-\input texinfo @c -*-texinfo-*-
+\input texinfo
@setfilename emacs-mime
@settitle Emacs MIME Manual
@synindex fn cp
@synindex vr cp
@synindex pg cp
-@c @direntry
-@c * Emacs MIME: (emacs-mime). The MIME de/composition library.
-@c @end direntry
+@dircategory Emacs
+@direntry
+* Emacs MIME: (emacs-mime). The MIME de/composition library.
+@end direntry
@iftex
@finalout
@end iftex
@setchapternewpage odd
-@ifinfo
+@ifnottex
This file documents the Emacs MIME interface functionality.
-Copyright (C) 1996 Free Software Foundation, Inc.
+Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003
+ Free Software Foundation, Inc.
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
+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 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.
-@ignore
-Permission is granted to process this file through Tex and print the
-results, provided the printed document carries copying permission
-notice identical to this one except for the removal of this paragraph
-(this paragraph not being relevant to the printed 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.''
-@end ignore
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided also that the
-entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions.
-@end ifinfo
+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
@tex
@page
@vskip 0pt plus 1filll
-Copyright @copyright{} 1998 Free Software Foundation, Inc.
-
-Permission is granted to make and distribute verbatim copies of
-this manual provided the copyright notice and this permission notice
-are preserved on all copies.
-
-Permission is granted to copy and distribute modified versions of this
-manual under the conditions for verbatim copying, provided that the
-entire resulting derived work is distributed under the terms of a
-permission notice identical to this one.
-
-Permission is granted to copy and distribute translations of this manual
-into another language, under the above conditions for modified versions.
-
+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.
@end titlepage
@page
@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 behaviour 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.
@menu
-* Basic Functions:: Utility and basic parsing functions.
* 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.
+* Standards:: A summary of RFCs and working documents used.
* Index:: Function and variable index.
@end menu
-@node Basic Functions
-@chapter Basic Functions
+@node Decoding and Viewing
+@chapter Decoding and Viewing
-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}).
+This chapter deals with decoding and viewing @acronym{MIME} messages on a
+higher level.
+
+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
-* mail-parse:: The generalized @sc{mime} and mail interface.
-* rfc2231:: Parsing @code{Content-Type} headers.
-* 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.
-* mailcap:: How parts are displayed is specified by the @file{.mailcap} file
+* 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
-@node mail-parse
-@section mail-parse
+@node Dissection
+@section Dissection
+
+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
+(require 'mm-uu)
+(add-to-list 'mm-uu-configure-list '(pgp-signed . disabled))
+@end lisp
+
+@table @code
+@item postscript
+@findex postscript
+Postscript file.
+
+@item uu
+@findex uu
+Uuencoded file.
+
+@item binhex
+@findex binhex
+Binhex encoded file.
+
+@item yenc
+@findex yenc
+Yenc encoded file.
+
+@item shar
+@findex shar
+Shar archive file.
+
+@item forward
+@findex forward
+Non-@acronym{MIME} forwarded message.
+
+@item gnatsweb
+@findex gnatsweb
+Gnatsweb attachment.
+
+@item pgp-signed
+@findex pgp-signed
+@acronym{PGP} signed clear text.
+
+@item pgp-encrypted
+@findex pgp-encrypted
+@acronym{PGP} encrypted clear text.
+
+@item pgp-key
+@findex pgp-key
+@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}.
+
+@end table
+
+@node Handles
+@section Handles
+
+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 @acronym{MIME}
+part.
+
+@item mm-handle-type
+@findex mm-handle-type
+Return the parsed @code{Content-Type} of the part.
+
+@item mm-handle-encoding
+@findex mm-handle-encoding
+Return the @code{Content-Transfer-Encoding} of the part.
+
+@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 mm-handle-set-undisplayer
+@findex mm-handle-set-undisplayer
+Set the undisplayer object.
+
+@item mm-handle-disposition
+@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}.
