edw

Sketch of how Scheme might be adapted to enhanced, Clojure-style reader

Multiple procedure arities

;; Clojure
(defn add
  ([] 0)
  ([x] x)
 ([x y] (+ x y))

edw

(define (evil . args)
  (set-cdr! args '())
  args)

(let ((xs '(0 1 2 3)))
  (display (apply evil xs))
  (newline)
  (display xs)
  (newline))

edw

Orange straw poll notes

Edwin Watkeys
2018-11-28

Tallys and Histograms

I wrote a tally in Clojure for my profiling library. I'm interested helping out with this.

Integer sets

edw

;; UNIX-style Brace Expansion
;; (A solution to <http://www.rosettacode.org/wiki/Brace_expansion>.)
;;
;; Edwin Watkeys, Thunk NYC Corp.
;; November 26, 2018
;;
;; (expand-braces "It{{em,alic}iz,erat}e{d,}")
;; => ("Itemized" "Italicized" "Iterated" "Itemize" "Italicize" "Iterate")

(import (scheme list) (srfi 130))

edw

(define (map proc xs)                           
  (let loop ((xs xs) (result '()))              
    (if (null? xs) (reverse result)             
        (loop (cdr xs)                          
              (cons (proc (car xs)) result)))))

edw

(import (chibi parse))

;; JSON Parsing
;; Edwin Watkeys
;; Nov 25, 2018
;;
;; Example usage:
;;
;; (parse datum "{\"foo\": true, \"bar\" : [0,1,2,3.14, .12]}")
;; => (("foo" #t)

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;; This code displays "(0 1)" in Guile, MIT Scheme, and Scheme48. In
;; Chibi, when evaluated from a REPL, it behaves the same, but subsequent
;; evaluations of `(c0)` signal the following error:

;; > (c0)
;; ERROR in child thread: #<Context 140149901512544>
;; ERROR in travel-to-point! on line 657 of file /usr/local/share/chibi/init-7.scm: non procedure application: #f
;; ERROR in travel-to-point! on line 657 of file /usr/local/share/chibi/init-7.scm: non procedure application: #f

(define (counter n)

edw

Scheme (and Lisp) Contra Java (and Nearly Every Other Programming Language)

Edwin Watkeys

History: Originally written September 8, 2005. Updated December 27, 2005; lightly edited December 20, 2013; revised and retitled[0] November 21, 2018; revised November 24, 2018.

One of the big new features of Java 5.0 was a new syntax for iterating over collections. Instead of tediously typing the following:

edw

import Foundation

func printLine(_ x: Double, with stroke: Stroke) {
    let scaledX = log10(x) * 100.0
    print("""
        <line x1="\(scaledX)" x2="\(scaledX)" \(stroke)/>
        """)
}

enum Stroke : CustomStringConvertible {

edw

(define (range n)
  (λ (env)
     (for-each (λ (i) ((displayed i) env))
               (iota n))
     env))

(show #f ">>>" (range 10) "<<<" nl) ; => ">>>0123456789<<<\n"