I find macros much more powerful, thanks.
IMHO The logic of macros and syntax descriptions do only overlap in
part. Assume that the following expression is not a list but a
sequence of characters in a file:
a-b**c**d*e-f*g
Using the usual mathematic precedence rules gives the following
order of evaluation:
((a - ((b ** (c ** d)) * e)) - (f * g))
This order of evaluation is described with the following syntax
rules:
syntax expr: .(). ** .() is <- 4;
syntax expr: .(). * .() is -> 6;
syntax expr: .(). + .() is -> 7;
With just this syntax rules the expressions can be read from the
file. Sure some macros could do this as well, but that is not the
point. Most languages are turing equivalent and therefore they can
do the same things. The point is that some simple syntax rules are
able to turn a sequence of symbols into expressions and
subexpressions.
This should have been
http://seed7.sourceforge.net/manual/objects.htm
instead.
Again, this is not a feature that I am missing in Lisp.
Interesting, you came to a conclusion although the link was not ok.
I thought that OO is present in Lisp. Maybe this is the reason you
don't miss it. Or maybe your answer was just too quick.
DSLs are used routinely in Lisp.
Lisp DSLs probably still use lists. This is not necessary when the
syntax can be changed. Please refrain from saying "You don't need
it" since a customer might have a different idea of what he needs.
By switching to infix, you introduce the distinction, and later you
try to fix it.
Where you get the impression that I try to fix it? Infix is infix
and I don't need to fix it afterwards.
I would rather not create the problem in the first
place.
I see no problem with infix. You probably have other languages in
mind which use a relation between infix operator and corresponding
function. In Seed7 there is no corresponding function and
consequently no problem with infix operators.
You are not being harsh, and you are not being attacked. Criticism
should not be taken as an attack, and I will judge your responses by
their content, not their tone.
Ok.
Again, there is no need to take things personally, please do not try
to claim that I am questioning your intelligence. I was just
questioning the usefulness of Seed7 from my point of view, which is an
entirely legitimate thing to do.
I have no problem when people prefer other languages over Seed7. I
just don't like it when people shout out lound things that are not
really correct. Often wrong assumptions lead to the impression that
Seed7 contains nothing new. Seed7 is designed to imitate constructs
of other languages. It imitates statements of the Pascal/Modula/Ada
world, but the statements could also be totally different. So just
because it can look very conservative does not imply that it is a
form of Pascal. Seed7 is also designed to allow a look behind the
fence. BTW: How do the definitions of special operators like QUOTE,
IF and PROGN look like. Are they defined as macros (since they do
not evaluate all parameters they are probably not functions). In
Seed7 all predefined statements are (at least to some degree)
defined in the language. For a language from the Algol family this
is uncommon. When your goal is to immitate language constructs from
other languages syntax does matter. Seed7 was capable to emulate
the syntax and the semantic of a loop with middle exit which was
suggested by someone planing an Eiffel successor language. Sure
such things could be done with macros, preprocessors or other
technics in any language. In Seed7 this special technics were just
not necessary. The syntax is defined with a syntax statement and
the semantic is defined as function. There are other features which
are done in a different way. Mandatory static type checking and
overloading of functions are done in a way which is different to the
competition. E.g. Overloading resolution is done bottom up which
makes it easier to read and to compile programs. A reaction like
"I don't need it" to such things is just oversimplification.
It is human to just search for a reason to reject something new.
Greetings Thomas Mertes
Seed7 Homepage:
http://seed7.sourceforge.net
Seed7 - The extensible programming language: User defined statements
and operators, abstract data types, templates without special
syntax, OO with interfaces and multiple dispatch, statically typed,
interpreted or compiled, portable, runs under linux/unix/windows.
