Unix Programming - Question about write a simple shell : how to output resoult to tty correctly

Author

Question about write a simple shell : how to output resoult to tty correctly

key9

2006-05-16, 7:09 pm

Hi all

I am write a console based application.
Something like a "shell" : enter string and parser explain it, (actually
like cisco's console).

I want my app can be controlled on tty via telnet/ssh. so what I want to
reach is quite like juniper's cli:
sense sample:

host%
host%./app

<APP/MODULE>
>command you input // input command pre defined , it will cause
>"parser" parse it and execute it

Command "command you input" executed!
This execute resoult here.

<APP/MODULE>
> // giving prompt and waiting command again

<APP/MODULE>
>exit
sure to exit (y/n) y

host%

=======================================

My basic design idea:
"
tty? <------ OutputBuffer <------- app
| ^
| |
|-----> VirtualKeyboard -------> parser --------> execute

"

I think what I needed is, maybe like a cli text editor. so I am trying to
read source code of "vi" ,but too much for me -- sorry to say , out of my
mind.

then I am trying to using "ncurses" ,and I found using ncurses's WINDOW* and
set it's y-x manually make more complex mechanism .(scroll screen, echoback
etc.)
also directly using it may cause wrong display on other telnet
client.(tested the "Digipad")

My confuse is between tty and OutBuffer , how to make my OutBuffer class
link with tty more easier ? (may be just like std::cout.)

And what's the next step I should do? any suggest?

Sorry for my knowledge on tty/unix,I am trying.

Thank you very much.

key9

key9

2006-05-16, 7:09 pm

thank you for your reply;

> Are you trying to write a shell in C++?
something like that

> why you should resort to ncurses or anything other than std::cin and
> std::cout to do your command I/O.

>If you are trying to implement some
> kind of command line editing, then you might want to set the tty into
> "raw" mode to allow you to override the built-in editing. If you are
> not trying to implement command line editing, then why not just stick
> with stdio?

May be the story beginning from my self educated roadmap of how
rogramming -- 2 year ,a reversed way:

"OO design ; C++ ; STD; design patterns ; ACE ; UNIX/LINUX BASIC(fd thread
process mutex...);UNIX SOCKET ; UNIX IO, gnu clib...)
(no C experience,start from little/almost no programming experience)

So my application is design/running on my mind for 2 years.

before coding ,I don't think I/O is a problem until I met I must scan "a
keypress" to make my parser to determine action. std::cin have no this
function(getch()),
also I want my app(actually it can be called a Library) can running on
other OS . either GUI and CLI , so there must be a adapter layer.(use
"string" to link them)

I found I have to design an other lib to adapter UNIX I/O,

and may be due to greed, I want lib have "ERR , DEBUG , COUT_..."belong to
itself , they can display on same screen or sparated, or dump to file ,so
it's may be need a window manager.
........
.......
.......

finally I lost my mind , my pool knowledge about ui design drive me crazy.
reinvent the big wheel?

so I found "ncurses" and pin my hope on it , and after serval day's trying ,
almost there , but still have problem --- telnet can not display it
correctly.... crazy again. ^_^

.......

As you see I am a "dabbler" now ,especially no experience on C :-) . may
be afraid , may be just too lazy to study "tty" it self.

now I am reading "Joe's Own Editor" , I hope after another serval days , I
can master it.

ps: I didn't found there's a c++ lib can do such things -----(pure code) a
chartype window manager ,support sub window ,with string to as display ,can
adapter with basic IO . etc...
to wrote it is too expensive for me , if you know one , please tell me.

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