+
+@end table
-It is perhaps misleading to place the @code{mail-parse} library in this
-chapter. It is not a basic low-level library---rather, it is an
-abstraction over the actual low-level libraries that are described in the
-subsequent sections.
+
+@node Display
+@section Display
+
+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).
+
+@item mm-inlinable-p
+@findex mm-inlinable-p
+Say whether a @acronym{MIME} type can be displayed inline.
+
+@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.
+
+@item mm-save-part
+@findex mm-save-part
+Offer to save the part in a file.
+
+@item mm-pipe-part
+@findex mm-pipe-part
+Offer to pipe the part to some process.
+
+@item mm-interactively-view-part
+@findex mm-interactively-view-part
+Prompt for a mailcap method to use to view the part.
+
+@end table
+
+
+@node Display Customization
+@section Display Customization
+
+@table @code
+
+@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.
+
+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.
+
+@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.
+
+@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.
+
+@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.
+
+@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 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 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:
+
+@lisp
+(setq mm-discouraged-alternatives
+ '("text/html" "text/richtext")
+ mm-automatic-display
+ (remove "text/html" mm-automatic-display))
+@end lisp
+
+@item mm-inline-large-images
+@vindex mm-inline-large-images
+When displaying inline images that are larger than the window, XEmacs
+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 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 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 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.
+
+@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 mm-external-terminal-program
+@vindex mm-external-terminal-program
+The program used to start an external terminal.
+
+@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
+
+Here's an example viewer for displaying @code{text/enriched} inline:
+
+@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
+
+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.
+
+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.
+
+
+@node Composing
+@chapter Composing
+@cindex Composing
+@cindex MIME Composing
+@cindex MML
+@cindex MIME Meta Language
+
+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.
+
+@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
+
+
+@node Simple MML Example
+@section Simple MML Example
+
+Here's a simple @samp{multipart/alternative}:
+
+@example
+<#multipart type=alternative>
+This is a plain text part.
+<#part type=text/enriched>
+<center>This is a centered enriched part</center>
+<#/multipart>
+@end example
+
+After running this through @code{mml-generate-mime}, we get this:
+
+@example
+Content-Type: multipart/alternative; boundary="=-=-="
+
+
+--=-=-=
+
+
+This is a plain text part.
+
+--=-=-=
+Content-Type: text/enriched
+
+
+<center>This is a centered enriched part</center>
+
+--=-=-=--
+@end example
+
+
+@node MML Definition
+@section MML Definition
+
+The @acronym{MML} language is very simple. It looks a bit like an SGML
+application, but it's not.
+
+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.
+
+There's also the @samp{<#external ...>} tag. These introduce
+@samp{external/message-body} parts.
+
+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.
+
+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 @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 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 name
+Might be used to suggest a file name if the part is to be saved
+to a file (@code{Content-Type}).
+
+@item disposition
+Valid values are @samp{inline} and @samp{attachment}
+(@code{Content-Disposition}).
+
+@item encoding
+Valid values are @samp{7bit}, @samp{8bit}, @samp{quoted-printable} and
+@samp{base64} (@code{Content-Transfer-Encoding}). @xref{Charset
+Translation}.
+
+@item description
+A description of the part (@code{Content-Description}).
+
+@item creation-date
+RFC822 date when the part was created (@code{Content-Disposition}).
+
+@item modification-date
+RFC822 date when the part was modified (@code{Content-Disposition}).
+
+@item read-date
+RFC822 date when the part was read (@code{Content-Disposition}).
+
+@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 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 @acronym{MML} part with (@code{smime}, @code{pgp}
+or @code{pgpmime})
+
+@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}:
+
+@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
+@item type
+Type of the part; informal---meant for human readers
+(@code{Content-Type}).
+@end table
+
+Parameters for @samp{message/external-body}:
+
+@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 expiration
+The RFC822 date after which the file may no longer be fetched.
+(@code{Content-Type}.)
+
+@item size
+The size (in octets) of the file. (@code{Content-Type}.)
+
+@item permission
+Valid values are @samp{read} and @samp{read-write}
+(@code{Content-Type}).
