Re: [PATCH] Per-module reader, take #2

[Neil Jerram]

Kevin Ryde <address@hidden> writes:

> address@hidden (Ludovic Courtès) writes:
>>
>> And what exactly would happen to
>> `primitive-load' (which is the one that triggered the call to
>> `my-zany-reader') when `my-zany-reader' returns?
>
> It sees eof, and stops.  Or it sees the rest of the file if the new
> reader only takes an inlined middle bit of special syntax.  A nested
> parser like that seems pretty clean and pretty normal to me.  I think
> it can do almost everything you're aiming for.

I think Kevin is right that this is possible and would work, but there
is also some merit in the arguments that

- even if it is possible, emulating/duplicating the primitive-load
  loop is a bit dull

- in future the primitive-load loop might acquire more features, and
  it would be nice if those features Just Worked for Ludovic's readers
  also.

On the second point there's a specific feature that I have in mind,
namely being able to set previously specified breakpoints on each
expression as soon as it has been read, and before it is evaluated, so
I'm not just speculating wildly.

So I think the fluid current reader approach is quite nice, as long as
we are happy that it doesn't introduce any significant performance
overhead.

Regards,
        Neil