Who to encrypt/sign the part to. This field is used to override any
auto-detection based on the To/CC headers.
+@item sender
+Identity used to sign the part. This field is used to override the
+default key used.
+
@item size
The size (in octets) of the part (@code{Content-Disposition}).
@item sign
-What technology to sign this MML part with (@code{smime}, @code{pgp}
+What technology to sign this @acronym{MML} part with (@code{smime}, @code{pgp}
or @code{pgpmime})
@item encrypt
-What technology to encrypt this MML part with (@code{smime},
+What technology to encrypt this @acronym{MML} part with (@code{smime},
@code{pgp} or @code{pgpmime})
@end table
+Parameters for @samp{text/plain}:
+
+@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
+
Parameters for @samp{application/octet-stream}:
@table @samp
<#/multipart>
@end example
-And this is the resulting @sc{mime} message:
+And this is the resulting @acronym{MIME} message:
@example
Content-Type: multipart/mixed; boundary="=-=-="
@item mm-body-charset-encoding-alist
@vindex mm-body-charset-encoding-alist
-Mapping from @sc{mime} charset to encoding to use. This variable is
+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 @code{((iso-2022-jp . 7bit) (iso-2022-jp-2 . 7bit))}. As
-an example, if you do not want to have ISO-8859-1 characters
+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} MML tag (@pxref{MML Definition}).
+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. It is a list of
-coding system symbols (aliases of coding systems does not work, use
-@kbd{M-x describe-coding-system} to make sure you are not specifying
-an alias in this variable). For example, if you have configured Emacs
-to use 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-latin-1)}. You can override this setting on a per-message
-basis by using the @code{charset} MML tag (@pxref{MML Definition}).
+is @code{nil}, which means to use the defaults in Emacs, but is
+@code{(iso-8859-1 iso-2022-jp 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:
+
+@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 utf-8)))
+ ("^ru\\." ;; Cyrillic
+ (mm-coding-system-priorities
+ '(koi8-r iso-8859-5 iso-8859-1 utf-8))))
+ gnus-parameters))
+@end lisp
@item mm-content-transfer-encoding-defaults
@vindex mm-content-transfer-encoding-defaults
-Mapping from @sc{mime} types to encoding to use. This variable is usually
+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
-@sc{mime} encodings, @code{qp-or-base64} may be used to indicate that for
+(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. You can override this setting on a per-message basis by using
-the @code{encoding} MML tag (@pxref{MML Definition}).
+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
@section Charset Translation
@cindex charsets
-During translation from MML to @sc{mime}, for each @sc{mime} part which
-has been composed inside Emacs, an appropriate charset has to be chosen.
+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.
@vindex mail-parse-charset
If you are running a non-@sc{mule} Emacs, this process is simple: If the
-part contains any non-ASCII (8-bit) characters, the @sc{mime} charset
+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
-@sc{mime} messages.
+@acronym{MIME} messages.
@xref{Various Message Variables, , Various Message Variables, message,
Message Manual}, for example.)
-If there are only ASCII characters, the @sc{mime} charset US-ASCII is
+If there are only @acronym{ASCII} characters, the @acronym{MIME} charset US-ASCII is
used, of course.
@cindex MULE
@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 @sc{mime}
-charsets by consulting the variable @code{mm-mime-mule-charset-alist}.
-If this results in a single @sc{mime} charset, this is used to encode
-the part. But if the resulting list of @sc{mime} charsets contains more
+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 @sc{mime} charset. The part can only be
-split at line boundaries, though---if more than one @sc{mime} charset is
+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.
When running Emacs with @sc{mule} support, the preferences for which
@code{mm-coding-system-priorities} variable though (@pxref{Encoding
Customization}).
-The charset to be used can be overriden by setting the @code{charset}
-MML tag (@pxref{MML Definition}) when composing the message.
+The charset to be used can be overridden by setting the @code{charset}
+@acronym{MML} tag (@pxref{MML Definition}) when composing the message.
