Re: Vote on R6RS, if you have the time to write a 150-word essay

Benedikt Rosenau <rosenau@xxxxxxxxxxxxxx> writes:

Matthias Blume <find@xxxxxxxxxxxxxxxxxxxx> wrote:

In Scheme, LET it is merely syntactic sugar. In today's Scheme you
could even define it yourself if it weren't there already. There is
no "concept" here.

Yes, Scheme's LET can be expressed in terms of Scheme's LAMBDA. But
when one thing can be expressed in terms of another, it does not make
that thing less useful or less desirable.

Scheme emphasized and still emphasizes the introduction of local
variables with an explicit reference to Algol. It shows how important
such a LET is. Programmers use it a lot, because they need it.

I don't know this for sure, but I highly doubt that the mention of
Algol is a reference to the ability of LET-binding a variable.

Adding the ability to define local variables in arbitrary blocks to a
language such as Pascal is nearly trivial. For a programmer, working
around the lack of such variables is also pretty easy -- although
admittedly annoying at times.

The are more disadvantages to not allowing local variables in arbitrary
blocks than you list.

I didn't list any disadvantages, so your statement is trivially true.
But perhaps you could list a few? (I'm not saying there are no
disadvantages. But I don't think they are a big deal compared to
other issues.)

It is telling that you call it a triviality.

What does it tell you?

Why do you think that "triviality" has been added to almost any
programming language, including later versions of Pascal?

Because it is convenient?
.

Loading