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ACME(4)                    Kernel Interfaces Manual                    ACME(4)

       acme - control files for text windows

       acme [ -f varfont ] [ -F fixfont ] [ file ... ]

       The  text  window system acme(1) serves a variety of files for reading,
       writing, and controlling windows.  Some of them are virtual versions of
       system files for dealing with the virtual console; others control oper-
       ations of acme itself.  When a command is run under acme,  a  directory
       holding  these files is mounted on /mnt/acme (also bound to /mnt/8) and
       also /dev; the files mentioned here appear in both those directories.

       Some of these files supply virtual versions of services available  from
       the  underlying environment, in particular the character terminal files
       cons(3).  (Unlike in 8(1), each command under acme sees the same set of
       files; there is not a distinct /dev/cons for each window.)  Other files
       are unique to acme.

       acme   is a subdirectory used by win (see acme(1)) as a mount point for
              the  acme  files associated with the window in which win is run-
              ning.  It has no specific function under acme itself.

       cons   is the standard and diagnostic output file for all commands  run
              under  acme.   (Input  for commands is redirected to /dev/null.)
              Text written to cons appears in a  window  labeled  dir/+Errors,
              where  dir  is  the directory in which the command was run.  The
              window is created if necessary, but not until text  is  actually

              Is  an  empty  unwritable  file  present only for compatibility;
              there is no way to turn off `echo', for example, under acme.

       index  holds a sequence of lines of text, one per  window.   Each  line
              has  5  decimal  numbers, each formatted in 11 characters plus a
              blank--the window ID; number of characters (runes) in  the  tag;
              number  of characters in the body; a 1 if the window is a direc-
              tory, 0 otherwise; and a 1 if the window is modified,  0  other-
              wise--followed  by  the tag up to a newline if present.  Thus at
              character position 512 starts the name of the window.  If a file
              has  multiple  zeroxed windows open, only the most recently used
              will appear in the index file.

       label  is an empty file, writable without effect, present only for com-
              patibility with 8.

       new    A  directory  analogous  to  the  numbered  directories  (q.v.).
              Accessing any file in new creates a new window.  Thus  to  cause
              text  to appear in a new window, write it to /dev/new/body.  For
              more control, open /dev/new/ctl and use the interface  described

       Each acme window has associated a directory numbered by its ID.  Window
       IDs are chosen sequentially and may be discovered by the ID command, by
       reading  the ctl file, or indirectly through the index file.  The files
       in the numbered directories are as follows.

       addr   may be written with any textual address  (line  number,  regular
              expression,  etc.),  in  the  format  understood by button 3 but
              without the initial colon, including compound addresses, to  set
              the address for text accessed through the data file.  When read,
              it returns the value of the address that would next be  read  or
              written through the data file, in the format #m,#n where m and n
              are character (not byte) offsets.  If m and n are identical, the
              format  is  just #m.  Thus a regular expression may be evaluated
              by writing it to addr and reading it back.  The addr address has
              no effect on the user's selection of text.

       body   holds  contents  of the window body.  It may be read at any byte
              offset.  Text written to body is always appended; the file  off-
              set is ignored.

       ctl    may  be  read  to  recover the five numbers as held in the index
              file, described above.  Text messages may be written to  ctl  to
              affect  the window.  Each message is terminated by a newline and
              multiple messages may be sent in a single write.

                   Set the addr address to that of the user's selected text in
                   the window.

            clean  Mark the window clean as though it has just been written.

                   Remove all text in the tag after the vertical bar.

            del    Equivalent to the Del interactive command.

            delete Equivalent to the Delete interactive command.

                   Set  the  user's  selected  text  in the window to the text
                   addressed by the addr address.

            dump command
                   Set the command string to recreate the window from  a  dump

            dumpdir directory
                   Set  the  directory in which to run the command to recreate
                   the window from a dump file.

            get    Equivalent to the Get interactive  command  with  no  argu-
                   ments; accepts no arguments.