+
+@end table
+
+Parameters for @samp{sign=smime}:
+
+@table @samp
+
+@item keyfile
+File containing key and certificate for signer.
+
+@end table
+
+Parameters for @samp{encrypt=smime}:
+
+@table @samp
+
+@item certfile
+File containing certificate for recipient.
+
+@end table
+
+
+@node Advanced MML Example
+@section Advanced MML Example
+
+Here's a complex multipart message. It's a @samp{multipart/mixed} that
+contains many parts, one of which is a @samp{multipart/alternative}.
+
+@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:
+
+@example
+Content-Type: multipart/mixed; boundary="=-=-="
+
+
+--=-=-=
+
+
+
+--=-=-=
+Content-Type: image/jpeg;
+ filename="~/rms.jpg"
+Content-Disposition: inline;
+ filename="~/rms.jpg"
+Content-Transfer-Encoding: base64
+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+
+--=-=-=
+Content-Type: multipart/alternative; boundary="==-=-="
+
+
+--==-=-=
+
+
+This is a plain text part.
+
+--==-=-=
+Content-Type: text/enriched;
+ name="enriched.txt"
+
+
+<center>This is a centered enriched part</center>
+
+--==-=-=--
+
+--=-=-=
+
+This is a new plain text part.
+
+--=-=-=
+Content-Disposition: attachment
+
+
+This plain text part is an attachment.
+
+--=-=-=--
+@end example
+
+@node Encoding Customization
+@section Encoding Customization
+
+@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. 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 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} @acronym{MML} tag (@pxref{MML Definition}).
+
+@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. 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).
+
+@end table
+
+@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.
+
+@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.
+
+@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 variable @code{mm-mime-mule-charset-alist}.
+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.
+
+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}).
+
+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
+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}).
+
+@node Conversion
+@section Conversion
+
+@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.
+
+@findex mml-to-mime
+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 @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 @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
+other. The resulting contents of the message should remain equivalent,
+if not identical.
+
+
+@node Flowed text
+@section Flowed text
+@cindex format=flowed
+
+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, 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.
+
+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}.
+
+
+
+
+@node Interface Functions
+@chapter Interface Functions
+@cindex interface functions
+@cindex mail-parse
+
+The @code{mail-parse} library is an abstraction over the actual
+low-level libraries that are described in the next chapter.
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 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 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
+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:
@example
(mail-header-parse-content-type
"image/gif; name=\"b980912.gif\"")
-=> ("image/gif" (name . "b980912.gif"))
+@result{} ("image/gif" (name . "b980912.gif"))
@end example
@item mail-header-parse-content-disposition
@example
(mail-content-type-get
'("image/gif" (name . "b980912.gif")) 'name)
-=> "b980912.gif"
+@result{} "b980912.gif"
@end example
+@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 mail-header-remove-comments
@findex mail-header-remove-comments
Return a comment-free version of a header.
@example
(mail-header-remove-comments
"Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
-=> "Gnus/5.070027 "
+@result{} "Gnus/5.070027 "
@end example
@item mail-header-remove-whitespace
@example
(mail-header-remove-whitespace
"image/gif; name=\"Name with spaces\"")
-=> "image/gif;name=\"Name with spaces\""
+@result{} "image/gif;name=\"Name with spaces\""
@end example
@item mail-header-get-comment
Return the last comment in a header.
@example
-(mail-header-get-comment
+(mail-header-get-comment
"Gnus/5.070027 (Pterodactyl Gnus v0.27) (Finnish Landrace)")
-=> "Finnish Landrace"
+@result{} "Finnish Landrace"
@end example
@item mail-header-parse-address
@example
(mail-header-parse-address
"Hrvoje Niksic <hniksic@@srce.hr>")
-=> ("hniksic@@srce.hr" . "Hrvoje Niksic")
+@result{} ("hniksic@@srce.hr" . "Hrvoje Niksic")
@end example
@item mail-header-parse-addresses
@example
(mail-header-parse-addresses
"Hrvoje Niksic <hniksic@@srce.hr>, Steinar Bang <sb@@metis.no>")
-=> (("hniksic@@srce.hr" . "Hrvoje Niksic")
+@result{} (("hniksic@@srce.hr" . "Hrvoje Niksic")
("sb@@metis.no" . "Steinar Bang"))
@end example
@item mail-header-narrow-to-field
@findex mail-header-narrow-to-field
-Narrow the buffer to the header under point.
