simple CLI architecture

Perhaps the pseudo code below will help, I am not sure I understand what you miss exactly.

You compile your C code, get an executable and run it in a shell.

While(1) { fgets(string, num, stdin); // get a newline from user input parse (string); // Split your string into words // Put them where you want (array)

if (!strcmp ("cmd1", first_word)) cmd1_function(); else if (!strcmp ("cmd2", first_word)) cmd2_function(); ... else if (!strcmp ("Q", first_word)) exit(); }

You might also consider putting the commands in an array, and searching through the array for a matching command. And you might check out the GNU readline library as well for an easy way to support command line editing, history buffer, and with a smidge of programming, tab-completion for your command set. Google is your friend.

Kelly

I would suggest at LEAST backspace/backwards delete support would be useful. However if you are using linux you should have this anyway, from the get string function.

Solution depends on how many commands you are going to support and how many parameters. The simplest solution is spaghetti if .. then .. else statements which is awkward to follow and actual code change to add another function.

Is your command line always

.....

Get a string of the whole input line (knowing what max size is and watching that user cannot input a line beyond that size).

Then ensure you have a table of strings that match the , and a matching table of the function calls. Important note are commands CAse sensitive, if not always upper or lower case the table and what you match it against from the input. The advantage of a table method is you can easily add commands to the table with minimal hassle.

If white space (space, tab) are only used to separate and , consider first scanning the command line to give a list of parameter starting addresses, and a total number of parameters. Changing spaces to NULL character unless you are using external commands.

Scan the table for a string match on the first entry , for a match call the matching function (all functions must use the SAME structure e.g. int func( int ) ). Preferably passing in number of parameters and returning error code for invalid parameters or success. I often write these type of table CLI with a table of structures for embedded work (debug monitor) so that the table is a table of structures like

string address to match mode Unit modes valid command for min arguments max arguments function address

This way some of the repetitive checks are done by one piece of code NOT REPEATED in every other function.

In embedded work I make standard parameter parsing functions to convert string parameters to various number formats with limits check parameters so each function makes the call to convert and check the ranges of inputs and return error codes and values are stored to known variables. Also reducing the duplication of some checks.

e.g. if( conv_hex( &parameter, min, max, mask, &result ) < SUCCESS ) error action else next action

If your parameter string table always contains a pointer to the parameter then external functions (other programmes) can be called as well either because you have reached the end of the table or you have a list of allowed external functions and you have the ability to pass the complete command line across.

The advantages of this approach is that a flexible method of adding extra functions is created, that is easy to maintain, and all your action functions have a common method of calling/return. This way you add a function and you are only testing that function, not changes to add the function as well. This method can be easily adapted for tree level functions where the CLI is working like a menuing system.

Examples of this sort of code do exist on the web.

Hello, Paul! You wrote on Fri, 03 Jun 2005 09:00:56 +0100 (BST):

First of all, I'd like to thank everybody for advices.

PC> Is your command line always

PC> ..... yes. exactly. PC> Get a string of the whole input line (knowing what max size is and PC> watching that user cannot input a line beyond that size).

PC> Then ensure you have a table of strings that match the , and a PC> matching table of the function calls. Important note are commands CAse PC> sensitive, if not always upper or lower case the table and what you PC> match it against from the input. The advantage of a table method is you PC> can easily add commands to the table with minimal hassle. So, you recommend to make two tables (for example in the form of arrays?):

PC> If white space (space, tab) are only used to separate and PC> , consider first scanning the command line to give a list PC> of parameter starting addresses, and a total number of parameters. PC> Changing spaces to NULL character unless you are using external PC> commands. What os the reason of changing spaces into NULL character? [skip]

PC> The advantages of this approach is that a flexible method of adding PC> extra functions is created, that is easy to maintain, and all your PC> action functions have a common method of calling/return. This way you PC> add a function and you are only testing that function, not changes PC> to add the function as well. This method can be easily adapted for PC> tree level functions where the CLI is working like a menuing system.

PC> Examples of this sort of code do exist on the web. I searched but didn't find yet, will try again.

With best regards, Roman Mashak. E-mail: snipped-for-privacy@tusur.ru

Do yourself and all your users a big favor. Use a predefined CLI package. My favorite is embedded TCL.

This way, your CLI is up in a week, has full scripting and control language, and has an off the shelf users manual.

Hello, Scott! You wrote on Fri, 03 Jun 2005 11:52:04 -0700:

??>> command 2) parse command line 3) execute code related to command Seems ??>> to be simple but I don't have any idea right now, that's why I ask for ??>> you to help me out :) With best regards, Roman Mashak. E-mail: ??>> snipped-for-privacy@tusur.ru

SM> Do yourself and all your users a big favor. Use a predefined CLI SM> package. My favorite is embedded TCL. What do you think about using flex+bison for my task? The only reason that stops me is I don't know this well.

With best regards, Roman Mashak. E-mail: snipped-for-privacy@tusur.ru