-The encoding of characters (quoted-printable, 8bit etc) is orthogonal
+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
@section Conversion
@findex mime-to-mml
-A (multipart) @sc{mime} message can be converted to MML with the
-@code{mime-to-mml} function. It works on the message in the current
-buffer, and substitutes MML markup for @sc{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 MML
-tags.
+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.
@findex mml-to-mime
-An MML message can be converted back to @sc{mime} by the
+An @acronym{MML} message can be converted back to @acronym{MIME} by the
@code{mml-to-mime} function.
These functions are in certain senses ``lossy''---you will not get back
-an identical message if you run @sc{mime-to-mml} and then
-@sc{mml-to-mime}. Not only will trivial things like the order of the
+an identical message if you run @code{mime-to-mml} and then
+@code{mml-to-mime}. Not only will trivial things like the order of the
headers differ, but the contents of the headers may also be different.
For instance, the original message may use base64 encoding on text,
-while @sc{mml-to-mime} may decide to use quoted-printable encoding, and
+while @code{mml-to-mime} may decide to use quoted-printable encoding, and
so on.
In essence, however, these two functions should be the inverse of each
@section Flowed text
@cindex format=flowed
-The Emacs @sc{mime} library will respect the @code{use-hard-newlines}
+The Emacs @acronym{MIME} library will respect the @code{use-hard-newlines}
variable (@pxref{Hard and Soft Newlines, ,Hard and Soft Newlines,
emacs, Emacs Manual}) when encoding a message, and the
``format=flowed'' Content-Type parameter when decoding a message.
-On encoding text, lines terminated by soft newline characters are
-filled together and wrapped after the column decided by
-@code{fill-flowed-encode-column}. This variable controls how the text
-will look in a client that does not support flowed text, the default
-is to wrap after 66 characters. If hard newline characters are not
-present in the buffer, no flow encoding occurs.
+On encoding text, regardless of @code{use-hard-newlines}, lines
+terminated by soft newline characters are filled together and wrapped
+after the column decided by @code{fill-flowed-encode-column}.
+Quotation marks (matching @samp{^>* ?}) are respected. The variable
+controls how the text will look in a client that does not support
+flowed text, the default is to wrap after 66 characters. If hard
+newline characters are not present in the buffer, no flow encoding
+occurs.
+
+You can customize the value of the @code{mml-enable-flowed} variable
+to enable or disable the flowed encoding usage when newline
+characters are present in the buffer.
On decoding flowed text, lines with soft newline characters are filled
together and wrapped after the column decided by
@code{fill-flowed-display-column}. The default is to wrap after
@code{fill-column}.
-
+@table @code
+@item mm-fill-flowed
+@vindex mm-fill-flowed
+If non-@code{nil} a format=flowed article will be displayed flowed.
+@end table
@node Interface Functions
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
+@code{Content-Type} header that only allows @acronym{ASCII} characters in the
parameter list. RFC2231 expands on RFC2045 syntax to provide a scheme
-for continuation headers and non-ASCII characters.
+for continuation headers and non-@acronym{ASCII} characters.
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
library, one must choose between the old version of the library and the
new version of the library.
-The Emacs @sc{mime} library takes a different tack. It defines a
+The Emacs @acronym{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
@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?=}.
+Encode the non-@acronym{ASCII} words in the region. For instance,
+@samp{Naïve} is encoded as @samp{=?iso-8859-1?q?Na=EFve?=}.
@item mail-encode-encoded-word-buffer
@findex mail-encode-encoded-word-buffer
-Encode the non-ASCII words in the current buffer. This function is
+Encode the non-@acronym{ASCII} words in the current buffer. This function is
meant to be called narrowed to the headers of a message.
