Re: implementing eval command

Moving this to "gdb" list, since it is not a
patch.

On Thu, 2008-02-14 at 18:18 +0200, Yakov Lerner wrote:
> I'd like to make a patch that implements eval command,
as follows.
> I have following idea to implement eval simply:
> Syntax of eval will be similar to the syntax of
'printf' command:
>          eval "string with %..."
comma-separated-expressions
> Implementation relies on existing printf_command()
function,
> by rewriting printf_command into pair of functions, one
that computes
> result of printf as allocated string; both
printf_command and eval_command
> will use compute_printf() function.
> What do you think ?

Hmmm, that would be one way of getting around the 
limitations of some commands that can't accept expressions
as arguments (mentioned in another thread).

What do you see as the context for this eval command?
How do you imagine it will be used?

On Fri, Feb 15, 2008 at 7:58 PM, Michael Snyder
<msnyderspecifix.com> wrote:
> Moving this to "gdb" list, since it is not a
patch.
>
>
>
>  On Thu, 2008-02-14 at 18:18 +0200, Yakov Lerner
wrote:
>  > I'd like to make a patch that implements eval
command, as follows.
>  > I have following idea to implement eval simply:
>  > Syntax of eval will be similar to the syntax of
'printf' command:
>  >          eval "string with %..."
comma-separated-expressions
>  > Implementation relies on existing
printf_command() function,
>  > by rewriting printf_command into pair of
functions, one that computes
>  > result of printf as allocated string; both
printf_command and eval_command
>  > will use compute_printf() function.
>  > What do you think ?
>
>  Hmmm, that would be one way of getting around the
>  limitations of some commands that can't accept
expressions
>  as arguments (mentioned in another thread).
>
>  What do you see as the context for this eval command?
>  How do you imagine it will be used?

Apparently, the capability to insert variable into arbitrary
part of
gdb command is missing in gdb. I hit this several days ago
when I needed
to make a script that uses 'thread apply $num where' to a
subset of threads
in a program that had hundreds of threads and I was told on
the list that this
is impossible.

I also see other requests for eval command on the mailing
list archive.
So, instead of enriching just 'thread apply' command to
accept variable
(or maybe parenthesized expression) I thought it's much more
generic
to have eval command in the end.

I thought about easy way to implement it, and then I got
idea of using
the print-like format and comma-separated arg list.

Yakov