Racket

Racket is an evolution of the Scheme Language. A Scheme with Batteries and more. Read R6RS Scheme Specs. It always helps.

Initial Grammar

   program ::= {expr | test | def}*
       def ::= (define <variable name> expr)
      test ::= (check-expect expr expr)
      expr ::= string
           ::= number
           ::= (<function> expr*)
           ::= <variable name>
    string ::= "<character>"
    number ::= positive
           ::= negative
  positive ::= mag
  negative ::= -mag
       mag ::= int
           ::= real
           ::= fraction
       int ::= digit*
     digit ::= 0|1|2|3|4|5|6|7|8|9
      real ::= digit*.digit*
  fraction ::= int/nonzero-int
non-zeroint::= <1|2|3|4|5|6|7|8|9>int

DrRacket

If using DrRacket as an IDE. You can get auto-complete while typing "ctrl-/"

Functions to Explore

(quote 1 2 3)

Testing:

(check-expect val val-expected)
(check-within val val-expected tolerance)

Lists

(list 'a 'b 'c)
(list? x)
(pair? y)
(cons a b)
(a . b)
(car L)
(first L)
(cdr L)
(rest L)
(second L)
(third L) ;; upto tenth
(list-ref L index) ;; (list-ref '(0 1 2 3 4 5 6) 3)
(length L)
(reverse L)
(sort L <)
(sort L >)
(append L1 L2 ...)
> (range 10)
'(0 1 2 3 4 5 6 7 8 9)
> (range 4 10)
'(4 5 6 7 8 9)
> (range 4 10 2)
'(4 6 8)
(make-list 10 'Vikid)
(null? '())
(index-of L member-searched-for)

Links

Eric Clack - Racket Examples

Rash - The Reckless Racket Shell

Fear of Macros

5 Advanced Racket Macros

Fancy App: Scala-Style Magic Lambdas

Beautiful Racket by Matthew Butterick

http://thevikidtruth.com/wiki/?racket

20sep22

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