hello,
i made a few macros for scheme syntax improvments.
It uses infix Curly expressions syntax described in SRFI 105
and could be combined to use with SRFI 47 in multi dimensional arrays.
Curly expressions allows out of the box syntax more mathematicals like:
{c > t} instead of (> c t)
my macros allows more:
assignations of variables, examples:
(define x '())
{x ← 2}
it returns 2,the value of x
{7 → x} ;; not my own idea suggested by my daughter studying python because
in math we can write 7 = x in an equation but not in python :-)
{cpt <- 0}
{cpt <- {cpt + 1}}
but this would be not complete without a way to have vector and array
access and assignation too:
(define T (make-vector 5))
(vector-set! T 3 7)
{T[3]}
returns 7, the value of T[3]
assignation of vector:
{T[3] <- 7}
works too with multidimensional arrays:
(define a (make-array 999 '(1 2) '(3 4)))
{a[2 4]}
returns 999
harder to code, affectaion between arrays and vectors :
{T[3] <- T[4]}
;; assign and returns the value of T[3]
'{T[3] <- T[4]} will return : (<- ($bracket-apply$ T 3) ($bracket-apply$
T 4))
{a[1 3] <- a[2 4]}
{a[2 4] ← 7}
{1 → a[2 4]}
those works at toplevel of REPL and in statements or block of code or body
of lambda, now works too with LET end LET* and LETREC in the affectation
body and in the statements part:
first a simplified LET named LOCAL as in CLOJURE Lisp that use less
brackets:
(local [ x 1
y (+ x 1)
z (+ 2 y) ]
z
y)
returns 2
new special forms :
(let-arrow* (x ← 1
y ← {x + 1})
y)
returns 2
(let-arrow* [ x 1
y (+ x 1)
z (+ 2 y) ]
z y)
the same works with LETREC:
(letrec-arrow* [ fact ← (lambda (n)
(if {n = 1}
1
{n * (fact {n - 1})}))
]
(fact 5))
;; = 120
this works with Guile Scheme, the implementation of macros needs only R5RS
scheme and the SRFI 105, i hope it could works a day in Racket and others
Scheme implementation .
example in real code:
https://github.com/damien-mattei/scheme4algo/blob/master/SssRec.scm#L245
the code can be found here:
for LET-ARROW* and LETREC-ARROW*:
https://github.com/damien-mattei/library-FunctProg/blob/master/let.scm#L85
Bracket-apply overload and arrows assignations :
https://github.com/damien-mattei/library-FunctProg/blob/master/array.scm#L131
https://github.com/damien-mattei/library-FunctProg/blob/master/array.scm#L101
I wrote a little outdated page blog about that:
http://balistra.canalblog.com/archives/2020/12/01/38692230.html
Racket use different schema for infix notation, one with ($ "string infix
expression") and another with . (dot) such as (x . + . 1) ,they are not
usable ,the latter . dot notation is a real nightmare. The best way would
be to overload the READER of REPL as described in SRFI 105 Curly
expressions.
Damien
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