NAME

colpro − column filter for IBM 4201 Proprinter

SYNOPSIS

colpro [ −bfh ]

DESCRIPTION

Colpro reads the standard input and writes the standard output.  It performs the line overlays implied by reverse line feeds (<Esc>-7 in ASCII) and by forward and reverse half line feeds (<Esc>-9 and <Esc>-8).  Colpro is particularly useful for filtering multiple-column output made with the ‘.rt’ command of nroff and output resulting from use of the tbl(1) preprocessor. Colpro is intended for use with prfl(1). 

Although colpro accepts half line motions in its input, it normally does not emit them on output.  Instead, text appearing between lines is moved to the next lower full line boundary.  This treatment can be suppressed by the −f (fine) option.  In this case the output from colpro may contain forward half line feeds <Esc>-9, but will still never contain either kind of reverse line motion. 

If the −b option is given, colpro assumes the output device in use is not capable of backspacing.  In this case, if several characters are to appear in the same place, only the last one read will be taken. 

Colpro may also be used with the IBM 5152 Graphics Printer.  Note that even though the graphics printer cannot back up, the -b option should not be used since backspaces tell the post filter to use underlining. 

<Esc> sequences are treated according to one of three rules:

 
1) <Esc>-7,8,9 are line positioning commands and are treated as above.
 
2) <Esc>-Ax sequences are assumed to be printer control sequences
(initialize printer, start bold, stop bold, etc.).  These are echoed
to standard output and are treated as if they have “0” width.
 
3) All other <Esc> sequences are assumed to be 3 characters long
(i.e. <Esc> c1 c2), and are echoed to standard output as is (even
if one of the characters is a control character). The filter
assumes the three-character escape sequence specifies a single
printable character.

If the −h option is given, colpro converts white space to tabs to shorten printing time. 

No control characters are passed to the output except space, backspace, tab, return, newline, <Esc> (033) followed by any 2 characters (except 7,8 or 9) and VT (013).  This last character is an alternate form of full reverse line feed, for compatibility with some other hardware conventions.  All other non-printing characters are ignored. 

Colpro is provided primarily for use by proff. 

SEE ALSO

col(1), nroff(1), prfl(1), proff(1), tbl(1), troff(1)

BUGS

Colpro cannot back up more than 128 lines. 

Line length is limited to 800 characters, including backspaces. 

Colpro cannot handle more than 127 unique escape sequences in any 128 contiguous lines of printed text (excluding <Esc>-7,8,9). 

PRPQs 5799-WZQ/5799-PFF: IBM/4.3  —  15 Dec 1986