+Narrow the buffer to the header under point. Understands continuation
+headers.
+
+@item mail-header-fold-field
+@findex mail-header-fold-field
+Fold the header under point.
+
+@item mail-header-unfold-field
+@findex mail-header-unfold-field
+Unfold the header under point.
+
+@item mail-header-field-value
+@findex mail-header-field-value
+Return the value of the field under point.
@item mail-encode-encoded-word-region
@findex mail-encode-encoded-word-region
-Encode the non-ASCII words in the region. For instance,
+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 =?iso-8859-1?q?na=EFve,?= baby"
+@result{} "This is =?iso-8859-1?q?na=EFve,?= baby"
@end example
@item mail-decode-encoded-word-region
@example
(mail-decode-encoded-word-string
"This is =?iso-8859-1?q?na=EFve,?= baby")
-=> "This is naïve, baby"
+@result{} "This is naïve, baby"
@end example
@end table
-Currently, @code{mail-parse} is an abstraction over @code{drums},
-@code{rfc2047} and @code{rfc2231}. These are documented in the
-subsequent sections.
+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.
+
+
+
+@node Basic Functions
+@chapter Basic Functions
+
+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.
+* yenc:: Yenc decoding.
+* rfc1843:: Decoding HZ-encoded text.
+* mailcap:: How parts are displayed is specified by the @file{.mailcap} file
+@end menu
+
+
+@node rfc2045
+@section rfc2045
+
+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.
+
+So @file{rfc2045.el} has only a single function:
+
+@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
@example
(rfc2231-parse-string
- "application/x-stuff;
+ "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!\"")
-=> ("application/x-stuff"
+@result{} ("application/x-stuff"
(title . "This is even more ***fun*** isn't it!"))
@end example
@item rfc2231-get-value
@findex rfc2231-get-value
-Takes one of the lists on the format above and return
+Takes one of the lists on the format above and returns
the value of the specified attribute.
+@item rfc2231-encode-string
+@findex rfc2231-encode-string
+Encode a parameter in headers likes @code{Content-Type} and
+@code{Content-Disposition}.
+
@end table
-@node drums
-@section drums
+@node ietf-drums
+@section ietf-drums
@dfn{drums} is an IETF working group that is working on the replacement
for RFC822.
The functions provided by this library include:
@table @code
-@item drums-remove-comments
-@findex drums-remove-comments
+@item ietf-drums-remove-comments
+@findex ietf-drums-remove-comments
Remove the comments from the argument and return the results.
-@item drums-remove-whitespace
-@findex drums-remove-whitespace
+@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 drums-get-comment
-@findex drums-get-comment
+@item ietf-drums-get-comment
+@findex ietf-drums-get-comment
Return the last most comment from the string.
-@item drums-parse-address
-@findex drums-parse-address
+@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 drums-parse-addresses
-@findex drums-parse-addresses
+@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 drums-parse-date
-@findex drums-parse-date
+@item ietf-drums-parse-date
+@findex ietf-drums-parse-date
Parse a date string and return an Emacs time structure.
-@item drums-narrow-to-header
-@findex drums-narrow-to-header
+@item ietf-drums-narrow-to-header
+@findex ietf-drums-narrow-to-header
Narrow the buffer to the header section of the current buffer.
@end table
@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.
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
+@item rfc2047-header-encoding-alist
+@vindex rfc2047-header-encoding-alist
This is an alist of header / encoding-type pairs. Its main purpose is
to prevent encoding of certain headers.
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.
+ranges.
@item rfc2047-encoded-word-regexp
@vindex rfc2047-encoded-word-regexp
-When decoding words, this library looks for matches to this regexp.
