HELP OUTPUT                                         A. Sloman, Aug 1988

This file gives an overview of documentation on output facilities in
Poplog.

For information on output from 'load marked range', see HELP *LMR.

For more detailed information on basic input and output procedures
for reading information from or writing it to terminals, disks, pipes,
mailboxes, or other devices, see
    REF *SYSIO,  and REF * SYSUTIL.

For basic information on Pop-11 printing facilities see REF * PRINT

For information on character stream input and output, see
    REF * CHARIO

The file names used below are all names of HELP files unless otherwise
specified.

For output to the terminal, see
    *CHAROUT, *CUCHAROUT, *CHARERR, *RAWCHAROUT * POPRAWDEVOUT
    *RAWOUTFLUSH

For output to a device see *DISCOUT, *SYSWRITE

For output from VED see *VEDOUTASCII and *VEDSCREENESCAPE

For output through a pipe to a sub-process (on Unix only) and
information on input from a Unix sub-process see HELP * PIPEUTILS.


-- Printing in Pop-11 programs ----------------------------------------

Several utilities are provided for printing. See REF * PRINT for an
overview of Pop-11 printing facilities.

Many of them send their characters to the character consumer which is
the current value of * CUCHAROUT (a user-assignable variable).

TEACH * SHOWARRAY explains how to print out an array e.g. representing
"grey-levels".

HELP *TRACE explains how to control trace printing for Pop-11
procedures.

HELP * FORMAT_PRINT explains  powerful collection of formatted printing
facilities.

There are help files or ved_?? entries for all of the following
procedures; the help files have the same name as the procedure unless
otherwise specified.

The print arrow =>
    (See HELP *PRINTARROW).

pr(<item>)
    Prints one item.

spr(<item>)
    Prints the item followed by a space

printf(<string>,[%item1% %item2% ... %itemn%])
    or
printf(<itemn>, ...,<item2>,<item1>,<string>)

    Formatted printing of the string, merged with items

prnum(<number>,<pre_decimal_point>,<post_decimal_point>);

    Prints <number> in a format defined by arguments 2 and 3

nl(<number>)
    Prints <number> of newlines

sp(<number>)
    Prints <number> of spaces

tabs(<number>)
    Prints <number> of tabs

The identifiers *NEWLINE, *SPACE and *TAB are variables with the
appropriate characters as values; they can be used with PR to control
formatting of output.

The string concatenator >< can also be used to produce a string of
characters, formatted ready for printing. As it is sensitive to various
user-assignable global variables, a standard version is provided for
directly printing into a string: sys_><

See also
HELP *INPUT - for a list of files on input procedures
REF  *SYSIO - for more detailed information on I/O procedures
REF  *CHARIO- information on character stream I/O

--- C.all/help/output --------------------------------------------------
--- Copyright University of Sussex 1988. All rights reserved. ----------
