Re: Interpreter for old basic programs from the line number era

expounded in news:f06a7182-2808-4e4d-8bb0-59f2ababeaf4
@[EMAIL PROTECTED]
> On 12 Mrz., 19:06, "Auric__" <not.my.r...@[EMAIL PROTECTED]
> wrote:
> I will look how curses/terminfo supports color. I fear that there
> might be implementation dependencies or just a fixed color table.
> When a fixed color table exists I have to do some mapping since
> the Seed7 colors are RGB colors with red, green and blue values
> between 0 and 65535.

If you go through curses (rather than through terminfo), you'll need to 
work with "colour pairs". Each pair consists of a background and 
foreground pair of colour selections (1 of 8 predetermined colours). 
Managing pairs is a pain.

For BDB-BASIC, I chose to use a simpler approach. At initialization, you 
can find out from curses how many colour pairs you have to work with (all 
implementations that I have run across so far support a minimum of 64). 
If the implementation should provide less than 64 colour pairs, I 
fallback to monochrome mode.

As long as you have 64 (or more) pairs, you can matrix the pairs for 
every combination of bg/fg colour (assuming 8 colours for 8x8 => 64). 
This allows the basic program to set the FG(x) or BG(x) colour without 
being bothered about "pairs" (or some other terminal context object). The 
interpreter just maps the request to the right colour pair that gives the 
user what he asked for.

Terminfo probably avoids the pair issue (I haven't checked). But I think 
that curses provides so many advantages over using terminfo directly 
(like panels for example), that I wouldn't work at the terminfo level 
except as a last resort. Curses can simplify your work as well, and yet 
be efficient with the traffic sent to the terminal/window. This allows 
you to "redraw" a windowed field completely, but curses will only send 
the parts that have changed for example.

If you're worried about availability of curses on native Windows builds, 
I have successfully used PDCurses (on SF) in MINGW builds. I don't know 
how well it works for BeOS, but I am sure the current maintainer of 
PDCurses would be glad to take patches/input if it needs it (I don't 
recall if it does support BeOS-- perhaps you're already using that).

PDCurses does now support "panels" as well, but does not implement the 
standard "menu" library. I have chosen to write my own "menu" library 
replacement for this reason.

Anyway, just some food for thought on the colour support issue.

Warren.

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