A critic of Guido's blog on Python's lambda

Alex Martelli aleaxit at yahoo.com
Sun May 7 00:37:43 CEST 2006


Ken Tilton <kentilton at gmail.com> wrote:
   ...
> Looks like dictionaries are no match for the ambiguity of natural 
> language. :) Let me try again: it is Python itself that cannot scale, as
> in gain "new power and capability", and at least in the case of lambda
> it seems to be because of indentation-sensitivity.

In my opinion (and that of several others), the best way for Python to
grow in this regard would be to _lose_ lambda altogether, since named
functions are preferable (and it's an acknowledged Python design
principle that there should ideally be just one obvious way to perform a
task); GvR used to hold the same opinion, but changed his mind recently,
alas, so we'll keep the wart.

But, quite apart from the whole issue of whether it's desirable to
languages to change massively ("add new power and capability" meaning
new enriched features in the language itself), your whole argument is
bogus: it's obvious that _any_ fundamental design choice in an artefact
will influence the feasibility and desirability of future design choices
in future releases of that same, identical artefact.  At a syntax-sugar
level, for example, Lisp's choice to use parentheses as delimiter means
it's undesirable, even unfeasible, to use the single character '(' as an
ordinary identifier in a future release of the language.  Considering
this to mean that Lisp "cannot scale" is just as ridiculous as
considering that Python "cannot scale" by not having an elegant way to
make lambdas heavier and richer -- totally laughable and idiotic.  ``An
unneeded feature "cannot" be added (elegantly) in future releases of the
language'' is just as trivial and acceptable for the unneded feature
``allow ( as an ordinary single-character identifier'' as for the
unneded feature ``allow unnamed functions with all the flexibility of
named ones''.

> By contrast, in On Lisp we see Graham toss off Prolog in Chapter 22 and

Oh, is that the same Graham who writes:

"""
A friend of mine who knows nearly all the widely used languages uses
Python for most of his projects. He says the main reason is that he
likes the way source code looks. That may seem a frivolous reason to
choose one language over another. But it is not so frivolous as it
sounds: when you program, you spend more time reading code than writing
it. You push blobs of source code around the way a sculptor does blobs
of clay. So a language that makes source code ugly is maddening to an
exacting programmer, as clay full of lumps would be to a sculptor.
"""
...?  [[ I suspect that friend is in fact a common friend of mine and
Graham's, the guy you also mention later in your post, and who
introduced Graham and me when G recently came talk at Google (we had
"brushed" before, speaking in the same sessions at conferences and the
like, but had never "met", as in, got introduced and _talked_...;-). ]]

But, no matter, let's get back to Graham's point: significant
indentation is a large part of what gives Python its own special beauty,
uncluttered by unneeded punctuation.  And while you, I, Graham, and that
common friend of ours, might likely agree that Lisp, while entirely
different, has its own eerie beauty, most people's aesthetics are poles
apart from that (why else would major pure-FP languages such as *ML and
Haskell entirely reject Lisp's surface syntax, willingly dropping the
ease of macros, to introduce infix operator syntax etc...? obviously,
their designers' aesthetics weigh parenthesized prefixsyntax negatively,
despite said designers' undeniable depth, skill and excellence).


Alex



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