+When decoding words, this library looks for matches to this regexp.
@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.)
-These functions converts between five formats: A date string, an Emacs
+These functions convert between five formats: A date string, an Emacs
time structure, a decoded time list, a second number, and a day number.
-The functions have quite self-explanatory names, so the following just
-gives an overview of which functions are available.
+Here's a bunch of time/date/second/day examples:
@example
(parse-time-string "Sat Sep 12 12:21:54 1998 +0200")
-=> (54 21 12 12 9 1998 6 nil 7200)
+@result{} (54 21 12 12 9 1998 6 nil 7200)
(date-to-time "Sat Sep 12 12:21:54 1998 +0200")
-=> (13818 19266)
+@result{} (13818 19266)
(time-to-seconds '(13818 19266))
-=> 905595714.0
+@result{} 905595714.0
(seconds-to-time 905595714.0)
-=> (13818 19266 0)
+@result{} (13818 19266 0)
-(time-to-day '(13818 19266))
-=> 729644
+(time-to-days '(13818 19266))
+@result{} 729644
(days-to-time 729644)
-=> (961933 65536)
+@result{} (961933 65536)
(time-since '(13818 19266))
-=> (0 430)
+@result{} (0 430)
(time-less-p '(13818 19266) '(13818 19145))
-=> nil
+@result{} nil
(subtract-time '(13818 19266) '(13818 19145))
-=> (0 121)
+@result{} (0 121)
(days-between "Sat Sep 12 12:21:54 1998 +0200"
"Sat Sep 07 12:21:54 1998 +0200")
-=> 5
+@result{} 5
(date-leap-year-p 2000)
-=> t
+@result{} t
(time-to-day-in-year '(13818 19266))
-=> 255
+@result{} 255
+(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"}.
+
+@item time
+An internal Emacs time. For instance: @code{(13818 26466)}.
+
+@item seconds
+A floating point representation of the internal Emacs time. For
+instance: @code{905595714.0}.
+
+@item days
+An integer number representing the number of days since 00000101. For
+instance: @code{729644}.
+
+@item decoded time
+A list of decoded time. For instance: @code{(54 21 12 12 9 1998 6 t
+7200)}.
+@end table
+
+All the examples above represent the same moment.
+
+These are the functions available:
+
+@table @code
+@item date-to-time
+Take a date and return a time.
+
+@item time-to-seconds
+Take a time and return seconds.
+
+@item seconds-to-time
+Take seconds and return a time.
+
+@item time-to-days
+Take a time and return days.
+
+@item days-to-time
+Take days and return a time.
+
+@item date-to-day
+Take a date and return days.
+
+@item time-to-number-of-days
+Take a time and return the number of days that represents.
+
+@item safe-date-to-time
+Take a date and return a time. If the date is not syntactically valid,
+return a ``zero'' date.
+
+@item time-less-p
+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
+the time between the two times.
+
+@item days-between
+Take two days and return the number of days between those two days.
+
+@item date-leap-year-p
+Take a year number and say whether it's a leap year.
+
+@item time-to-day-in-year
+Take a time and return the day number within the year that the time is
+in.
+
+@end table
@node qp
@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
@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:
+
+@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.
+
+@end table
+
+@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.
+
+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 yenc
+@section yenc
+@cindex yenc
+
+@code{yenc} is used for encoding binaries on Usenet. The following
+function is supplied by this package:
+
+@table @code
+@item yenc-decode-region
+@findex yenc-decode-region
+Decode the encoded text in the region.
+
+@end table
+
+
+@node rfc1843
+@section rfc1843
+@cindex rfc1843
+@cindex HZ
+@cindex Chinese
+
+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 @acronym{ASCII}.
+The next sentence is in GB.~@{<:Ky2;S@{#,NpJ)l6HK!#~@}Bye.
+@end example
+
+Simple enough, and widely used in China.