@item mail-encode-encoded-word-string
@example
(mail-encode-encoded-word-string
- "This is naïve, baby")
+ "This is naïve, baby")
@result{} "This is =?iso-8859-1?q?na=EFve,?= baby"
@end example
@example
(mail-decode-encoded-word-string
"This is =?iso-8859-1?q?na=EFve,?= baby")
-@result{} "This is naïve, baby"
+@result{} "This is naïve, baby"
@end example
@end table
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
+on. High-level functionality is dealt with in the first chapter
(@pxref{Decoding and Viewing}).
@menu
@node rfc2045
@section rfc2045
-RFC2045 is the ``main'' @sc{mime} document, and as such, one would
+RFC2045 is the ``main'' @acronym{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.
@node rfc2047
@section rfc2047
-RFC2047 (Message Header Extensions for Non-ASCII Text) specifies how
-non-ASCII text in headers are to be encoded. This is actually rather
+RFC2047 (Message Header Extensions for Non-@acronym{ASCII} Text) specifies how
+non-@acronym{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.
The following variables are tweakable:
@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-alist
@vindex rfc2047-header-encoding-alist
This is an alist of header / encoding-type pairs. Its main purpose is
The keys can either be header regexps, or @code{t}.
-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.
+The values can be @code{nil}, in which case the header(s) in question
+won't be encoded, @code{mime}, which means that they will be encoded, or
+@code{address-mime}, which means the header(s) will be encoded carefully
+assuming they contain addresses.
@item rfc2047-charset-encoding-alist
@vindex rfc2047-charset-encoding-alist
Quoted-Printable-like encoding) and @code{B} (base64). This alist
specifies which charset should use which encoding.
-@item rfc2047-encoding-function-alist
-@vindex rfc2047-encoding-function-alist
+@item rfc2047-encode-function-alist
+@vindex rfc2047-encode-function-alist
This is an alist of encoding / function pairs. The encodings are
@code{Q}, @code{B} and @code{nil}.
-@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.
-
@item rfc2047-encoded-word-regexp
@vindex rfc2047-encoded-word-regexp
When decoding words, this library looks for matches to this regexp.
+@item rfc2047-encoded-word-regexp-loose
+@vindex rfc2047-encoded-word-regexp-loose
+This is a version from which the regexp for the Q encoding pattern of
+@code{rfc2047-encoded-word-regexp} is made loose.
+
+@item rfc2047-encode-encoded-words
+@vindex rfc2047-encode-encoded-words
+The boolean variable specifies whether encoded words
+(e.g., @samp{=?us-ascii?q?hello?=}) should be encoded again.
+@code{rfc2047-encoded-word-regexp} is used to look for such words.
+
+@item rfc2047-allow-irregular-q-encoded-words
+@vindex rfc2047-allow-irregular-q-encoded-words
+The boolean variable specifies whether irregular Q encoded words
+(e.g., @samp{=?us-ascii?q?hello??=}) should be decoded. If it is
+non-@code{nil}, @code{rfc2047-encoded-word-regexp-loose} is used instead
+of @code{rfc2047-encoded-word-regexp} to look for encoded words.
+
@end table
Those were the variables, and these are this functions:
@findex rfc2047-decode-string
Decode a string and return the results.
+@item rfc2047-encode-parameter
+@findex rfc2047-encode-parameter
+Encode a parameter in the RFC2047-like style. This is a substitution
+for the @code{rfc2231-encode-string} function, that is the standard but
+many mailers don't support it. @xref{rfc2231}.
+
@end table
@node time-date
@section time-date
-While not really a part of the @sc{mime} library, it is convenient to
+While not really a part of the @acronym{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.)
