merits of Lisp vs Python

[Juan R.]

Kaz Kylheku ha escrito:

> Kay Schluehr wrote:
> > Juan R. wrote:
> > > A bit ambiguous my reading. What is not feasible in general? Achieving
> > > compositionality?
> >
> > Given two languages L1 = (G1,T1), L2 = (G2, T2 ) where G1, G2 are
> > grammars and T1, T2 transformers that transform source written in L1 or
> > L2 into some base language
> > L0 = (G0, Id ). Can G1 and G2 be combined to create a new grammar G3
> > s.t. the transformers T1 and T2 can be used also to transform  L3 = (G3
> > = G1(x)G2, T3 = T1(+)T2) ? In the general case G3 will be ambigous and
> > the answer is NO. But it could also be YES in many relevant cases. So
> > the question is whether it is necessary and sufficient to check whether
> > the "crossing" between G1 and G2 is feasible i.e. doesn't produce
> > ambiguities.
>
> See, we don't have this problem in Lisp, unless some of the transfomers
> in T1 have names that clash with those in T2. That problem can be
> avoided by placing the macros in separate packages, or by renaming.

Or simply namespacing!

foo from package alpha --> alpha:foo

foo from package beta --> beta:foo

But what composition of different languages? E.g. LISP and Fortran in
the same source.

> In
> In the absence of naming conflicts, the two macro languages L1 and L2
> combine seamlessly into L3, because the transformers T are defined on
> structure, not on lexical grammar. The read grammar doesn't change (and
> is in fact irrelevant, since the whole drama is played out with
> objects, not text). In L1, the grammar is nested lists. In L2, the
> grammar is, again, nested lists. And in L3: nested lists. So that in
> fact, at one level, you don't even recognize them as being different
> languages, but on a different level you can.
>
> The problems you are grappling with are in fact created by the
> invention of an unsuitable encoding. You are in effect solving a puzzle
> that you or others created for you.