+
+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
+
+
@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:
@example
-image/*; xv -8 %s
-audio/x-pn-realaudio; rvplayer %s
+image/*; gimp -8 %s
+audio/wav; wavplayer %s
+application/msword; catdoc %s ; copiousoutput ; nametemplate=%s.doc
@end example
-This says that all image files should be displayed with @samp{xv}, and
-that realaudio files should be played by @samp{rvplayer}.
+This says that all image files should be displayed with @code{gimp},
+that WAVE audio files should be played by @code{wavplayer}, and that
+MS-WORD files should be inlined by @code{catdoc}.
The @code{mailcap} library parses this file, and provides functions for
matching types.
@table @code
@item mailcap-parse-mailcaps
@findex mailcap-parse-mailcaps
-Parse the @code{~/.mailcap} 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 Decoding and Viewing
-@chapter Decoding and Viewing
+@node Standards
+@chapter Standards
-This chapter deals with decoding and viewing @sc{mime} messages on a
-higher level.
+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/}.
-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.
+@table @dfn
+@item RFC822
+@itemx STD11
+Standard for the Format of ARPA Internet Text Messages.
-@menu
-* Dissection:: Analyzing a @sc{mime} message.
-* Handles:: Handle manipulations.
-* Display:: Displaying handles.
-@end menu
+@item RFC1036
+Standard for Interchange of USENET Messages
+@item RFC2045
+Format of Internet Message Bodies
-@node Dissection
-@section Dissection
+@item RFC2046
+Media Types
-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.
+@item RFC2047
+Message Header Extensions for Non-@acronym{ASCII} Text
+@item RFC2048
+Registration Procedures
-@node Handles
-@section Handles
+@item RFC2049
+Conformance Criteria and Examples
-A @sc{mime} handle is a list that fully describes a @sc{mime}
-component.
+@item RFC2231
+@acronym{MIME} Parameter Value and Encoded Word Extensions: Character Sets,
+Languages, and Continuations
-The following macros can be used to access elements in a handle:
+@item RFC1843
+HZ - A Data Format for Exchanging Files of Arbitrarily Mixed Chinese and
+@acronym{ASCII} characters
-@table @code
-@item mm-handle-buffer
-@findex mm-handle-buffer
-Return the buffer that holds the contents of the undecoded @sc{mime}
-part.
+@item draft-ietf-drums-msg-fmt-05.txt
+Draft for the successor of RFC822
-@item mm-handle-type
-@findex mm-handle-type
-Return the parsed @code{Content-Type} of the part.
+@item RFC2112
+The @acronym{MIME} Multipart/Related Content-type
-@item mm-handle-encoding
-@findex mm-handle-encoding
-Return the @code{Content-Transfer-Encoding} of the part.
+@item RFC1892
+The Multipart/Report Content Type for the Reporting of Mail System
+Administrative Messages
-@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 mm-handle-set-undisplayer
-@findex mm-handle-set-undisplayer
-Set the undisplayer object.
-
-@item mm-handle-disposition
-@findex mm-handle-disposition
-Return the parsed @code{Content-Disposition} of the part.
+@item RFC2183
+Communicating Presentation Information in Internet Messages: The
+Content-Disposition Header Field
-@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 RFC2646
+Documentation of the text/plain format parameter for flowed text.
@end table
-@node Display
-@section Display
-
-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).
-
-@item mm-inlinable-p
-@findex mm-inlinable-p
-Say whether a @sc{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.
-
-@item mm-destroy-part
-@findex mm-destroy-part
-Free all resources occupied by a part.
-
-@item mm-save-part
-@findex mm-save-part
-Offer to save the part in a file.
-
-@item mm-pipe-part
-@findex mm-pipe-part
-Offer to pipe the part to some process.
-
-@item mm-interactively-view-part
-@findex mm-interactively-view-part
-Prompt for a mailcap method to use to view the part.
-
-@end table
-
-
-
@node Index
@chapter Index
@printindex cp
@contents
@bye
+\f
+@c Local Variables:
+@c mode: texinfo
+@c coding: iso-8859-1
@c End:
projects / gnus / blobdiff