Eval - Pro's and Con's (was Re: Dylan rather than CL -- why?)

[Stavros Macrakis <macrakis@osf.org>]

Moon's note was pretty laconic, but the basic problem here is indeed
that you are confusing "read" and "eval".  The expression

	(eval '(+ 1 2))

is the same as

	(eval (read "(+ 1 2)"))

because read is being used to read the program.  You can presume that
there will be some syntax for "quote" in an infix syntax as well.
Suppose this syntax is << ... >>.  Then

	eval(<<1 + 2>>)

would be the same as

	eval(algol-read("1+2")).

If of course you want to mix quoted expression syntax and language
syntax, you will simply have to use the appropriate "read" function.
Thus, you'd have for instance:

	(eval (algol-read "1+2"))
and
	eval(read("(+ 1 2)")).

There is no problem here at all.

As for:

   There aren't many applications for eval, I'll give you that.  There
   are probably even less with an Algol style grammer...

There are legitimate applications for eval, and they have absolutely
nothing to do with the syntax of the language.  Perhaps you are
confusing syntax with the ability to manipulate syntax trees as data
structures?  Most language systems do not give you this capability,
but there's nothing inherent about it.

	-s