Re: Emacs rewrite in a maintainable language

[Eli Zaretskii]

> From: Óscar Fuentes <address@hidden>
> Date: Sun, 11 Oct 2015 21:43:08 +0200
> 
> Eli Zaretskii <address@hidden> writes:
> 
> > It's all a pipe dream, no more, unless someone steps forward who
> > really intends and is able to do the job. And that is even before we
> > start talking about which alternative language should that be,
> > something that in itself is not a trivial decision.
> 
> I agree, but the key here is that others said "No, there is no need or
> advantage on doing so." Your response is of a very different kind.

Not really.  I just stopped short of rationalizing why something that
is difficult is not really required ;-)

> However, it is not absolutely necessary to have a global understanding
> of the module that it is being translated to the new language. Depending
> on the target language, a shallow knowledge can be sufficient.

Only where the current code is self-contained, i.e. does not make any
serious use of system APIs and is not heavily used by other parts of
Emacs.

If these conditions are false, then a fairly complete understanding is
in fact necessary, otherwise we will have gobs of subtle bugs on our
hands.

Also, depending on the target language, simple 1:1 translation might
make no sense, because it could yield insufficient performance.  In
those cases, the translator will have to reverse-engineer the (largely
undocumented) requirements from the code, and then reimplement them
using more efficient primitives of the target language.  That also
requires a fairly good understanding of what the code does, and why.

And these issues are just the tip of the iceberg.