Re: use variable out side procedure

[Ralf Mattes]

 Sorry if I allow myself to comment as a lurker on this list ....

Am Freitag, 29. Mai 2020 21:26 CEST, Aaron Hill <lilypond@hillvisions.com> 
schrieb:

> On 2020-05-29 6:49 am, Freeman Gilmore wrote:
> > I guess i need a text/course book in scheme that explained little
> > things like that.   That was simple, thank you, ƒg
>
> Might I recommend the following:
>
> ================================
>
> - "The Little Schemer" [1]
>      Daniel P. Friedman, Matthias Felleisen

No, no, no! While all the books you mention are very good books (even so very
special) they are really bad books for smeone trying to learn Scheme to get 
along
with Lilypond.
The first to have a _Strong_ focus on functional programming style only Scheme,
something that often makes life substantially harder when using Guile as a 
scripting
language.

> This work builds on Friedman's original "The Little LISPer" which
> features a very unique way of explaining a programming language.

Yes, they try to form new ways of thinking and reasoning about programming in 
the
abstract, again not what you want to be exposed when trying to get your hands on
Scheme.

[...]
> Plus, the book has illustrations of elephants.

And that pretty much sums up the plus side ....

> After you have finished, there are two follow-ups for consideration:
>
> - "The Seasoned Schemer" [2]
>      Daniel P. Friedman, Matthias Felleisen
> - "The Reasoned Schemer" [3]
>      Daniel P. Friedman, William E. Byrd,
>      Oleg Kiselyov, Jason Hemann

What? The last one is a (brilliant) book about logic programming (wasn't that
the one about kanren "scheme"?). Could you explain why this would be relevant
for Scheme as an extention language to Lilypond. Quite a lot of concept in the
book would be demanding reading for a comp-sci student.
PLEASE - don't be that smugg schemer who scares away beginners mumbling about
the beauty of lamda calculus, the absolute need for hygenic macros (define-macro
vs. syntax-case) or how utterly unuseable languages without 
call-with-current-continuation
are.
While all these things have their beauty and sometimes even their place, one of 
the most
usefull bits of code in my (gosh) almost 30 years of Scheme (and Lisp) 
programming was
the loop macro I imported from Bill Schottstaeds Common Music package - BTW, 
his book
on Common Music is a _much_ better intro to Scheme programming (and it talks 
about
music and alg. composition. But, sadly no pictures of elephants).

Just my 0.02$ rant ....

 Cheers, RalfD

P.S.: Nota bene: all of the following books are Computer Science books.
While they _use_ Scheme none of them is meant as an introduction to the
language. Why isn't  'The Scheme Programming Language (Mit Press) by Kent 
Dybvig'
He's one of the inventors of Scheme. Or, if Racket - why not
'Realm of Racket: Learn to Program, One Game at a Time!' by Felleisen. No 
elephants
either but at least an Intro-Book with "cute" graphics.


> [1]: https://mitpress.mit.edu/books/little-schemer-fourth-edition
> [2]: https://mitpress.mit.edu/books/seasoned-schemer-second-edition
> [3]: https://mitpress.mit.edu/books/reasoned-schemer-second-edition
>
> ================================
>
> - "How to Design Programs" [4]
>      Matthias Felleisen, Robert Bruce Findler,
>      Matthew Flatt, Shriram Krishnamurthi
>
> Compared to "The Little Schemer", this work is presented in a more
> traditional manner.  While the book uses Racket [5] (formerly PLT
> Scheme) for demonstration, the intention is teaching principles of
> program design that are applicable to any language.
>
> Of note, MIT Press has made this work available online for free [6].
>
> [4]: https://mitpress.mit.edu/books/how-design-programs-second-edition
> [5]: https://racket-lang.org/
> [6]: https://htdp.org/
>
>
> -- Aaron Hill
>



--
Ralf Mattes

Hochschule für Musik Freiburg
Projektleitung HISinOne
Schwarzwaldstr. 141, D-79102 Freiburg
http://www.mh-freiburg.de