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> There's a bit of a downside of language extensions vs. integrated languages features.........
The distinction between language extension and language feature is
hard to make in Scheme. Hygienic macros are a feature that the language
is even defined in, but you usually have to install SLIB to get a working version
of them. They're turned off by default in Bigloo, because they are too slow.
Is there really a standard Scheme, Scheme is more like
a family of related standards that are often hard to get to work together.
The record extension is absolutely essential for EOPL and SLIB is the best
to get it in an implementation neutral way and in EOPL2
there's a new abstract data type that seems to be absolutely essential.
If you look at the Guile cookbook code at
PLEAC
you'll see that Guile makes extensive use of the SRFI's
for lists, strings, dates and times, etc.
There is nothing in the syntax that clearly marks the
pattern matching, so mixed in with standard
code it will probably cause confusion and panic....I think.
If I didn't know there was pattern matching lurking in that example
code I .....I.....would have rewritten it with cars and cdrs.
> There are several other pattern matching macro packages around for Scheme
A comparison would be nice.
I'll re-read their papers and post them to Scheme.
But I still think there's a programming ideal lurking in ML and Haskell pattern matching
that Scheme could assimilate:
When you program with these in ML or Haskell it's like *the function has no inside*,
which has to be the *ultimate in refactoring code*, giving the smallest possible
idea embodied in the abstraction of a function. No car'ing and cdr'ing data out
of a cons structure in some gigantic hard to unravel cond (itional).
> But perhaps Real Men should just use all the language extensions they like, and I'm just a wimp :-)
I think the Real Men are the ones who write them. Have you tried reading the implementation code?
Eegads, can I refactor it into something I can understand.
I used to lurk and listen in on all the discussions on comp.lang.scheme
about how Scheme should be abandoned for the strong typing of ML.
My philosophy: before you just dump something, you should see if you
can do what you are moving to (ML) in or with what you already have (Scheme).
And Scheme is the only language that I know of that just continues and continues
and continues, continually branching off extensions, trying to bring all paradigms and new ideas
under its fold, that's probably why Stallman chose it for Guile the GNU scripting/extension
language (and Photoshop-like GIMP )
and that's why I'm glad Scheme is sprouting a new ML head to complement
its many other beautiful faces.
I know Haskell and ML syntax are a lot more suited to types and pattern matching nowadays,
but a couple years from now we'll probably all be programming with customized notations/fonts
(using TeX or some MS Intentional Programming system) or diagrams out of
category theory and reading any sort of textual syntactical representation of a
program will be asking someone to read the machine code generated
by their program or the printout from a core dump.
I also wonder whether there could be a language that was a neutral medium for
other language, that is programs in that language could be translated into equivalent
programs in other languages, perhaps even in other paradigms.....and also translated back
(roundtrip) preserving meaning.
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Algebraic patterns in Scheme