                   When  the ctl file is first opened, regular expression con-
                   text searches in addr addresses  examine  the  whole  file;
                   this  message  restricts subsequent searches to the current
                   addr address.

            mark   Cancel nomark, returning the  window  to  the  usual  state
                   wherein  each modification to the body must be undone indi-

            name name
                   Set the name of the window to name.

            nomark Turn off automatic  `marking'  of  changes,  so  a  set  of
                   related  changes may be undone in a single Undo interactive

                   Turn off automatic `scrolling' of the window to  show  text
                   written to the body.

            put    Equivalent  to  the  Put  interactive command with no argu-
                   ments; accepts no arguments.

            scroll Cancel a noscroll message,  returning  the  window  to  the
                   default  state  wherein  each write to the body file causes
                   the window to `scroll' to display the new text.

            show   Guarantee at least some of the selected text is visible  on
                   the display.

       data   is  used  in conjunction with addr for random access to the con-
              tents of the body.  The file offset is ignored when writing  the
              body  file,  but the character (not byte) offset may be set with
              addr and then read from the data file.  Text, which must contain
              only  whole  characters  (no  `partial  runes'), written to data
              replaces the characters addressed by the addr file and sets  the
              address  to  the  null string at the end of the written text.  A
              read from data returns as many  whole  characters  as  the  read
              count  will permit starting at the beginning of the addr address
              (the end of the address has no effect) and sets the  address  to
              the null string at the end of the returned characters.

       event  When  a window's event file is open, changes to the window occur
              as always but the actions are also reported as messages  to  the
              reader  of  the  file.   Also, user actions with buttons 2 and 3
              (other than chorded Cut and Paste, which behave  normally)  have
              no  immediate effect on the window; it is expected that the pro-
              gram reading the event file will interpret them.   The  messages
              have  a fixed format: a character indicating the origin or cause
              of the action, a character indicating the type  of  the  action,
              four  free-format  blank-terminated  decimal  numbers,  optional
              text, and a newline.  The first and second numbers are the char-
              acter  addresses  of  the  action,  the third is a flag, and the
              final is a count of the characters in the optional  text,  which
              may  itself  contain  newlines.  The origin characters are E for
              writes to the body or tag file, F for actions through  the  win-
              dow's other files, K for the keyboard, and M for the mouse.  The
              type characters are D for text deleted from the body, d for text
              deleted  from  the  tag,  I for text inserted to the body, i for
              text inserted to the tag, L for a button 3 action in the body, l
              for a button 3 action in the tag, X for a button 2 action in the
              body, and x for a button 2 action in the tag.

              If the relevant  text  has  less  than  256  characters,  it  is
              included in the message; otherwise it is elided, the fourth num-
              ber is 0, and the program must read it from  the  data  file  if
              needed.  No text is sent on a D or d message.

              For  D,  d,  I, and i the flag is always zero.  For X and x, the
              flag is a bitwise OR (reported decimally) of the following: 1 if
              the  text indicated is recognized as an acme built-in command; 2
              if the text indicated is a  null  string  that  has  a  non-null
              expansion;  if so, another complete message will follow describ-
              ing the expansion exactly as if it had been indicated explicitly
              (its  flag  will  always  be  0);  8 if the command has an extra
              (chorded) argument; if so, two more complete messages will  fol-
              low  reporting the argument (with all numbers 0 except the char-
              acter count) and where it originated, in the form  of  a  fully-
              qualified button 3 style address.

              For  L  and l, the flag is the bitwise OR of the following: 1 if
              acme can interpret the action without loading a new file; 2 if a
              second  (post-expansion) message follows, analogous to that with
              X messages; 4 if the text is a file or window name (perhaps with
              address) rather than plain literal text.

              For  messages with the 1 bit on in the flag, writing the message
              back to the event file, but with the flag, count, and text omit-
              ted,  will cause the action to be applied to the file exactly as
              it would have been if the event file had not been open.

       tag    holds contents of the window tag.  It may be read  at  any  byte
              offset.  Text written to tag is always appended; the file offset
              is ignored.


       8(1), acme(1), cons(3).