Notes on the gnuplot help files and documentation.

Gnuplot documentation is available in three ways:

1 - interactively, within gnuplot
2 - as a printed document. 
3 - as a manual page, through the Unix man(1) facility

The first two forms describe the inner workings, and contain
equivalent information, while the third form tells how to run gnuplot.

The two first forms above derive their information from the file
gnuplot.doc, which is the MASTER copy of gnuplot help information. All
other forms, except for gnuplot.1, the man page, are derived from it. 

gnuplot.doc -> gnuplot.hlp 
            -> gnuplot.gih
            -> gnuplot.tex
            -> gnuplot.ms
            -> gnuplot.rtf
    	   	  	 	    		
On VMS the interactive help is supplied by the system help facility,
using the gnuplot.hlp file. This is made with ('make hlp').  On Unix,
AmigaDOS, and MSDOS the interactive help is built in to the program,
and uses the gnuplot.gih file ('make gih').  On MS-Windows, the
Microsoft help compiler converts an 'rtf' file to an 'hlp' file 
which is used by the standard Windows help program.

The printed document is available in either latex or troff/nroff (ms)
format, using gnuplot.tex or gnuplot.ms, derived from gnuplot.doc with
either doc2tex or doc2ms. Type 'make dvi' or 'make nroff'. For troff,
type 'make ms' and then troff -ms gnuplot.ms in whatever way you use
troff.

If VMS users prefer the gnuplot interactive help facility to the
system facility, this can be easily changed in command.c.


Description of the gnuplot.doc format:
--------------------------------------

Here is an example of the DOC master help format:

?
1 gnuplot
 GNUPLOT is a command-driven interactive function plotting program.  It
 ...
?exit
2 exit
 'exit', 'quit' and ...
?expressions
2 expressions
 In general, any mathematical expression accepted by C, ...

 Topics:
 functions operators
?expressions functions
?functions
3 functions
 The functions in GNUPLOT are ...

 Topics:
 abs acos arg ...
?expressions functions abs
?functions abs
?abs
4 abs
 This function returns the absolute value of its argument.  The
 returned value is of the same type as the argument. 
?expressions functions acos
?functions acos
?acos
4 acos
 This function returns the arc cosine (inverse cosine) of its
 argument.  'acos' returns its argument in radians. 


Some notes about the format:
----------------------------
Remember that all text must be able to be processed by gnuplot, VMS,
 nroff, troff, and latex, and always do something reasonable. 
The first column is reserved for control characters.
Text does not start in the first column.
Lines that start in column 2 may be typeset by LaTeX.
Lines that have a space in column 2 are to be printed in a verbatim
 environment by LaTeX.
Tables must have a space in column 2.
Do NOT use tabs in the help file.
Conversion from this format to vax .hlp file involves removal of
 lines starting with [?@#$%] (see doc2hlp). VMS uses the numbers
 to represent a tree. 
Conversion from this format to gnuplot .gih file involves removal of
 lines starting with [0-9@#$%] (see doc2gih). Gnuplot matches your
 help query against the ? lines to find the help information.
 Multiple ? lines for one text block constitute synonyms. The most
 specific should be first, eg 'expressions functions' before 'functions'.
 Spaces are allowed here, but should be single.
Backquote pairs are converted by the doc2tex program into boldface;
 that is, `some text` is converted to {\bf some text}. Be sure to pair
 the backquotes, or the whole document will be boldface!

Control characters in first column:
?    used by .gih format, for builtin interactive help - keyword
0-9  used by VMS help and by doc2{tex,ms} formatters to define level,keyword
@    used by doc2{tex,ms} to define table start/end
#    used by doc2tex: table entry
%    used by doc2ms: table entry
