Re: Scripting support (PATCH)

[Marco Gerards <metgerards@student.han.nl>]

Vladimir Serbinenko <phcoder@gmail.com> writes:

> But the next questions are menu entries. I propose the following syntax:
> menu [arguments] name
> {
>     Commands
> }
>
> arguments can be --default, --fallback perhaps some more in the future.
>
> But the main question is about realization. We need to store the
> source code to be able to edit it. Marco and me propose the following
> solution:
> lexer keeps the buffer of current parsed script/block and it stores
> begin and end of tokens in this buffer in yylloc's new fields: buf_beg
> and buf_end. Then when parser founds a menu entry it copies a part of
> buffer using position of command. E.g (schematically):
>
> "menu" string '{' commands '}'

I would even propose something like:

menuargs:	/* Empty */
		menuargs ARG
...
;

menuentry:	"menu" menuargs '{' commands '}' 
;


Or something like that.  Arg is something the scanner can recognize or
so.  I am not sure how that should work :)

> {
>     char was = buf[@4.buf_end];
>     buf[@4.buf_end] = 0;
>     create_menu_command ($2, grub_strdup (&buf[@4.buf_beg]));
> }

I didn't know that bison had such buffer.  I think it is cleaner to
use grub_strndup so you don't have to modify the buffer.  You also
have to pass the result of `commands' ($4 in your example) to
create_menu_command.

> And menu is always stored unparsed and parsed only just before
> execution. Than editing is no problem.

I think you have to parse it immediately and both store parsed and the
unparsed code.  After editing you do the same again.

> Other solution proposed by Marco was to rerun the script file or part
> of it.

This solution is required if you want to be able to edit the complete
script instead of just the separate menu entries.  I think this is not
interesting, but if someone wants to know I can say more about this.

Thanks,
Marco