Variable: coding-system-iso-2022-flags

coding-system-iso-2022-flags is a variable defined in mule.el.gz.

Value

(long-form ascii-at-eol ascii-at-cntl 7-bit locking-shift single-shift
	   designation revision direction init-at-bol designate-at-bol
	   safe latin-extra composition euc-tw-shift use-roman
	   use-oldjis 8-bit-level-4)

Documentation

List of symbols that control ISO-2022 encoder/decoder.

The value of the :flags attribute in the argument of the function define-coding-system must be one of them.

If long-form is specified, use a long designation sequence on encoding for the charsets japanese-jisx0208-1978, chinese-gb2312, and japanese-jisx0208. The long designation sequence doesn't conform to ISO 2022, but is used by such coding systems as compound-text.

If ascii-at-eol is specified, designate ASCII to g0 at end of line on encoding.

If ascii-at-cntl is specified, designate ASCII to g0 before control codes and SPC on encoding.

If 7-bit is specified, use 7-bit code only on encoding.

If locking-shift is specified, decode locking-shift code correctly on decoding, and use locking-shift to invoke a graphic element on encoding.

If single-shift is specified, decode single-shift code correctly on decoding, and use single-shift to invoke a graphic element on encoding. See also 8-bit-level-4 specification.

If designation is specified, decode designation code correctly on decoding, and use designation to designate a charset to a graphic element on encoding.

If revision is specified, produce an escape sequence to specify revision number of a charset on encoding. Such an escape sequence is always correctly decoded on decoding.

If direction is specified, decode ISO6429's code for specifying direction correctly, and produce the code on encoding.

If init-at-bol is specified, on encoding, it is assumed that invocation and designation statuses are reset at each beginning of line even if ascii-at-eol is not specified; thus no codes for resetting them are produced.

If safe is specified, on encoding, characters not supported by a coding are replaced with ?.

If latin-extra is specified, the code-detection routine assumes that a code specified in latin-extra-code-table (which see) is valid.

If composition is specified, an escape sequence to specify composition sequence is correctly decoded on decoding, and is produced on encoding.

If euc-tw-shift is specified, the EUC-TW specific shifting code is correctly decoded on decoding, and is produced on encoding.

If use-roman is specified, JIS0201-1976-Roman is designated instead of ASCII.

If use-oldjis is specified, JIS0208-1976 is designated instead of JIS0208-1983.

If 8-bit-level-4 is specified, the decoder assumes the implementation level "4" for 8-bit codes which means that GL is identified as the single-shift area. The default implementation level for 8-bit code is "4A" which means that GR is identified as the single-shift area.

Source Code

;; Defined in /usr/src/emacs/lisp/international/mule.el.gz
;; Coding system stuff

;; Coding system is a symbol that has been defined by the function
;; `define-coding-system'.

(defconst coding-system-iso-2022-flags
  '(long-form
    ascii-at-eol
    ascii-at-cntl
    7-bit
    locking-shift
    single-shift
    designation
    revision
    direction
    init-at-bol
    designate-at-bol
    safe
    latin-extra
    composition
    euc-tw-shift
    use-roman
    use-oldjis
    8-bit-level-4)
  "List of symbols that control ISO-2022 encoder/decoder.

The value of the `:flags' attribute in the argument of the function
`define-coding-system' must be one of them.

If `long-form' is specified, use a long designation sequence on
encoding for the charsets `japanese-jisx0208-1978', `chinese-gb2312',
and `japanese-jisx0208'.  The long designation sequence doesn't
conform to ISO 2022, but is used by such coding systems as
`compound-text'.

If `ascii-at-eol' is specified, designate ASCII to g0 at end of line
on encoding.

If `ascii-at-cntl' is specified, designate ASCII to g0 before control
codes and SPC on encoding.

If `7-bit' is specified, use 7-bit code only on encoding.

If `locking-shift' is specified, decode locking-shift code correctly
on decoding, and use locking-shift to invoke a graphic element on
encoding.

If `single-shift' is specified, decode single-shift code
correctly on decoding, and use single-shift to invoke a graphic
element on encoding.  See also `8-bit-level-4' specification.

If `designation' is specified, decode designation code correctly on
decoding, and use designation to designate a charset to a graphic
element on encoding.

If `revision' is specified, produce an escape sequence to specify
revision number of a charset on encoding.  Such an escape sequence is
always correctly decoded on decoding.

If `direction' is specified, decode ISO6429's code for specifying
direction correctly, and produce the code on encoding.

If `init-at-bol' is specified, on encoding, it is assumed that
invocation and designation statuses are reset at each beginning of
line even if `ascii-at-eol' is not specified; thus no codes for
resetting them are produced.

If `safe' is specified, on encoding, characters not supported by a
coding are replaced with `?'.

If `latin-extra' is specified, the code-detection routine assumes that a
code specified in `latin-extra-code-table' (which see) is valid.

If `composition' is specified, an escape sequence to specify
composition sequence is correctly decoded on decoding, and is produced
on encoding.

If `euc-tw-shift' is specified, the EUC-TW specific shifting code is
correctly decoded on decoding, and is produced on encoding.

If `use-roman' is specified, JIS0201-1976-Roman is designated instead
of ASCII.

If `use-oldjis' is specified, JIS0208-1976 is designated instead of
JIS0208-1983.

If `8-bit-level-4' is specified, the decoder assumes the
implementation level \"4\" for 8-bit codes which means that GL is
identified as the single-shift area.  The default implementation
level for 8-bit code is \"4A\" which means that GR is identified
as the single-shift area.")