(date-to-time "Sat Sep 12 12:21:54 1998 +0200")
@result{} (13818 19266)
-(time-to-seconds '(13818 19266))
+(float-time '(13818 19266))
@result{} 905595714.0
(seconds-to-time 905595714.0)
-@result{} (13818 19266 0)
+@result{} (13818 19266 0 0)
(time-to-days '(13818 19266))
@result{} 729644
(days-to-time 729644)
-@result{} (961933 65536)
+@result{} (961933 512)
(time-since '(13818 19266))
-@result{} (0 430)
+@result{} (6797 9607 984839 247000)
(time-less-p '(13818 19266) '(13818 19145))
@result{} nil
(time-to-number-of-days
(time-since
(date-to-time "Mon, 01 Jan 2001 02:22:26 GMT")))
-@result{} 4.146122685185185
+@result{} 4314.095589286675
@end example
And finally, we have @code{safe-date-to-time}, which does the same as
12:21:54 1998 +0200"}.
@item time
-An internal Emacs time. For instance: @code{(13818 26466)}.
+An internal Emacs time. For instance: @code{(13818 26466 0 0)}.
@item seconds
A floating point representation of the internal Emacs time. For
@item date-to-time
Take a date and return a time.
-@item time-to-seconds
-Take a time and return seconds.
+@item float-time
+Take a time and return seconds. (This is a built-in function.)
@item seconds-to-time
Take seconds and return a time.
@item safe-date-to-time
Take a date and return a time. If the date is not syntactically valid,
-return a "zero" date.
+return a ``zero'' time.
@item time-less-p
-Take two times and say whether the first time is less (i. e., earlier)
+Take two times and say whether the first time is less (i.e., earlier)
than the second time.
@item time-since
Take a time and return a time saying how long it was since that time.
@item subtract-time
-Take two times and subtract the second from the first. I. e., return
+Take two times and subtract the second from the first. I.e., return
the time between the two times.
@item days-between
@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:
+RFC1843 deals with mixing Chinese and @acronym{ASCII} characters in messages. In
+essence, RFC1843 switches between @acronym{ASCII} and Chinese by doing this:
@example
-This sentence is in ASCII.
+This sentence is in @acronym{ASCII}.
The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye.
@end example
@node mailcap
@section mailcap
-The @file{~/.mailcap} file is parsed by most @sc{mime}-aware message
+The @file{~/.mailcap} file is parsed by most @acronym{MIME}-aware message
handlers and describes how elements are supposed to be displayed.
Here's an example file:
Parse the @file{~/.mailcap} file.
@item mailcap-mime-info
-Takes a @sc{mime} type as its argument and returns the matching viewer.
+Takes a @acronym{MIME} type as its argument and returns the matching viewer.
@end table
@node Standards
@chapter Standards
-The Emacs @sc{mime} library implements handling of various elements
+The Emacs @acronym{MIME} library implements handling of various elements
according to a (somewhat) large number of RFCs, drafts and standards
documents. This chapter lists the relevant ones. They can all be
fetched from @uref{http://quimby.gnus.org/notes/}.
Media Types
@item RFC2047
-Message Header Extensions for Non-ASCII Text
+Message Header Extensions for Non-@acronym{ASCII} Text
@item RFC2048
Registration Procedures
Conformance Criteria and Examples
@item RFC2231
-@sc{mime} Parameter Value and Encoded Word Extensions: Character Sets,
+@acronym{MIME} Parameter Value and Encoded Word Extensions: Character Sets,
Languages, and Continuations
@item RFC1843
-HZ - A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and
-ASCII characters
+HZ---A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and
+@acronym{ASCII} characters
@item draft-ietf-drums-msg-fmt-05.txt
Draft for the successor of RFC822
@item RFC2112
-The @sc{mime} Multipart/Related Content-type
+The @acronym{MIME} Multipart/Related Content-type
@item RFC1892
The Multipart/Report Content Type for the Reporting of Mail System
@end table
+@node GNU Free Documentation License
+@chapter GNU Free Documentation License
+@include doclicense.texi
@node Index
@chapter Index
@printindex cp
-@summarycontents
-@contents
@bye
\f
@c Local Variables:
@c mode: texinfo
-@c coding: iso-8859-1
+@c coding: utf-8
@c End:
projects / gnus / blobdiff