Re: poke prompt by default

[Jose E. Marchesi]

> Hi Jose.
>
> On Tue, Nov 21, 2023 at 05:24:48PM +0100, Jose E. Marchesi wrote:
>> 
>> I wonder:
>> 
>> 1. It is easy for the user to write her own pk_prompt function, that may
>>    be as complex as desired.  However, the default version of the
>>    function may use the typical "format string" featuring predefined
>>    tags, such as "(%e:%i)" where %e is replaced by the current
>>    endianness and %i with the selected IO space or "poke" if no IO
>>    space.  This could ease a bit customizing prompts, but it would
>>    require documentation etc.  The question is: would supporting this be
>>    worth the effort and maintenance?
>> 
>
> TL;DR:  We should use Poke. We can provide more prompts in Poke.
>
>
> I disagree with introduing "format string" or other kind of DSL beside the
> Poke.
> Instead we can implement a bunch of different pk_prompt functions with 
> different
> options/styles, which (1) can be a source of inspiration for the users and
> (2) easier to maintain and fix for us.
>
> We can also help the user by providing a dot-command to cycle through these
> different prompts.  Example:

I would like to avoid introducing more dot-commands as much as possible.

IMO what you suggest (hooks and all) is way more complicated than
providing a prompt function that handles a format string:

  var pk_prompt_format = "(%e:%i)";

  fun pk_prompt_default = string:
  {
    /* ... form prompt using pk_prompt_format and retur it ... */
  }

  fun pk_prompt = string:
  {
    return pk_prompt_default;
  }

So we would document:

1. poke will call the pk_prompt function (which has ()string signature)
   in order to get a string with the prompt, every time it needs one.

2. The default definition of pk_prompt uses the format string in
   pk_prompt_format in order to format a prompt string, then returns it.
   Supported tags are %e, %i, etc.

3. You can use your own definition of pk_prompt just by re-defining it.
   Any function is good provided it returns a string.  You can call
   pk_prompt_default (which uses the global format string) from your
   new definition of pk_prompt.

That is all Poke, no need for dot-commands.
The question is: is it worth it?

>
> ```
> (poke) .set prompt
> fixed-string
> endian-filename
> ...
> ```
>
> Then, to select the prompt:
>
> ```
> .set prompt fixed-string
> ```
>
> To change that string:
>
> ```
> .set prompt fixed-string "#!poke!#"
> ```
>
> which will run `pk_prompt_fixed_string = "#!poke!#";' statement.
>
> Easy for user to customize, easier to implement.
>
> I'm not sure about the details of to organize the dot-command, but
> supporting an array of default functions and choosing an index to select
> the default prompt is easy using just Poke (no dot command).
>
> We also provide user with hooks to register functions for prompt.
>
>
>> 2. Is the default prompt the right default?  We are usually very
>>    conservative with defaults (no pretty-printing, plain output mode,
>>    etc) and that may give people the impression that poke is much more
>>    limited that it actually is.  Should we have a default like mine?
>> 
>
>
> Other than pretty-printing (which can be confusing for the new user), yes.
> I think we can improve the user experience by exposing more features.
>
>
> Regards,
> Mohammad-Reza